Abstract: Matrix metalloproteinases (MMPs) are a family of peptidases trapped within mineralized dentin matrix and involved with degradation of the extracellular matrix components in hybrid layers and caries. Despite their identification through indirect evidences and biochemical assays, MMP-2 and -9 have not been localized within the human dentin extracellular organic matrix. Thus, this study aimed to assess the localization and distribution of MMP-2 and -9 in human dentin organic matrix by employing a correlative field emission in-lens-scanning electron microscopy (FEI-SEM) and transmission electron microscopy (TEM) immunohistochemical approach. Dentin specimens were submitted either to a preembedding or to a postembedding immunolabeling technique using primary monoclonal antibodies anti-MMP-2 and anti-MMP-9 and exposed to a secondary antibody conjugated with gold nanoparticles. MMP-2 and -9 labelings were identified in the demineralized dentin matrix as highly electron-dense gold particles dispersed on the collagen fibrils. Correlative FEI-SEM/TEM observations confirmed that MMP-2 and MMP-9 are endogenous components of the human dentin organic matrix and revealed the three-dimensional relationship between these proteinases and the collagen fibrils, showing that both antibodies yielded a similar labeling pattern. In conclusion, the results of the study contribute to reveal distinct distribution pattern of gelatinases and support the hypothesis that these enzymes are intrinsic constituents of the dentin organic matrix after decalcification.
Abstract: BACKGROUND: Many clinical investigations have demonstrated the benefits of different regenerative approaches in the treatment of infrabony defects. The aim of this investigation was to evaluate the results obtained with the combination of autogenous bone grafting plus calcium sulfate and to compare this outcome with the results obtained using autogenous bone grafting with a bioabsorbable membrane. METHODS: Twelve subjects participated in this split-mouth trial. Twelve 2- or 3-wall periodontal defects were treated with a combination of autogenous bone grafting plus calcium sulfate (test) and were compared to 12 defects treated with autogenous bone grafting with a bioabsorbable membrane (control). Before surgery, subjects were instructed in oral hygiene techniques, and scaling and root planing were completed. Surgery was identical for both groups except for the regenerative material. After healing, subjects followed a periodontal maintenance program. Probing depth (PD), clinical attachment level, and bleeding on probing were recorded at baseline, 6 months, and 6 years. RESULTS: There were no statistical differences between test and control defects at baseline. At 6 months, there was a PD reduction of 4.3 +/- 1.0 mm in the control group and 4.4 +/- 1.1 mm in the test group. There was a clinical attachment gain of 3.5 +/- 1.1 mm in the control group and 3.6 +/- 1.0 mm in the test group. At 6 years, there was a PD reduction of 3.3 +/- 1.0 mm in the control group and 4.2 +/- 1.2 mm in the test group. There was a clinical attachment gain of 2.6 +/- 1.2 mm in the control group and 2.4 +/- 1.1 mm in the test group. Differences between treatment groups were not statistically significant at 6 months or 6 years. CONCLUSION: Both therapies led to significant short- and long-term improvements in the outcome variables assessed.
Abstract: AIM: The aim of the present in vitro study is to compare the resistance to fracture under a cyclic load applied to chamfer-edged vs. shoulder-edged Procera All Ceram cores. MATERIALS AND METHODS: An extracted first maxillary premolar was prepared with a 50 degrees chamfer margin using conventional diamond burs, and an impression was taken using a polyvinylsiloxane. The impression was poured ten times using resin to fabricate dies. The same tooth was retrieved and the 50 degrees chamfer was converted into a 90 degrees shoulder by means of an appropriate diamond bur. An impression was taken and ten more resin dies were fabricated. The resin dies were cast using the lost wax technique in order to obtain brass copies. Impressions of each brass die were taken using a polyvinylsiloxane impression material and poured with die stone. The stone dies were sent to a dental laboratory where densely sintered alumina cores 0.4 mm thick were fabricated using a CAD/CAM process. The alumina cores were then cemented on the brass dies and underwent a fracture test with a cyclic load for 24 hours. Fragments were retrieved for fracture characterization using scanning electron microscopy (SEM). RESULTS: The mean values of fracture resistance for the chamfer samples were 406.10 +/- 67.271 N and 643.90 +/- 32.912 N for the shoulder samples. The Student's t-test revealed a statistically significant difference between groups. CONCLUSIONS: The results of this in vitro study indicate a relationship between the cervical thickness of the alumina cores and their fracture resistance. A shoulder margin could improve the biomechanical performance of posterior single crown alumina restorations.
Abstract: Recent studies have shown that mesenchymal stem cells obtained from periodontal ligament (PDL-MSCs) are multipotent cells that have similar features of the bone marrow and dental pulp MSCs and are capable of proliferating and producing different types of tissue such as bone and tooth associated-tissues. Human PDL-MSCs expanded ex vivo were induced to osteogenesis, seeded in three-dimensional biocompatible scaffolds (fibrin sponge, bovine-derived substitutes) and examined using light, scanning and transmission electron microscopy. Morphological observations showed extensive growth of cellular biomass partially covering the scaffolds after 4 weeks of incubation in mineralization medium. These findings indicate that periodontal ligament can be an easily and efficient autologous source of stem cells with a high expansion capacity and ability to differentiate in osteogenic cells that can colonize and grow connected to bio-compatible scaffold. It can be suggested that the use of PDL-MSCs for generating graft biomaterials is advantageous for bone tissue engineering in regenerative dentistry.
Abstract: BACKGROUND: The purpose of the present study was the clinical and the histologic evaluation of fresh frozen human bone (FFB) allografts used for maxillary sinus-augmentation procedures. METHODS: Ten subjects were treated with maxillary sinus augmentations using FFB. Radiologic measurements were recorded on computed tomography scans preoperatively and 5 months after the sinus surgeries. At 5 months, during implant placement, 10 core biopsies were retrieved and processed for histomorphometric evaluation under light microscopy (LM). Clinical and histomorphometric measurements are presented as mean +/- SD. RESULTS: At baseline, the height of the alveolar ridge measured 4.3 +/- 1.3 mm (mean); after augmentation procedures, at implant positioning, it had a mean height of 16.0 +/- 1.8 mm. All 22 dental implants were clinically healthy after 5 months. LM showed that most of the specimens presented newly formed bone that was completely integrated with preexisting bone. The interface areas between new and old bone were not discernible. Woven bone was present in some areas of the biopsies; however, in the majority of the examined regions, there was mature osseous tissue presenting features of trabecular bone. There was no evidence of an acute inflammatory infiltrate. Histomorphometry revealed that the percentage of bone was 48.15% +/- 14.32%, whereas marrow spaces occupied the rest of the area. CONCLUSION: FFB is a biocompatible material that can be successfully used for maxillary sinus augmentations without interfering with normal reparative bone processes.
Abstract: PURPOSE: To evaluate microtensile bond strength and interfacial nanoleakage expression of adhesive interfaces created by XP-Bond on human deproteinized dentin immediately after bonding and after 6 months of artificial aging. MATERIALS AND METHODS: Noncarious human molars were selected, middle/deep dentin substrates were exposed, and either assigned to group 1 (XP-Bond applied on collagen-depleted dentin) or to group 2 (XP-Bond applied in accordance with manufacturers' instructions). In group 1, the etched dentin surface was treated with 10% NaOCl for 60 s to remove the exposed demineralized organic matrix before XP-Bond application. Composite/dentin beams were obtained in accordance with the microtensile nontrimming technique and either pulled to failure after 24 h or after 6 months' artificial aging. Data were analyzed with two-way ANOVA and Tukey's post-hoc test (p < 0.05). Interfacial nanoleakage evaluation was performed on additional adhesive interfaces to quantify the amount of silver tracer along the interface. RESULTS: The use of NaOCI before XP-Bond application (group 1: 18.9 +/- 5.8 MPa) reduced immediate bond strength by 62% compared to controls (group 2: 49.9 +/- 10.3 MPa; p < 0.5). After 6 months of artificial aging, the bond strength of groups 1 and 2 significantly decreased to 10.1 +/- 2.7 MPa and 35.2 +/- 8.7 MPa, resp (p < 0.05). Interfacial nanoleakage expression along XP-Bond adhesive interfaces was increased either by sodium hypochlorite or by artificial aging. CONCLUSION: The role of collagen fibrils is pivotal for the bonding of XP-Bond to dentin, as decreased immediate bond strength and reduced bond stability over time was found on collagen-depleted dentin.
Abstract: BACKGROUND: In recent years, several reports have suggested, but never definitely demonstrated that dental units (DU) could be potential sources of viral cross-infections sustained by viral agents including HBV, HCV and HIV. This work aims at assessing the risk of HCV cross-infection by dental unit water lines (DUWLs). MATERIALS AND METHODS: Ten anti-HCV positive viremic patients were submitted to dental treatment on three different DU (one unit fully equipped to minimize viral contamination risk). A PCR method using primers for UTR and E2 regions was used to evaluate HCV RNA presence in DUWLs sprays. A modified RNA extraction protocol was developed to eliminate the risk of low sensibility due to the presence of inhibitors in saliva. Sequences obtained from E2 PCR products amplified from blood and oral fluids were analyzed and compared. RESULTS: Fluids collected from three different DU before treatment were always negative for the presence of HCV RNA; after treatment viral contamination was detected in six out of ten cases in conventional DU, in three out of ten cases on the reduced-retraction DU while was never detected in sprays taken from fully equipped DU. Comparison of E2 region sequences obtained from blood and DUWLs sprays showed identity in each patient. CONCLUSION: Here we demonstrate that fixed DUWLs and handpieces can be contaminated by viral agents and become a vehicle of cross-infection and that a specific online active decontamination system developed for both handpieces and fixed waterlines can eliminate this risk.
Abstract: Dentin matrix protein 1 (DMP1) is a non-collagenous matrix protein with a recognized role in the formation of mineralized tissues such as dentin. The aim of this study was to analyze the distribution of DMP1 in human dentin by means of immunofluorescence and high-resolution immunogold labeling. Fully developed, sound human dentin specimens were submitted to fluorescence labeling and post-embedding immunolabeling techniques with a rabbit polyclonal antihuman DMP1 antibody followed by corresponding fluorochrome-conjugated or gold-conjugated secondary antibodies. Both immunofluorescence and immunogold labeling showed an intense labeling associated with the peritubular dentin. In addition, at the ultrastructural level, there was also a moderate and diffuse immunoreaction over intertubular dentin, and a weak labeling within predentin which increased in density towards the mineralization front. This study suggests that in adult human teeth, like in rodents, DMP1 is prevalently concentrated at the level of peritubular dentin and this feature is preserved also in fully developed-teeth. These data are consistent with what has been observed in rodents and suggest that DMP1 plays a role in maintenance of the dentin tubular space.
Abstract: AIM: To assess at the scansion electron microscope (SEM) the structural aspects of enamel hypoplasia (EH) in coeliac disease (CD) with the aim to investigate our hypothesis of a possible significant difference between structural characteristics of EH in CD affected patients and EH of non-coeliac patients. If the presence of specific features of the EH associated with CD were demonstrated, these findings would represent for the dentist early non-invasive clinical markers of diagnosis of CD in case of suspected disease. METHODS: We analysed at SEM two samples of enamel fragments from hypoplasic teeth, both deciduous and permanent, harvested from 10 coeliac children (18 permanent teeth, 6 deciduous teeth; study group) and 10 non-coeliac children (16 permanent teeth, 4 deciduous teeth; control group) treated for dental caries, dental extractions for extensive caries lesions or deciduous teeth exfoliation. RESULTS: Significant structural differences were noted between EH of non-coeliac patients and same dental ? lesion in the group with CD. In the study group, EH defects were predominantly located on the central and lateral incisors, upper and lower, both deciduous and permanent, and on the first permanent molars, and were always simmetrical. EH of permanent teeth of CD affected patients was characterised by prisms more irregularly distributed with irregular margins and less interprismatic substance than observed in non-coeliac EH. The deciduous teeth of the study group showed shorter enamel prisms with a non-parallel direction up to convergence and less interprismatic substance than observed in the control group. CONCLUSION: This morphological analysis at SEM of the hypoplasic enamel defects of a group of coeliac children, the first published in literature, demonstrates that the EH of deciduous and permanent teeth in CD is highly hypomineralised with shorter prisms, more irregularly distributed and less interprismatic substance than observed in the non-coeliac EH. More data are needed to validate the significance OF our observations with the aim to assess if this simple, non-invasive microscopic analysis can be considered effective for the early identification of silent cases of CD that otherwise would not be diagnosed in the paediatric age.
Abstract: Decorin and biglycan, two small leucine-rich proteoglycans, have been proposed to play important roles in matrix-mediated formation of mineralized tissues, and their three-dimensional arrangement in human dentin is still not completely understood. The aim of this study was to immunohistochemically analyze the distribution of decorin and biglycan in human predentin/dentin organic matrix under a high-resolution field emission in-lens scanning electron microscope (FEI-SEM) and a transmission electron microscope (TEM). Tooth dentin specimens were submitted to either a preembedding or a postembedding immunolabeling technique using primary antibodies antidecorin and antibiglycan and gold-conjugated secondary antibodies. Correlative FEI-SEM/TEM observations showed that the two antibodies yielded a similar labeling pattern over the processes of odontoblasts and the predentin. Decorin and biglycan were mainly associated with the collagen fibers within the predentin layer, revealing a moderate immunoreaction that was significantly higher compared to the one observed on dentin. Thus, a generally weak labeling for decorin was found in dentin, which, however, was significantly higher on odontoblast processes within dentinal tubules than in intertubular dentin. On the other hand, biglycan immunolocalization on dentin revealed few gold particles rather uniformly distributed, without showing significant differences between tubular and intertubular regions. In conclusion, this study reveals distinct distribution patterns of decorin and biglycan and their relation with collagen. Decorin's and biglycan's precise roles within prematrix and mineralized matrix in human teeth should be further clarified.
Abstract: BACKGROUND: Placement of dental implants in the posterior maxilla has been associated with higher rates of failure that are due, in part, to the poor bone quality of this region. The purpose of the present study was the histologic and histomorphometric evaluation of the bone around a new implant surface treatment created by a deposition of nanometer-sized calcium phosphate particles added to the dual acid-etched surface. METHODS: One custom-made 2 x 10-mm site evaluation implant (SEI) with this novel treatment surface (test) and one SEI with the dual acid-etched surface without treatment (control) were placed in the posterior maxilla of 15 patients. All SEIs were retrieved after 2 months and evaluated under confocal laser scanning microscopy (CLSM) and by light microscopy for histomorphometric analysis of the bone-implant contact (BIC). RESULTS: Histologic observations in control SEIs showed formation of new bone around the implant surface; however, it was not always in direct contact with the entire perimeter of the threads. The mean BIC was 19% +/- 14.2%. Test SEIs showed peri-implant bone tightly contacting the implant surface and better adapted to the threads. Three-dimensional reconstruction of sections obtained using CLSM showed the intimacy of the contact between bone and test SEI surface through the entire thickness of the specimens. The mean BIC was 32.2% +/- 18.5%. CONCLUSIONS: After 2 months of healing, comparison of the BIC values showed a statistically significant greater mean BIC for test SEIs than for controls. The clinical implications of these results included shortening of the implant healing period and earlier loading protocols.
Abstract: OBJECTIVE: To record and compare the surface electromyographic (sEMG) activity of masticatory, neck, and trunk muscles at different functional requirements of the stomatognathic system in an adult sample classified according to the mandibular divergence angle (SN-GoGn angle). MATERIALS AND METHODS: 60 Caucasian adult subjects were classified on the basis of SN-GoGn angle: 20 subjects with normal mandibular divergence, 20 subjects with lower angles, and 20 subjects with higher angles. Their sEMG activity was recorded at mandibular rest position and during maximal voluntary clenching. RESULTS: sEMG activity of subjects with a lower angle was significantly higher than that of subjects in the other two groups at mandibular rest position for the masseter, the anterior temporal, the upper trapezius, and the posterior cervical muscles. During maximal voluntary clenching, no significant difference was observed in the sEMG activity of the masticatory muscles among the three groups. However, the sEMG activity of the posterior cervicals and that of the upper trapezius were significantly higher in subjects with a lower angle than in the other two groups. CONCLUSION: Skeletal class does seem to affect the sEMG pattern activity of the masticatory, neck, and trunk muscles.
Abstract: BACKGROUND: Calcium sulfate is a simple, biocompatible material with a very long, safe clinical history in several different fields of medicine. It is a rapidly resorbing material that leaves behind calcium phosphate lattice, which promotes bone regeneration. OBJECTIVE: The aim of this study was a histological and ultrastructural evaluation of the tissues in a peri-implant site regenerated with calcium sulfate. MATERIALS AND METHODS: The specimens were processed for observation under light and transmission electron microscopes. RESULTS: In light microscopy, trabecular bone was present. No remnants of calcium sulfate were present. Transmission electron microscopy showed, in the areas of the interface with the implant surface, features of mature bone with many osteocytes. An amorphous layer and/or osteoid seam separated this mature bone from the metal surface. CONCLUSION: The results confirm the high biocompatibility and rapid resorption of calcium sulfate.
Abstract: AIM: To identify type I- (I-CF) and type III-collagen fibrils (III-CF) and chondroitin 4/6 sulphate (CS) within human pre-dentine by means of a correlative analysis under field emission in-lens-scanning electron microscopy (FEI-SEM) and transmission electron microscopy (TEM). METHODOLOGY: Human-extracted teeth were obtained and submitted to either a pre-embedding or a post-embedding immunolabelling procedure using monoclonal primary antibodies anti-I-CF, anti-III-CF and anti-CS. Gold-conjugated secondary antibodies were coupled to primary antibodies to visualize labelling under the electron beam. Correlative labelling patterns were obtained for I-CF and CS under both FEI-SEM and TEM. RESULTS: Field emission in lens-SEM analysis revealed an intricate three-dimensional network of I-CF and CS clarifying the intimate relationship between the two main components of the pre-dentine organic matrix. TEM analysis revealed odontoblasts exhibiting intracellular labelling for CS, which became more intense and diffuse over the pre-dentine organic matrix. The same diffuse immunoreaction was revealed for I-CF, whereas a weak immunolocalization of III-CF was found scattered throughout the pre-dentine layer and over the collagen fibrils. CONCLUSIONS: Both the pre- and post-embedding immunohistochemical approaches have led to the visualization of CF- and CS-labelling distribution within the pre-dentine layer, adding further knowledge on the elucidation of collagen-proteoglycans interaction in the organic matrix of human dental roots.
Abstract: Mesenchymal stem cells from periodontal ligament (PDL-MSCs) hold great promise for bone regeneration. Most studies regarding the osteogenic differentiation of stem cells from periodontal tissue suggest that PDL cells may have many osteoblast-like properties, including the ability to form calcified nodules in vitro. This study investigated the morphological and histochemistry aspects of human PDL-MSCs, induced for osteogenic differentiation and seeded on a xenogenic porcine bone substitute in vitro, at different times of incubation. This biomaterial seems physically identical to human bone, and it has been reported to be osteoconductive. Our results indicated that the cells had a high affinity for the three-dimensional biomaterials; in fact, cellular proliferation and colonization was evident, and after 21 days the adherent cells started to detach themselves from the substrate, and at 30 days of incubation in differentiation medium, the cells completely lost the adhesion to the Petri's disk, englobing all bioparticles. In conclusion, the in vitro behaviour of PDL-MSCs and their relationship with three-dimensional scaffold biomaterials encourage in vivo investigations for their use in dental tissue regeneration.
Abstract: Discomfort associated with wearing an intraoral splint represents a problem in the management of temporomandibular joint (TMJ) internal derangement. This study evaluated whether the use of a mandibular splint during the day and a maxillary splint at night could be more comfortable and therefore as efficacious in internal derangement treatment as a maxillary splint (AR splint). Fifty (50) patients (average age 28.8; range 14-63) with confirmed internal derangement in at least one TMJ were divided into three groups: 20 patients treated with AR splint (Group I); 20 patients treated with a SVED (Sagittal Vertical Extrusion Device) and a MORA (Mandibular Anterior Repositioning Splint) (Group II); and 10 patients who underwent no treatment (Control Group). Joint noise, pain intensity and its character (as constant or chewing/biting pain), muscular pain, and subjective relief were evaluated monthly before treatment began (T0) and for six months thereafter. The following results were found: 1. Subjects in Group I and Group II displayed a significant decrease in joint pain (p<0.001), constant pain (p<0.001), chewing/biting pain (p<0.001), joint noise and muscle pain from the beginning through the sixth month follow-ups; 2. At T1 and T2, subjects in Group II reported significantly lower discomfort associated with the devices than subjects in Group I. The use of two splints seems to be as efficacious as the use of an AR maxillary splint; however an AR splint is considered more comfortable by patients, especially during the first months of therapy.
Abstract: Current literature reports that surface acid etching can improve bone--implant contact (BIC). The aim of this study was to evaluate the differences of BIC between acid-etched (Osseotite) and machined surface implants. Six white New Zealand mature rabbits were used in the present investigation. Each rabbit received two implants, specially made with two surfaces on it (one acid-etched and one machined) into each tibia. A total of 24 implants were inserted. Two animals each were killed at 15, 30, and 60 days after implant placement. Histomorphometry of BIC was statistically evaluated. The acid-etched surfaces showed a greater bone contact percentage than the machined ones during the early phase of healing (15 days), which was not statistically significant. On the other hand, after 30 and 60 days, the differences of BIC between acid-etched and machined surfaces were statistically significant. The acid-etched surface appears to improve BIC at a later stage of healing.
Abstract: Porous hydroxyapatite (HA) is a calcium-phosphate-based material that is biocompatible, nonimmunological, and osteoconductive, and has a macroporosity of about 200 to 800 microm. The pores seem to be able to induce migration, adhesion, and proliferation of osteoblasts inside the pore network and to promote angiogenesis inside the pore system. The aim of this study was to evaluate the clinical behavior and the histological and ultrastructural aspects of porous HA in maxillary sinus augmentation procedures. Twenty-four patients (19 men, 5 women; average age 53.4 years) in good general physical and mental health and with partially or completely edentulous maxillae were selected for this study. Six months after sinus floor elevation, at the time of dental implant placement, biopsies were carried out under local anesthesia. These bone cores were cut in half and were processed for light and transmission electron microscopy. After a mean 3 years after implantation, all implants are clinically in function and no surgical or prosthetic complications have occurred. Under light microscopy, newly formed bone was 38.5% +/- 4.5%, whereas the residual biomaterial represented 12% +/- 2.3% and the marrow spaces represented 44.6% +/- 4.2%. In addition, in the majority of cases, the biomaterial particles were in close contact with the bone, which appeared compact with the characteristic features of well-organized lamellar bone. A cement-like line was slightly visible at the bone-biomaterial interface, but there were no gaps or interposed connective tissue in between. A high quantity (about 40%) of newly formed bone was present. Bone was closely apposed to the biomaterials particles as shown in light microscopy and transmission electron microscopy. Moreover, no signs of inflammatory cell infiltrate or foreign body reaction were present. Also, most of the biomaterial was resorbed and only a small quantity (a little more than 10%) was still present. The results of our study show that porous HA can be a suitable synthetic material for bone regeneration in maxillary sinus augmentation procedures.
Abstract: OBJECTIVE: Rehabilitation of the edentulous posterior maxilla with dental implants can be difficult because of insufficient bone volume caused by pneumatization of the maxillary sinus and crestal bone resorption. Different biomaterials have been used for sinus augmentation. The aim of the study was to compare different materials in maxillary sinus augmentation in man. METHODS: A total of 94 patients participated in this study. Inclusion criteria were maxillary partial (unilateral or bilateral) edentulism involving the premolar/molar areas, and the presence of 3-5-mm crestal bone between the sinus floor and alveolar ridge. A total of 362 implants were inserted. There were 9 biomaterials used in the sinus augmentation procedures. Each patient underwent 1 biopsy after 6 months. A total of 144 specimens were retrieved. RESULTS: None of the 94 patients had complications. All implants were stable, and x-ray examination showed dense bone around the implants. Mean follow-up was 4 years. There were 7 implants that failed. Histologic resultsshowed that almost all the particles of the different biomaterials (i.e., autologous bone, demineralized freeze-dried bone allograft Biocoral [Inoteb, St. Gonnery, France], Bioglass [US Biomaterials, Alachua, FL], Fisiograft [Ghimas, Bologna, Italy], PepGen P-15 [Dentsply Friadent CeraMed, Lakewood, CO], calcium sulfate, Bio-Oss [Geistlich Pharma AG, Wohlhusen, Switzerland], and hydroxyapatite) were surrounded by bone. Some biomaterials were more resorbable than others. Included are the histomorphometry clarified features of the newly formed bone around the different grafted particles. CONCLUSION: All biomaterials examined resulted in being biocompatible and seemed to improve new bone formation in maxillary sinus lift. No signs of inflammation were present. The data are very encouraging because of the high number of successfully treated patients and the good quality of bone found in the retrieved specimens.
Abstract: Many adult tissues contain a population of stem cells that have the ability to regenerate after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues. The studies on stem cells are thought to be very important and, in fact, it has been shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone and tooth-associated tissues, but also other types of tissues. Several studies have focused on the identification of odontogenic progenitors from oral tissues, and it has been shown that the mesenchymal stem cells obtained from periodontal ligament and dental pulp could have similar morphological and phenotypical features of the bone marrow mesenchymal cells. In fact a population of homogeneous human mesenchymal stem cells derived from periodontal ligament and dental pulp, and proliferating in culture with a well-spread morphology, can be recovered and characterized. Since these cells are considered as candidates for regenerative medicine, the knowledge of the cell differentiation mechanisms is imperative for the development of predictable techniques in implant dentistry, oral surgery and maxillo-facial reconstruction. Thus, future research efforts might be focused on the potential use of this cell population in tissue engineering. Further studies will be carried out to elucidate the molecular mechanisms involved in their maintenance and differentiation in vitro and in vivo.
Abstract: BACKGROUND: The purpose of the present study was the histologic and ultrastructural evaluation of a biomaterial composed of cortical pig bone in the form of granules. METHODS: After maxillary sinus augmentation using this biomaterial, 10 specimens were retrieved after 5 months in 10 patients using this biomaterial. The specimens were processed to be observed under light microscopy (LM) and transmission electron microscopy (TEM). Histomorphometric measurements were presented by means +/- standard deviations. RESULTS: LM showed that most of the particles were surrounded by newly formed bone. In some areas, the osteoid matrix was present; however, mainly compact bone was present at the interface. There was no evidence of an acute inflammatory infiltrate. The newly formed bone was 36% +/- 2.8% and marrow spaces were 38% +/- 1.6%, whereas residual grafted material was 31% +/- 1.6%. Under TEM, all phases of bone formation (osteoid matrix, woven, and lamellar bone) were observed in proximity with the biomaterial particles. The bone-biomaterial interface showed a close contact between the porcine bone particles and the surrounding bone that had mainly features of mature bone with numerous osteocytes. A lamina limitans was sometimes present at this interface. CONCLUSIONS: According to our knowledge, this is the first study presenting data on TEM of a porcine bone-derived biomaterial used in sinus augmentation procedures in humans. Our findings show that this is a biocompatible biomaterial that can be used for maxillary sinus augmentation procedures without interfering with the normal reparative bone processes.
Abstract: STATEMENT OF PROBLEM: Ovate pontics mimic the natural tooth contour and provide an esthetic result however, few studies have evaluated the histological changes in underlying tissues. PURPOSE: The purpose of this pilot study was to histologically evaluate the healing of gingival tissues in contact with provisional ovate pontics after 2 weeks. MATERIAL AND METHODS: Three patients requiring fixed partial dentures participated in this study. The provisional restorations consisted of a fixed partial denture having 2 ovate pontics: one in acrylic resin (Jet), with an ovate shell made of low-fusing ceramic (Duceram LFC); the other made completely of the same acrylic resin (control). After 2 weeks, biopsies of the gingival tissues beneath the pontics were retrieved for histological examination, and immunohistochemistry for evaluation of the vascular endothelial growth factor (VEGF) was performed. Data were analyzed using descriptive statistics. RESULTS: Clinically, all of the ovate pontic-prepared sites showed partial healing. Histologically, the thickness of the entire mucosa was similar in both specimens; however, in some regions, the epithelium presented ulcerations that were generally deeper and more frequent in control sites than in test sites. Immunohistochemical results showed that tissues beneath LFC pontics seemed to be less inflamed since they demonstrated a lower expression of VEGF (10.7 +/- .8) compared to those beneath acrylic resin ovate pontics (33.9 +/- 2.5). CONCLUSION: This pilot study demonstrated that the placement of provisional LFC ovate pontics may be advantageous for the reparative processes of the underlying tissues.
Abstract: Biological interactions occurring at the bone-biomaterial interface are critical for long-term clinical success. Bio-Oss is a deproteinized, sterilized bovine bone that has been extensively used in bone regeneration procedures. The aim of the present study was a comparative light, scanning, and electron microscopy evaluation of the interface between Bio-Oss and bone in specimens retrieved after sinus augmentation procedures. Under light microscopy, most of the particles were surrounded by newly formed bone, while in a few cases, at the interface of some particles it was possible to observe marrow spaces and biological fluids. Under scanning electron microscopy, in most cases, the particle perimeter appeared lined by bone that was tightly adherent to the biomaterial surface. Transmission electron microscopy showed that the bone tissue around the biomaterial showed all the phases of the bone healing process. In some areas, randomly organized collagen fibers were present, while in other areas, newly formed compact bone was present. In the first bone lamella collagen fibers contacting the Bio-Oss surface were oriented at 243.73 +/- 7.12 degrees (mean +/- SD), while in the rest of the lamella they were oriented at 288.05 +/- 4.86 degrees (mean +/- SD) with a statistically significant difference of 44.32 degrees (p < 0.001). In the same areas the intensity of gray value was 172.56 +/- 18.15 (mean +/- SD) near the biomaterial surface and 158.71 +/- 21.95 (mean +/- SD) in the other part of the lamella with an unstatistically significant difference of 13.79 (p = 0.071). At the bone-biomaterial interface there was also an electron-dense layer similar to cement lines. This layer had a variable morphology being, in some areas, a thin line, and in other areas, a thick irregular band. The analyses showed that Bio-Oss particles do not interfere with the normal osseous healing process after sinus lift procedures and promote new bone formation. In conclusion, this study serves as a better understanding of the morphologic characteristics of Bio-Oss and its interaction with the surrounding tissues.
Abstract: PepGen P-15 is a combination natural anorganic bovine-derived hydroxyapatite matrix coupled with a synthetic cell-binding peptide (P-15). This material has improved bone formation in periodontal osseous defects and bone regenerative procedures. There were 3 specimens retrieved 18 months after a sinus lifting procedure using PepGen P-15. These specimens were treated to be observed under light microscopy and transmission electron microscopy. Light microscopy showed that most of the particles were surrounded by newly formed bone. In some areas, osteoid matrix was present. No acute inflammatory infiltrate was present. In transmission electron microscopy, all phases of bone formation (i.e., osteoid matrix, woven bone, and lamellar bone) were observed in the newly formed bone around the biomaterial particles. In some regions, this newly formed bone seemed to present interdigitations connecting to or entering into the particle surface. To our knowledge, this is the first report presenting data on transmission electron microscopy of PepGen P-15 used in a sinus augmentation procedure in man. Our results confirm previous reports on the clinical effectiveness of this material.
Abstract: Bone substitutes have been used for the treatment of bone defects. The objective of this study was to ultrastructurally evaluate the healing pattern of bone defects filled with a copolymer of polylactic/polyglycolic acid (FisiograftR) at a time point in which it is expected to be only partially degraded, with the purpose to ultrastructurally analyze how the bone is forming around the grafting material. Three 5-mm-diameter bone defects were created in each tibia from 5 rabbits (average weight 2.5 kg) in which the material was randomly implanted. Animals were sacrificed 30 days after surgery and the 30 bone defects were fixed in 2% glutaraldehyde-2.5% formaldehyde, under microwave irradiation, decalcified in EDTA, embedded in Spurr resin, and examined in a Jeol 1010 TEM. All the bone defects were filled with connective tissue, interspersed with different amounts of the filling material and newly formed bone trabeculae. In areas where the degrading copolymer was present in small amounts, newly formed bone matrix was detected; it was deposited by osteoblast-like cells in close relation to the copolymer. In areas where the degrading copolymer formed accumulates, an amorphous multilayered material was identified between the connective tissue and the copolymer. In summary, the copolymer of PLA/PGA studied appears to be an osteoconductive material when it is used to fill bone defects.
Abstract: BACKGROUND: The aim of this study was to evaluate the predictability of the free connective tissue graft in prosthetically treated patients needing gingival augmentation. The following outcome variables were studied 1) dimensional changes of free connective gingival grafts; 2) color blending with adjacent tissues; and 3) periodontal and marginal health status, when compared to a non-surgical control group. METHODS: Two groups of patients without periodontitis were investigated. The test group (group A) consisted of 16 patients. The inclusion criteria for surgical correction were: 1) at least 1 site lacking (<1 mm) keratinized tissue and/or lacking vestibular depth; 2) insufficient plaque control; and 3) the selected site was scheduled to undergo or had already received a fixed prosthetic restoration. The control group (group B) included 14 patients with the same inclusion criteria, but declining to undergo surgery. Group A patients were treated with a free connective tissue graft to augment the keratinized tissue at the selected sites. The size of the graft was recorded at baseline (surgical intervention) and the width of keratinized tissue was measured at 1, 4, 26, and 52 weeks. Gingival inflammation and plaque accumulation were assessed at baseline and 52 weeks in both groups. Probing depth and clinical attachment levels were recorded at baseline and 26 and 52 weeks in both groups. Evaluation of the esthetic results was carried out at the end of the study. All patients in both groups received oral hygiene instructions and supragingival plaque and calculus removal before and at the end of the investigation. RESULTS: In group A, the results showed a mean amount of keratinized tissue of 5.81 +/- 1.42 mm at 26 weeks and 5.25 +/- 1.34 mm at 52 weeks. Mean shrinkage of the graft was 10.2% (P = 0.001) at 1 week, 28.4% (P = 0.0004) at 4 weeks, 37.2% (P = 0.0004) at 26 weeks, and 43.25% (P = 0.0004) at 52 weeks. All the dimensional changes were statistically significant, when compared to baseline. Evaluation of color blending with the surrounding gingiva demonstrated an "excellent result" at 52 weeks with an 87.5% agreement among the three masked examiners. In the test group, the periodontal indices improved or remained stable; in the control group, there was a minor improvement of the indices, with three patients showing a worse gingival inflammation score and two a worse plaque score. CONCLUSION: Although these results are not conclusive, mostly due to a lack of a large enough sample population, the statistically significant results shown in this investigation tend to support the use of gingival augmentation procedures in prosthetic patients with insufficient keratinized gingiva and/or shallow or absent vestibules, when they cannot demonstrate adequate plaque control.
Abstract: Calcium sulfate (CaS) has been shown to be a reasonable alternative to autogenous bone graft for treating bone lesions in dentistry. The aim of this work was an histological study of the bone healing of defects treated with calcium sulfate in the form of cement or beads, in animal. Eight New Zealand rabbits, weighing about 2.5 Kg were used in this study. In each rabbit, four 6 mm bone defects were created in the tibial metaphysis. The 2 defects in the right tibia were filled with calcium sulfate as cement, while the 2 defects in the left one were filled with calcium sulfate as beads. Four rabbits were killed after respectively 2 and 4 weeks, with an intravenous injection of Tanax, and the block sections, containing the bone defects, were retrieved. A total of 16 defects filled by cement and a total of 16 defects filled by beads were retrieved. The specimens were processed to obtain thin ground sections with the Precise 1 Automated System. In the first phases of healing it was possible to observe an intense osteoblastic activity, and in some areas osteoid matrix was present. After two weeks the calcium sulfate (both cement and beads) was still present, and biological fluids and cells were present inside the material. Newly formed bone surrounded the calcium sulfate and filled about 10% of the defect. After four weeks the calcium sulfate was almost completely resorbed and substituted by new bone. Approximately 34% of the defects were filled by newly formed bone. BEI and XRM evaluations showed the structural components of the filled defects. In none of the specimens were inflammatory cells present. No significant differences were found using both calcium sulfate as cement and beads, and they both have shown a high biocompatibility, appearing to promote newly bone formation in the rabbit model, and they did not induce any untoward effect on the bone regeneration processes.
Abstract: BACKGROUND: Following tooth extraction, remodeling and resorption of the alveolar bone at the extraction site characterize wound healing. This produces a reduction in ridge volume and difficulties in delayed placement of implants in an ideal position. Medical grade calcium sulfate hemihydrate (MGCSH) has been proposed as a graft material in extraction sockets to minimize the reduction in ridge volume. The aim of the present study was to investigate the influence of MGCSH on the histopathologic pattern of intrasocket regenerated bone and to evaluate histologically the healed MGCSH grafted extraction socket site 3 months postextraction METHODS: MGCSH was grafted in 10 fresh human extraction sockets in 10 patients. Five post-extraction sockets were used as controls. At 3 months a cylindrical tissue specimen, 2.5 mm in diameter, was trephined from the previously grafted site followed by implant placement. Non-decalcified specimens were sectioned at a cross-horizontal plane and stained with fast green, toluidine blue, and Van Kossa stains for histological and histomorphometrical examination. RESULTS: Histologically, MGCSH was not observed in most of the specimens. Newly formed bone with lamellar arrangements was identified in all the horizontal sections with no difference between apical, medium, and coronal areas. The mean trabecular area in the coronal sections was 58.6% +/- 9.2%; in the medium sections, 58.1% +/- 6.2%; and in the apical sections, 58.3% +/- 7.8%. The differences were not statistically significant. CONCLUSION: MGCSH seems to be an ideal graft material in extraction socket bone regeneration because it is almost completely resorbable, and it allows a new trabecular bone arrangement at 3 months.
Abstract: Inflammatory odontogenic cysts include radicular cysts and its etiological variance, residual cysts. Among these lesions, the radicular cyst is the most frequent. It is caused by the growth of remnants of Malassez cells involved in the development of the dental organ. Clinically, radicular cysts are difficult to diagnose. Histologic diagnosis is of primary importance in order to definitely discriminate the different kinds of periapical lesions. In this paper, the clinical, radiographic, etio-physio-pathological and microscopic features of these pathological formations are described. A case of a large radicular cyst and a case of residual cyst are reported and the surgical treatment and histologic differential diagnosis are presented.
Abstract: Bone augmentation for implant dentistry has become a necessary procedure for a number of edentulous patients. Calvarial bone grafting constitutes an important tool in achieving maxillary augmentation and sinus elevation. Much effort has been directed toward improving graft survival and volumetric maintenance. The purpose of the present study was to evaluate the histologic results of the calvarial onlay graft for maxillary reconstruction before implant placement. Two patients underwent maxillary augmentation using autogenous calvarial onlay grafts. After a 4-month healing period, biopsies of the augmented regions were performed and implants were placed. The implants were loaded after 5 months and then clinically examined after 15 months of function. Biopsies showed that calvarial onlay grafts were well incorporated into the preexisting bone after a 4-month period. Histologic and histomorphometric findings demonstrated a living bone that showed features characteristic of mature and compact osseous tissue. The restored Implants were stable and osseointegrated after a 15-month period of follow-up. The use of calvarial onlay grafts can be a predictable and successful method to achieve maxillary augmentation, allowing appropriate placement of implants and stable prosthetic restorations.
Abstract: Pulp inflammation in restored teeth is mainly due to the presence of bacteria or bacterial products introduced by microleakage around the restoration or to the material toxicity. Recent knowledge has permitted a precise identification of the risks for pulpal irritation associated with adhesive materials and procedures. The purpose of this work was to evaluate the cellular events that occur in direct pulp exposure capped using different materials. Twenty-four vital teeth without caries, scheduled for extraction for orthodontic reasons, were selected. After a control of the hemostasis, each pulp was directly capped with a different material. The samples were randomly divided into four groups of six specimens each: group I: dental-bonding agent (Solist) followed by resin composite (Ecusit); group II: dental adhesive (Prompt) and resin composite (Pertac II); group III: traditional calcium hydroxide (Dycal) plus resin composite (Ecusit); group IV: light-curing calcium hydroxide (Ultrablend Plus) and amalgam (Dentsply). After 15 days the teeth were extracted, immediately fixed in 10% buffered formalin, embedded in resin (7200 Technovit), and prepared for thin ground sections with Precise 1 System. In the specimens of all groups, there were active odontoblasts near the composite resins and no newly formed dentin. Small quantities of inflammatory cells were present. A 1- to 3-microm layer zone of necrosis was present. In conclusion, all materials tested in this study induced similar tissue responses.
Abstract: PepGen P-15 is a combination natural anorganic bovine-derived hydroxyapatite matrix (ABM) coupled with a synthetic cell-binding peptide (P-15). This material has been reported to enhance bone formation in periodontal osseous defects. The aim of this study was to assess the effect of ABM/P-15 on the healing of cortical bone defects in rabbits. Five New Zealand rabbits were used. Two 8-mm bone defects were created in each tibia. Eight defects were filled with PepGen P-15, 8 defects with PepGen P-15 Flow, and 4 defects were used as a control group. A total of 20 defects were created. All rabbits were killed at 4 weeks. Block sections containing the defects were retrieved and the specimens processed for light microscopy examination. Newly formed bone was present in both test groups, whereas, in the control-group, only a scarce quantity of newly formed bone was present and the cortical defects had not been filled by the regenerated bone. Statistical evaluation showed that there were statistically significant differences between control sites and sites treated with P-15 and P-15 Flow (P = 0.0001), and also between sites treated with P-15 and P-15 Flow (P = 0.0001), respectively. No acute inflammatory infiltrate cells were visible in both of these groups. Both PepGen P-15 and PepGen P-15 Flow enhanced new bone formation in the cortical drilled defects, whereas control defects showed very little newly formed bone.
Abstract: BACKGROUND: Calcifying odontogenic cyst (COC) is a rare lesion representing about 1% of jaw cysts. It may occur in a central (intraosseous) or peripheral (extraosseous) location. METHOD: A case of peripheral COC located on the gingiva, appearing as a painless, circumscribed, pink nodule has been reported. RESULTS: Peripheral, in contrast to central, COC tends to affect older patients. Peripheral COC is a less aggressive lesion than the central counterpart, and a simple excision biopsy is curative. CONCLUSION: The histological finding of a keratinized epithelium rich in ghost cells has helped in making the diagnosis.
Abstract: Autologous bone is the preferred bone graft material because it carries proteins as bone-enhancing substrates, minerals, and vital bone cells. Calcium sulfate (CS) is a well-tolerated, biodegradable, osteoconductive bone graft substitute and is a reasonable alternative to autogenous bone graft. Blood vessels are an important component of bone formation and maintenance. The process of vascular induction is called angiogenesis, and it plays a key role in all regenerative processes. Bone tissue differentiation is related to the local presence of blood vessels. One method to evaluate the presence of blood vessels in a tissue is to count the microvessels to evaluate microvessel density (MVD). The aim of the present study was to conduct a comparative evaluation of microvessel density in sites treated with CS and autologous bone in rabbits, with or without e-PTFE nonresorbable membranes (Gore-Tex, Flagstaff, Ariz). Nine New Zealand rabbits, each weighing about 2.5 kg, were used in this experiment. Three 6-mm wide defects were created in each tibial metaphysis. The defects were filled in a random way. The defects of group 1 (3 rabbits) were filled with CS granules (Surgiplaster, Classimplant, Rome, Italy) and covered with e-PTFE membranes. The defects in group 2 (3 rabbits) were filled with CS granules (Surgiplaster). The defects in group 3 (3 rabbits) were filled with autologous bone. A total of 54 defects were filled (18 with CS and e-PTFE membranes, 18 with CS alone, and 18 with autologous bone). No postoperative deaths or complications occurred. All nine animals were sacrificed at 4 weeks. MVD results were as follows: in the first group, 9.88 +/- 4.613; in the second group, 7.92 +/- 1.998; and in the third group, 5.56 +/- 1.895. P = .000 was highly significant. Statistically significant differences were found between groups 1 and 3, 1 and 2, and 2 and 3. The presence of more blood vessels in the sites treated with CS could help to explain the good results reported in the literature with the use of CS.
Abstract: Amelogenins represent the major component of the organic matrix of enamel, and consist of several intact and degraded forms. A precise knowledge of their respective distributions throughout the enamel layer could provide some insight into their functions. To date, no antibody exists that can selectively detect the secretory forms of amelogenin. In this study we used the chicken egg yolk system to generate an antibody to recombinant mouse amelogenin. Immunoblots of whole homogenates from rat incisor enamel organs and enamel showed that the resulting antibody (M179y) recognized proteins corresponding to the five known secretory forms of rat amelogenin. Immunogold cytochemistry demonstrated that reactivity was restricted to ameloblasts and enamel. Secretory forms of amelogenin persisted in significant amounts throughout the enamel layer. The density of labeling was highest over the surface portion of the enamel layer, but enamel growth sites in this region showed a localized paucity of gold particles. Immunoreactivity was lowest over the mid-portion of the layer and increased moderately near the dentino-enamel junction. These results indicate that intact forms of amelogenin probably have a more complex distribution in the enamel layer than was heretofore suspected.
Abstract: BACKGROUND, AIMS: Liposarcoma is the 2nd most frequent soft tissue sarcoma in adults, but it is extremely rare in the head and neck and, particularly, in the oral cavity. We report on a 25-year-old female who presented with a periodontal mass, extended from the right upper 3rd molar to the right upper 2nd premolar, covered by intact oral mucosa. The clinical differential diagnosis included peripheral giant cell granuloma, salivary gland neoplasms, squamous cell carcinoma of the gingiva, sarcoma and malignant lymphoma. METHODS: To accurately plan subsequent treatment, an excisional biopsy was performed and a myxoid liposarcoma was diagnosed. Consequently, the patient underwent wide excision of the neoplasm with maxillary en-block resection. RESULTS: The post-operative course was uneventful and the patient is alive and well 8 years after the original diagnosis. The authors stress the importance of considering soft tissue sarcomas in the diagnostic approach to patients with unusual periodontal neoplasms and to plan adequate surgical sampling of the lesion (i.e. excisional biopsy). CONCLUSIONS: This appears of pivotal importance as more limited specimens may result in inaccurate pre-operative diagnosis.
Abstract: At the beginning of the maturation stage of amelogenesis, ameloblasts deposit a basal lamina (BL) at the interface between their apical surface and maturing enamel. This structure is rich in glycoconjugates and is proposed to exhibit adhesive and/or filtering functions. To clarify its role, we have applied a recently developed surgical window model to locally administer tunicamycin (TM), an antibiotic that interferes with N-glycosylation, in the rat hemimandible using an osmotic minipump. Male Wistar rats were infused with either TM or saline as a control. Lectin-gold cytochemistry was performed to reveal glycoconjugates in the BL. Immunogold labeling of enamel proteins and albumin was carried out to verify whether depletion of N-linked sugars in the BL affects the content and distribution of endogenous and exogenous proteins in the enamel layer. Under the influence of the drug, the BL became irregular and exhibited alterations in structural organization and composition. The number of Helix pomatia agglutinin binding sites was not significantly affected but their distribution was altered. The labeling density of wheat germ agglutinin over the BL was slightly reduced. Immunoreactivity for enamel proteins showed only a small decrease, but that of albumin, both between ameloblasts and within the enamel layer, increased significantly. No structural alterations were observed in the contralateral incisor and in other sampled tissues and organs. These results demonstrate that it is possible to achieve a localized administration of TM without systemic side effects and lend support to the proposal that the BL represents a specialized structure with filtering functions.(J Histochem Cytochem 49:165-176, 2001)
Abstract: BACKGROUND: Current literature shows that calcium sulfate can be used in guided tissue regeneration. Its biocompatibility and resorbability give it significant advantages in the treatment of periodontal and endodontic defects. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change, beyond that achieved with debridement alone, in treating intraosseous defects. The aim of the present investigation was to evaluate the clinical results obtained with autologous bone plus calcium sulfate, and to compare them with the results obtained using autologous bone plus membrane. METHODS: A total of 12 patients were treated in the present investigation. A split-mouth design was utilized. Twelve 3-wall periodontal defects were treated with calcium sulfate plus autologous bone graft (test) and compared with 12 contra-lateral defects treated with a bioabsorbable membrane plus autologous bone graft (control). Before the surgical procedure, patients were instructed about oral hygiene and scaling and root planing (SRP) was completed. Probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded at baseline and 6 months. RESULTS: There were no statistical differences between test and control defects at baseline. BOP was 58% and 50% for control and test defects, respectively. Mean PD was 7.75+/-0.96 mm (control) and 8.0+/-1.28 mm (test). Mean CAL was 8.58+/-1.31 mm (control) and 8.83+/-0.91 mm (test). At 6 months, mean PD was 3.41+/-0.51 (P = 0.0022) for control defects and 3.58+/-0.51 (P = 0.0022) for test defects. CAL showed a mean gain of 5+/-0.85 for controls (P = 0.0022) and 5.25+/-0.75 for test defects (P = 0.0022). Thus, there was a mean reduction of PD of 4.33 mm (56%) for control sites and 4.42 mm (55%) for test sites. The mean clinical attachment gain was 3.57 mm for control sites and 3.58 mm for test sites. As there were no sham-operated controls, it is not clear that the healing of these test or control-treated sites was any better than similar 3-walled defects sham operated. CONCLUSIONS: Both therapies led to short-term improvement of the measured parameters; neither was superior to the other.
Abstract: Calcifying epithelial odontogenic tumor (CEOT) is an uncommon, locally aggressive odontogenic tumor representing less than 1% of all odontogenic tumors. Clear cells have been described in CEOT, ameloblastomas, calcifying odontogenic cysts, lateral periodontal, and gingival cysts. It is not yet clear if the clear cell variants of the odontogenic tumors have a different biologic behavior, even if it seems that these tumors are more aggressive with an higher recurrence rate. The authors present a case of a peripheral clear cell CEOT (CCCEOT). It is a rare lesion with only 9 cases reported in the literature. The lesion was removed by excision and no recurrence was found after a 4-year follow-up.
Abstract: Peripheral ameloblastoma (PA) is a rare odontogenic tumor most common in elderly patients. They are usually solitary; red or pink granular, nodular, or papillary lesions; up to 1.5 cm in diameter; and either not resorb bone or produce a shallow erosion. Peripheral ameloblastoma should be included in the differential diagnosis of soft tissue lumps on the gingiva or edentulous alveolus.
Abstract: A 72-year-old patient underwent the placement of 2 screw-type implants. After 5 months the patient died of a massive stroke, and a block section of the portion of the mandible containing the implants was done. The specimen was treated to obtain thin ground sections. A 1- to 5-micron gap was present between the implant and the healing cover screw, and this space was filled by bacteria and calculus; bacteria were also present in the most apical portion of the hollow part of the implant. An inflammatory infiltrate was present in the connective peri-implant tissues. The spaces between all implant components (implant, abutment, and healing screw) can act as conduits and reservoirs for bacteria, which could cause inflammation of the peri-implant soft tissues. In conclusion, the histologic data from this autopsy case may help to confirm the penetration by fluids and bacteria into the internal portion of the implants, obtained from previous in vitro and in vivo studies.
Abstract: A case of an hemangioma of the mandible in a 53-yr-old female patient is presented. The lesion was removed, and no atypia or mitotic cells were found. The excision was curative, and the overall prognosis was excellent. A differential diagnosis of radiolucent periapical lesions of the mandibular symphysis is presented.
Abstract: A case of multiple idiopathic apical root resorption in a 26-yr-old female patient is presented. A review of the literature revealed that extensive idiopathic root resorption is unusual. Neither local nor systemic etiological factors were found in our case. Examination of parents and siblings did not reveal a familiar tendency. Radiographs and clinical evaluation showed a very poor prognosis for most of the teeth present in the mouth of our patient.
Abstract: Primary intraosseous salivary gland tumors are rare, with mucopidermoid carcinoma being the most frequent histotype. The authors present a case of adenoid cystic carcinoma, located in the mandibular incisor region, associated with pain. Endodontic treatment resulted in increased pain and progressive mandibular expansion. An apicoectomy was conducted, and an intraosseous adenoid cystic carcinoma was diagnosed at histological examination. The patient was treated by wide surgical resection, and is alive and well without recurrences or distant metastases 14 yr after the original diagnosis. The case presented herein calls attention to the preoperative clinical diagnosis of periapical lesions. Radiologically, focal sclerosing osteitis, cementoblastoma, cementifying and ossifying fibroma, periapical cemental dysplasia, complex odontoma, and calcifying epithelial odontogenic tumor should be considered in the differential diagnosis. In addition the unusual occurrence of salivary gland tumors in intraosseous location stresses the importance of systematic histological examination of any tissue sample obtained after endodontic procedures.
Abstract: Initially, implant surface analyses were performed on 10 machined implants and on 10 sandblasted and acid-etched implants. Subsequently, sandblasted and acid-etched implant cytotoxicity (using L929 mouse fibroblasts), morphologic differences between cells (osteoblast-like cells MG63) adhering to the machined implant surfaces, and cell anchorage to sandblasted and acid-etched implant surfaces were evaluated. Results indicated that acid etching with 1% hydrofluoric acid/30% nitric acid after sandblasting eliminated residual alumina particles. The average roughness (Ra) of sandblasted and acid-etched surfaces was about 2.15 microns. Cytotoxicity tests showed that sandblasted and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affect cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adhering to the sandblasted and acid-etched surfaces showed an irregular morphology and many pseudopodi. These morphologic irregularities could improve initial cell anchorage, providing better osseointegration for sandblasted and acid-etched implants.
Abstract: Many materials are used for sinus augmentation procedures. Anorganic bovine bone (Bio-Oss) has been reported to be osteoconductive, and no inflammatory responses have been observed with the use of this biomaterial. One of the main questions pertaining to Bio-Oss concerns its biodegradation and substitution by host bone. Some investigators have observed rapid replacement by host bone, while other researchers observed slow resorptive activity or no resorption at all. The aim of the present study was to conduct a long-term histologic analysis of retrieved specimens in humans where Bio-Oss was used in sinus augmentation procedures. Specimens were retrieved from 20 patients after varying periods from 6 months to 4 years and were processed to obtain thin ground sections. Bio-Oss particles were surrounded for the most part by mature, compact bone. In some Haversian canals it was possible to observe small capillaries, mesenchymal cells, and osteoblasts in conjunction with new bone. No gaps were present at the interface between the Bio-Oss particles and newly formed bone. In specimens retrieved after 18 months and 4 years, it was also possible to observe the presence of osteoclasts in the process of resorbing the Bio-Oss particles and neighboring newly formed bone. Bio-Oss appears to be highly biocompatible and osteoconductive, is slowly resorbed in humans, and can be used with success as a bone substitute in maxillary sinus augmentation procedures.
