Abstract: OBJECTIVE: In a prospective pilot study, short< or =10 mm ITI-SLA implants were placed in the resorbed posterior maxilla by means of an osteotome sinus floor elevation (OSFE) procedure without grafting material. This paper presents 3-year data assessing bone-level changes around implants. MATERIAL AND METHODS: Twenty-five implants were placed in 17 patients to rehabilitate 16 molar and nine premolar sites. The mean residual bone height (RBH) was 5.4 +/- 2.3 mm. A healing period of 3-4 months was allowed before abutment tightening. Most implants (21/25) were 10 mm long, and the others were 8 and 6 mm long. At the 3-year control, endo-sinus bone gain, implant length protruding into the sinus and crestal bone loss (CBL) were measured on periapical radiographs. RESULTS: All implants fulfilled the survival criteria. Despite the absence of grafting material, implants were embedded into newly formed bone tissue. All implants gained endo-sinus bone; the mean gained bone was 3.1 +/- 1.5 mm. The residual protrusion length decreased from 4.9 +/- 2.1 to 1.8 +/- 2.1 mm. CBL was 0.9 +/- 0.8 mm. CONCLUSIONS: This study confirms that the OSFE procedure without grafting material is sufficient to create bone beyond the natural limit of the sinus. On the mid-term of 3 years, the technique was found to be predictable in the posterior maxilla when the RBH is limited. Implants gained endo-sinus bone despite the lack of grafting material. Bone gain was still improving over the first-year control. No shrinkage of the augmented area was observed.
Abstract: PURPOSE: This case report discusses 2 patients who required implant placement in the atrophic posterior maxilla to support a fixed prosthesis with the least invasive and shortest procedure. MATERIALS AND METHODS: The reference standard of care would be to perform sinus augmentation with an autologous bone graft through the lateral approach with delayed implant placement. However, in these cases, the posterior maxillas were treated with an osteotome sinus floor elevation procedure without grafting material and simultaneous placement of short, 8- and 10-mm-long, tapered implants. RESULTS: All implants achieved primary stability and were successfully loaded after 3.6 months of healing. At the 1- and 2-year follow-up visits, they were clinically stable and the final prostheses were functioning. The mean endosinus bone gain was 5.1 +/- 1.3 mm. In 1 of the patients, the implants were completely embedded in the newly formed bone and the sinus floor had been relocated apical to its previous demarcation. CONCLUSIONS: The findings from these 2 cases suggest that the osteotome sinus floor elevation procedure without grafting material, and immediate placement of tapered implants, might be applied in situations for which previously only the lateral approach was considered (at the condition that implants achieve firm primary stability). More patients and longer follow-up are warranted to investigate how reliable this technique can be when applied to the atrophic maxilla.
Abstract: OBJECTIVE: Implant treatment presumes that implants are placed in bone, without any contact with root. At ankylosed teeth, complete root removal is often invasive; subsequently, the sites require additional augmentation procedures to complete the treatment. The aim of this paper is to report on a series of five cases that have been treated with an approach that avoided extractive invasive surgery and bone damage. MATERIAL AND METHODS: The procedure consisted of preparing the osteotomy site by drilling through the root. At the end of the drilling sequence, the root fragments that were not removed were deliberately left at the osteotomy site. Their mobility was checked with a dental pick and when stable an implant was placed in contact with them. The sites were required to be asymptomatic and inflammation free. Ankylosed teeth were replaced with 13-15-mm-long Osseotite implants, four in the anterior maxilla and one in the anterior mandible. RESULTS: All implants healed uneventfully; they have been now loaded for a period of 12-42 months. On peri-apical radiographs, appearance of the bone-implant interface was similar to osseointegrated implants. The remaining root fragments were visible, in contact with the implants; no specific pathological sign could be detected. A limited resorption of dentine was found at one site after 4 years. CONCLUSION: This series of cases suggests that implants placed in contact with ankylosed root fragments might not interfere with implant integration or harm occlusal function, at least in the mid-term. More cases are warranted before this procedure might be considered as a reliable clinical option when, at ankylosed teeth, one wishes to avoid an invasive extraction surgery.
Abstract: PURPOSE: Achieving implant primary stability in poor-density bone is difficult when the available bone height is less than 6 mm. This study assesses the 1-year clinical performance of tapered implants in sites of reduced height in combination with osteotome sinus floor elevation without bone grafting material. MATERIALS AND METHODS: An osteotome sinus floor elevation procedure without grafting material was performed in the atrophic posterior maxilla. Tapered implants were placed in maxillary sites with residual bone height of 1 to 6 mm. Implant primary stability was assessed by finger pressure exerted on the implant. Bone gain in the elevated sinus and crestal bone loss were evaluated at 1 year via radiographs. RESULTS: Fifty-four tapered implants were placed in 32 patients and were loaded after a mean of 4.2 +/- 1.6 months. The mean maxillary residual bone height was 3.8 +/- 1.2 mm. All implants achieved primary stability, and all were successfully loaded. At the 1-year radiographic control, the mean bone gain within the sinus was 2.5 +/- 1.7 mm and the mean crestal bone loss was 0.2 +/- 0.8 mm. CONCLUSIONS: In the atrophic posterior maxilla, primary stability can readily be achieved with tapered implants, even when the mean residual bone height is 3.8 mm. Despite limited bone support and lack of grafting material, all loaded implants were clinically stable, and crestal bone loss was limited. A net bone gain of 2.3 +/- 1.8 mm was observed. Survival and success rates were 100% and 94.4%, respectively. Elevation of the sinus membrane without the addition of bone grafting material led to bone formation beyond the original limit of the sinus floor.
Abstract: The aim of this paper is to report on three patients who received unconventional implant treatment because of the presence of impacted teeth. To avoid invasive surgical removal of the impacted teeth and delayed implant treatment, implants were placed through the impacted teeth. Of the seven implants placed into four impacted teeth, all healed uneventfully except a short (8.5-mm) implant that became mobile after 4 months. One and three implants now have been loaded for 3.5 and 2 years, respectively. The two other implants were removed after 6 months of uneventful healing. These cases, although limited in number, suggest that implant placement through an impacted tooth might not interfere with implant integration or harm occlusal function, at least in the short term. More study is warranted before this unconventional procedure might be considered as a possible clinical option when, at an impacted tooth site, clinicians seek to avoid invasive surgery.
Abstract: Ultrasonic bone surgery was recently introduced as an osteotomic technique; however, documentation is scarce. This article reports on the application of ultrasonic bone surgery for 53 bone-augmentation procedures in the posterior maxilla in 34 patients over 5 years. The initial residual bone height under the sinus varied between 1 and 9 mm (mean: 3.7 mm). Distribution according to residual bone height classes was 7.7% for Class B, 39.3% for Class C, and 53.0% for Class D. The procedures included bony window opening of the sinus, cortical and cancellous bone harvesting, and activation of the sinus wall. During the sinus approach, 2 of 53 membranes (3.8%) were perforated and covered with a membrane made of platelet-poor plasma. Bone grafting was carried out with autologous bone at 22 implant sites (18.8%), with a mixture of autologous bone and anorganic bovine bone mineral (Bio-Oss) at 29 sites (24.8%), and with Bio-Oss alone at 66 sites (56.4%). The perforated membranes healed uneventfully. At second-stage surgery, four implants failed. The survival rate of the 117 placed implants was 96.6%. No implant failed after loading. Performing the sinus grafting procedure with ultrasonic bone surgery limited the occurrence of membrane perforation; by changing the tips, all surgical steps were performed safely and comfortably.
Abstract: The application of immediate loading of implants in the edentulous maxilla in multiple-risk patients is presented. Five partially edentulous patients attended with failing prostheses supported by hopeless teeth. An immediate-loading protocol was proposed because the patients rejected provisionalization with a removable prosthesis. Multiple teeth were extracted, and 44 immediately loaded implants were placed, most of them (55.5% to 88.9%) in fresh extraction sites, to support a cross-arch prosthesis that was loaded 3 to 4 days after surgery. The overall implant failure rate was 13.4%; in healed sites it was 20% (2/10) and in fresh extraction sites it was 8.82% (3/34). Prosthetic success was 100%. The overall failure rate was higher than is usually seen with the standard delayed-loading approach. Nevertheless, this immediate-loading protocol was satisfactory for the patients and the practitioner because prosthetic success was maintained during the provisionalization phase.
Abstract: PURPOSE: Evaluation of prosthetic complication was performed on 236 patients treated with 528 implants in an 8-year private practice experience. MATERIALS AND METHODS: The study sample included 55 overdentures (ODs) and 265 fixed partial dentures (FPDs). Among the latter, 231 FPDs were cemented and 34 were screw-retained. The type and frequency of prosthetic incidents were recorded, including adjustments and complications. Statistical analysis was performed using a chi-square test to identify risk factors associated with complications. RESULTS AND DISCUSSION: Over this period, 1 abut ment fractured and 2 became loose, leading to a cumulative implant component success rate of 99.2%. Patients with removable prostheses had more complications than those with fixed ones, 66.0% versus 11.5%; the difference was significant (P < .001). Posterior fixed prostheses had more complications than anterior ones, 11.0% versus 0%; however, the difference was not significant (P = .16). The complication rates for cemented and screw-retained prostheses did not differ significantly (10.4% versus 5.9%; P = .61). Prostheses with an extension cantilever had more complications, 29.4% versus 7.9%; the difference was significant (P = .01). In the OD group, the ball-retained prostheses had a significantly higher rate of complications than the bar-retained ones (77.5% versus 42.9%; P = .04). In the FPD group, complications were not recurrent; most occurred during the first 2 years, and the rate of complications did not increase with time. In the OD group, 1.3 incidents per prosthesis were recorded. Incidents were often recurrent, and the rate of complications did not decrease with time. CONCLUSIONS: Removable and fixed prostheses were associated with complications at different frequencies and of different types. In the removable group, adjustments and foreseeable complications were numerous, recurrent, and usually easy to manage. Bar-retained prostheses had fewer complications than ball-retained ones. In the fixed group, complications were limited in number and did not increase with time. Complications were restricted to the posterior region.
Abstract: OBJECTIVE: The aim of the present pilot study was to evaluate: (1) the predictability of an osteotome sinus floor elevation procedure with ITI-SLA implants without placing a bone grafting material, and (2) the possibility to gain bone height without filling the created space with a bone grafting material. MATERIAL AND METHODS: Seventeen patients received 25 implants protruding in the sinus. Most implants (21/25) were 10 mm long, eight were inserted in type 2 bone, 12 in type 3 and five in type 4 bone. At implant placement, the mean residual bone height (RBH) under the maxillary sinus was 5.4+/-2.3 mm; it was 5.7+/-2.6 mm on the mesial side and 5.1+/-1.9 mm on the distal side. Nineteen implants had less than 6 mm of bone on at least one side and six implants had less than 6 mm on both sides. A healing period of 3-4 months was allowed before abutment tightening at 35 Ncm. The percentage of stable implants at abutment tightening and at the 1-year control was calculated. The endo-sinus bone gain and the crestal bone loss (CBL) at the mesial and distal sides were measured. RESULTS: Abutments were tightened after 3.1+/-0.4 months. All implants but one (96%) resisted the applied 35 Ncm torque. At the 1-year control, all implants were clinically stable and supported the definitive prosthesis. All showed endo-sinus bone gain; the mean gain was 2.5+/-1.2 mm. The mean CBL was 1.2+/-0.7 mm. Endo-sinus bone gain and RBH showed a strong negative correlation (r=-0.78 on the mesial side and -0.80 on the distal side). A good correlation (r=0.73) was found between implant penetration in the sinus and endo-sinus bone gain. CONCLUSION: Elevation of the sinus membrane alone without addition of bone grafting material can lead to bone formation beyond the original limits of the sinus floor. Despite a limited RBH at implant placement, a healing period of 3 months was sufficient to resist a torque of 35 N cm and to lead to a predictable implant function at the 1-year control.
Abstract: This paper reports a 5-year life-table analysis on wide neck (WN) ITI implants placed in a private practice. In 212 patients, 263 implants were placed in the posterior region; 97% rehabilitated the molar area. Implants in the mandible and in the maxilla were 61.2% and 38.8%, respectively; the mean implant length was 9.7 and 8.9 mm, respectively. Eighty-nine percent sites had both vestibular and buccal bone lamellae > or =1 mm, 9.1% had one of them <1 mm and 1.9% had both lamellae <1 mm. Sinus perforation during surgery occurred in 52% of the maxillary implants. Prosthetic information was available for 249 implants; implants were involved in 157 single crowns (SC) and 80 fixed partial dentures (FPD). Radiographic analysis was performed on 102 implants that reached the 2-year control, and crestal bone loss (CBL) was measured. Results showed that five implants failed; the 5-year cumulative survival rate was 97.89%. The 1-year survival rate based on 259 implants was 98.8% and the 2-year survival rate based on 174 implants was 97.7%. In this 5-year timeframe, 94.3% of the SCs and 96.2% of the FPDs were free of complication. The mean CBL at the mesial and distal sides was 0.71 and 0.60 mm, respectively; bone losses >1 and >2 mm were recorded for 29.7% and 2.5% of the sides, respectively. This mid-term study showed that the WN ITI implants were highly predictable in private practice and that prosthetic complication in the molar area was an infrequent event.
Abstract: Ultra-sonic bone surgery (USBS) has been recently introduced as a novel osteotomic technique. This clinical study reports on the application of this new technique to perform ridge-split procedures. Over a period of 3.5 years, 57 patients underwent a split-crest procedure with the aim to place 230 implants, 78 in the mandible and 152 in the maxilla, in order to rehabilitate nine full arches, three hemi-arcades, 43 partial bridges and 24 single crowns. The initial ridge width varied between 1.5 and 5 mm, average was 3.2 mm. The final width of the ridge ranged from 4 to 9 mm, average was 6 mm. The split length varied between 4.5 and 40 mm, average was 15 mm. Inserted implants were 3.25-5 mm in diameter however most of them (82.4%) were standard implants of 3.75 mm; implant length was classically 10-13 mm. Two hundred and twenty-eight (99.1%) out of the 230 planned implants were placed, the two non-suitable sites were in the maxilla. In the mandible, the ridge augmentation procedure was drastically eased by performing a basal longitudinal discharge notch. At second stage surgery, eight implants failed to osseointegrate; the success rate for the placed implants was 96.5%. All implants have been loaded for at least 2 months and no implant was lost after loading. One hundred and eighty-one and 77 implants have been loaded for at least 6 and 12 months, respectively. The 3-year life-table analysis of loaded implants showed a cumulative survival rate of 100%. The split-crest procedure performed with USBS showed to be safe and comfortable.
Abstract: PURPOSE: This article provides preliminary clinical results on the Osseotite NT implant, which was developed to simplify surgical procedure and cover an extended range of indications. Placement characteristics of NT and standard Osseotite implants were also compared in an in vitro study. MATERIALS AND METHODS: The in vitro placement characteristics of NT and standard Osseotite implants of 4.0 mm diameter and 8.5 to 15 mm in length were compared. In addition, a total of 182 NT implants (96 maxillary and 86 mandibular) were placed in 92 patients; of these, 87.9% were placed using a 1-stage technique. The implants were placed in healed sites (43.9%), fresh extraction sockets (37.4%), or recent extraction sites (2 months postextraction) (18.7%). Before restoration, healing times of 3 to 4 months in the mandible and 5 to 6 months in the maxilla were allowed. The entered implant length in the osteotomy site before contacting the bony walls (EILOS) was compared, as well as the number of turns and the time required to seat the implants. Cumulative survival rates (CSRs) were calculated for up to 18 months of follow-up after surgery. RESULTS: The EILOS was between 47.3% and 57.6% of implant length for the NT implants; for the standard implants, it was between 12.0% and 21.2%. With the NT implants, the number of turns and the placement time were reduced by 61% to 64% and 61% to 65%, respectively. In the clinical study, 4 implants failed during the healing period; none failed after prosthesis placement. The CSR was 97.79% for implants placed into fresh or recent extraction sites; in healed sites, the CSR was 98.75%. The cumulative prosthetic success rate was 100%. DISCUSSION: This new implant design is seated with special drills; the drilling sequence requires less time and less torque than that used for standard implants. The low failure rate after prosthetic loading was consistent with that observed for standard Osseotite implants. CONCLUSION: These preliminary data suggest that the NT implant can be predictable in healed sites and fresh or relatively recent extraction sockets.
Abstract: Surface texturing by acid etching has recently become popular among dental implant manufacturers. The aim of this study was to compare the surface topography of four implant systems and to check the reproducibility of the industrial process of each implant system. Three implants per system have been selected from three distinct batches. They were observed under a scanning electron microscope (SEM), and roughness was determined with a contact profilometer by measuring five height-descriptive parameters (Ra, Rq, Rz(ISO), Rt, and Rsk, a texture parameter Sm, and a hybrid parameter RDeltaq. The analysis showed that each implant system displayed a distinct surface topography that could not be mistaken. When sandblasting was performed prior to etching, surface topography was a combination of macro- and microroughness. The roughness and the amount of remaining sand varied among the batches, showing that the industrial process is not fully developed. Deviation from the released technical information was found for two out of four implant manufacturers. Based on the available biological and clinical data on textured surfaces, it is suggested that it is bone interlocking at the interface that maintains the biological properties of textured surfaces, rather than a strong implant fixation per se.
Abstract: The SLA (sandblasted with large grit and acid etched) surface is a textured surface that has been documented to lead to a rapid and strong implant fixation. The purpose of the present study was to determine the contribution of sandblasting in addition to etching to implant anchorage. It was also aimed to determine if the pits carved during etching alone have a bone-interlocking capacity that leads to microanchorage between the implant and bone. SLA implants and machined-and-acid-etched (MA) implants were placed in the maxilla of Land Race pigs. After 10 weeks of healing, they were reverse torqued. The reverse torque of the SLA and MA implants was 157.29 +/- 38.04 N cm and 105.33 +/- 25.12 N cm, respectively. Sandblasting increased bone anchorage by 49.3%; the difference was statistically significant (p =.028). Bone was found attached to both surfaces; bone ingrowth was found in the pits of both surfaces. It is suggested that the two surfaces are able to generate bone interlocking and mechanical coupling at the interface. When finite-element modeling is performed with these surfaces, it is suggested that the bound mode be used instead of the slip mode.
Abstract: This paper reports on a 7-year life table analysis on ITI titanium plasma-sprayed (TPS) and sandblasted and etched (SLA) implants placed in a private practice and loaded for at least 1 year. In 236 patients, 528 (264 TPS and 264 SLA) implants were placed, 351 (66.5%) implants rehabilitated the posterior region and 71.1% implants were < or =11 mm. In the posterior mandible and maxilla, the mean implant length was 9.90 and 9.74 mm respectively. Implant length was determined through standard radiographs only. Increase of the number of implants or reduction of the width or length of the rehabilitations was no specifically sought for the shorter implants. One hundred and twenty-two SLA implants were loaded within 63 days. All early loaded SLA implants resisted the applied 35 N cm without rotation or pain. Three implants failed, one early and two late failures, all were SLA implants placed in the mandible. Shorter implants did not fail more than longer ones. The cumulative success rate was 99.40%. The predictable use of short implants supporting single crowns and small fixed partial dentures of 2-4 units supported by two to three implants permitted (1) restricting the need for sophisticated and expensive presurgical procedures aimed to determine precisely the available bone height by computerized radiographic methods, (2) the placement of prosthetically driven restoration instead os surgically driven ones, (3) reducing the indications span for complex invasive procedures like sinus lift and bon grafting procedures, (4) facilitating the surgery, without attempting to place the longest implant and (5) avoiding the occurrence of sensation disturbance. The safe use of short implants in a private practice should make implant therapy simpler and accessible to a higher number of patients and practitioners.
Abstract: The purpose of the present clinical study was (1) to evaluate the Osstell as a diagnostic tool capable of differentiating between stable and mobile ITI implants, (2) to evaluate a cut-off threshold implant stability quotient (ISQ) value obtained at implant placement (ISQitv) that might be predictive of osseointegration, (3) to compare the predictive ISQitv of immediately loaded (IL) implants and implants loaded after 3 months (DL). Two patient groups were enrolled, 18 patients received 63 IL implants and 18 patients were treated with 43 DL implants. The ISQ was recorded at implant placement, after 1, 2, 4, 6, 8, 10 and 12 weeks. All implants passed the 1-year loading control. Two implants failed, one DL implant with ISQ at placement (ISQi) of 48 and one IL implant with ISQi of 53. The resonance-frequency analysis (RFA) method was not a reliable diagnostic tool to identify mobile implants. However, implant stability could be reliably determined for implants displaying an ISQ> or =47. After 1 year of loading, all DL implants with an ISQi> or =49 and all IL implants with an ISQi> or =54 achieved and maintained osseointegration. By the end of 3 months, implants with ISQi<60 had an increase of stability. Implants with ISQi 60-69 had their stability decrease during 8 weeks before returning to their initial values. Implants with ISQ>69 had their stability decrease during the first 4 weeks before remaining stable. Although preliminary, these data might orient the practitioner to choose among various loading protocols and to selectively monitor implants during the healing phase.
Abstract: The purpose of the present study was (1) to measure the primary stability of ITI implants placed in both jaws and determine the factors that affect the implant stability quotient (ISQ) determined by the resonance frequency method and (2) to monitor implant stability during the first 3 months of healing and evaluate any difference between immediately loaded (IL) implants and standard delayed loaded (DL) implants. The IL and DL groups consisted of 18 patients/63 implants and 18 patients/43 implants. IL implants were loaded after 2 days; DL implants were left to heal according to the one-stage procedure. The ISQ was recorded with an Osstell apparatus (Integration Diagnostics AB, Gothenburg, Sweden) at implant placement, after 1, 2, 4, 6, 8, 10 and 12 weeks. Primary stability was affected by the jaw and the bone type. The ISQ was higher in the mandible (59.8+/-6.7) than the maxilla (55.0+/-6.8). The ISQ was significantly higher in type I bone (62.8+/-7.2) than in type III bone (56.0+/-7.8). The implant position, implant length, implant diameter and implant deepening (esthetic plus implants) did not affect primary stability. After 3 months, the gain in stability was higher in the mandible than in the maxilla. The influence of bone type was leveled off and bone quality did not affect implant stability. The resonance-frequency analysis method did not reveal any difference in implant stability between the IL and DL implants over the healing period. Implant stability remained constant or increased slightly during the first 4-6 weeks and then increased more markedly. One DL and IL implant failed; both were 8 mm long placed in type III bone. At the 1-year control, the survival rate of the IL and the DL implants was 98.4% and 97.7%, respectively. This study showed no difference in implant stability between the IL and DL procedures over the first 3 months. IL short-span bridges placed in the posterior region and full arch rehabilitation of the maxilla with ITI sandblasted-and-etched implants were highly predictable.
Abstract: PURPOSE: This article reports the preliminary data from a clinical study of immediately loaded, full-arch, screw-retained prosthesis with distal extensions (hybrid prosthesis) supported by Osseotite implants placed in the edentulous mandible. MATERIALS AND METHODS: Fifteen patients who received 103 implants were enrolled in this study. The first 2 patients received both immediately loaded and submerged implants, while the remaining patients had all implants immediately loaded. The first 9 patients received a temporary prosthesis within 4 hours of surgery, and the hybrid prosthesis, made of a titanium framework and acrylic resin teeth, was placed after 6 months. The last 6 patients received the same type of hybrid prosthesis within 36 hours of surgery. Marginal bone loss was monitored via periapical radiographs by a computerized technique. RESULTS: One failure (out of the 92 immediately loaded implants) occurred after 3 weeks of function because of infection. A cumulative success rate of 98.9% was achieved for up to 48 months of follow-up, while the prosthetic cumulative success rate for the same period was 100%. Marginal bone loss at the immediately loaded implants was within the generally accepted conventional limits for standard delayed loading protocols. DISCUSSION: This technique can reduce treatment time but should be applied with caution. CONCLUSION: The preliminary results of this study suggest that rehabilitation of the edentulous mandible by an immediately loaded hybrid prosthesis supported by 5 to 6 implants may represent a viable alternative treatment to the classical delayed loading protocols.
Abstract: The anchorage of machined Brånemark and ITI TPS-coated implants of various lengths was investigated in an animal model. Brånemark fixtures 7 and 10 mm long and ITI implants 6 and 10 mm long were inserted in the mandible of dogs and were reverse-torqued after 3 months of healing. The failing mode was different for the two implant systems. For the ITI implants, loosening coincided with the peak reverse-torque values. For the Brånemark fixtures, two reverse-torque values were identified and recorded, a 'start to rotate' and a peak value. The 'start to rotate' values for the 7 and 10 mm Brånemark fixtures were 36.67 and 38.57 Ncm, respectively, the peak values were 61.88 and 69.13 Ncm. The increase in implant length from 7 to 10 mm did not significantly improve the anchorage. The mean reverse-torque values for the 6- and 10-mm ITI implants were 104.66 and 192.25 Ncm, respectively; the difference was statistically significant. The mean removal torque of the 6-mm ITI implant was higher than the 7- and 10-mm Brånemark implants. It is suggested that the distinct anchorage magnitude and the distinct loosening patterns registered for both implant systems might be related to the various surface states. The latter might account for the different failure tendencies mentioned in the literature for short Brånemark and ITI implants.
Abstract: Immediate loading of dental implants can reduce treatment time and management concerns, thus increasing patient acceptance. This paper reports the authors' preliminary experience with partially edentulous patients having received non-occlusally loaded provisional restorations within 24 hours of surgery, compared to patients treated according to an early loading protocol. The present data suggest that implant supported fixed partial prostheses can be immediately non-occlusally loaded and restored with a predictability similar to early loaded implants.
Abstract: A growing number of clinical studies show that early (2 months) and immediate loading protocols may be predictable. However, they are based on clinical stability only The aim of this case report was to document the osseointegration status of two Osseotite implants after 2 months of healing in soft bone corresponding to type IV and subjected to two distinct mechanical environments. A completely edentulous patient received a total of 11 Osseotite implants in the mandible. Six were immediately loaded to support a provisional fixed partial denture, and five were left submerged. After 2 months, two submerged and one immediately loaded implants were retrieved and processed for histologic analysis. All immediately loaded implants were clinically stable. One histologic section per implant was obtained. All implants achieved osseointegration. The bone-implant contact was 38.9% for the submerged implant and 64.2% for the immediately loaded one. In the marrow space, both implants were covered by thin, neoformed bone trabeculae. Osseointegration can be achieved after 2 months by Osseotite implants placed in soft bone in the mandible either when immediately loaded and splinted into a provisional denture retained on six implants, or when submerged and unloaded.
Abstract: The titanium surface obtained by sandblasting and etching (SLA) is an easily alterable surface that smears and loose its typical texture. In addition, the etching process modifies the surface composition of commercially pure titanium; the latter contains titanium and an added 20-40% of titanium hydride. Therefore, the influence of a heavy surface alteration and the influence of the composition at the SLA surface, i.e. with and without titanium hydride, were investigated in vivo. Three implant groups were inserted in the mandible of Land Race pigs and left to heal during 10 weeks in a submerged way: (1). a standard SLA control group (SLAstd) with the SLA surface containing titanium hydride; (2). a test group with the SLA surface heavily altered at the thread level (SLAalt); (3). a test group with an SLA surface devoid of titanium hydride (SLAT). Sample size was n = 8. Histomorphometry analysis did not show a statistically significant difference between the control group (SLAstd: 82.12 + 6.1%), the altered surface test group (SLAalt: 86.25 + 7.4%) and the SLA without titanium hydride test group (SLAT: 75.12 + 7.6%). The data suggest that alteration of the SLA surface, if it occurs, should not be detrimental to bone response. The soft and easy smearable SLA surface might even be an advantage when surface maintenance is required. Surface composition did not play a significant role in the bone response to the SLA surface and it can therefore be concluded that the osteophilic properties of the SLA surface are due to its surface topography and not to its specific surface composition.
Abstract: A growing number of clinical reports show that early and immediate loading of endosseous implants may lead to predictable osseointegration; however, these studies provide mostly short- to mid-term results based only on clinical mobility and radiographic observation. Other methods are needed to detect the possible presence of a thin fibrous interposition of tissue that could increase in the course of time and lead to clinical mobility A histologic evaluation was performed on two immediately loaded Osseotite implants retrieved after 4 months of function from one patient. He had received a total of 12 implants in the mandible, of which six were immediately loaded and six were left to heal in a submerged way Clinical and histologic osseointegration was consistently achieved for both of the retrieved immediately loaded implants. Osteogenesis and bone remodeling on the Osseotite surface were not impeded by immediate loading as shown by histomorphometric evaluation, which revealed high levels of bone-to-implant contact ranging from 78% to 85%. This immediate loading protocol involving bilateral splinting of six Osseotite implants in the mandible proved to be successful after 4 months of loading. Further long-term clinical and histologic studies are needed before introducing this immediate loading protocol as a routine procedure in implant therapy.
Abstract: In oral implantology, a 3-6 month stress-free healing period is presently accepted as a prerequisite to achieve bone apposition without interposition of a fibrous scar tissue. This protocol was introduced by Brånemark and co-workers in 1977. The aim of the present paper is to review the reasons that led Brånemark and collaborators to require long delayed loading periods. It is shown that the requirement for long delayed loading periods was drawn from the initiation and development periods of their original clinical trial. Demanding conditions were met involving simultaneously: 1) patients with poor bone quality and quantity, 2) non-optimized implant design, 3) short implants, 4) non-optimized surgical placement, 5) non-optimized surgical protocol and 6) biomechanically non-optimized prosthesis. Extrapolation of the requirement for long healing periods from these particular conditions to more standard situations involving refined surgical protocols and careful patient selection might be questioned. Albeit premature loading has been interpreted as inducing fibrous tissue interposition, immediate loading per se is not responsible for fibrous encapsulation. It is the excess of micromotion during the healing phase that interferes with bone repair. A threshold of tolerated micromotion exists, that is somewhere between 50 microns and 150 microns. It is suggested that loading protocols might be shortened through 2 different approaches. The first way would be to decrease stepwise the delayed loading period for free-standing implants below the presently accepted 3-6 months of healing. The second way would be to identify immediate loading protocols that are capable of keeping the amount of micromotion beneath the threshold of deleterious micromotion. Immediate loading protocols for implants-retained overdentures and fixed bridges are reviewed. It is shown that successful premature loading protocols require a careful and strict patient selection aimed to achieve the best primary stability. These various protocols need to be further documented in order to assess their predictability.
Abstract: STATEMENT OF PROBLEM: Immediate loading of implants may be a predictable treatment alternative when cross-arch stabilization with a fixed provisional is observed. PURPOSE: This study investigated the effect of immediate masticatory loading on the stability of single-standing dental implants with 4 different surfaces. MATERIAL AND METHODS: A total of 40 solid screw implants (diameter 3.3 mm, length 8 mm) were placed in the mandibles of 4 beagle dogs. Test groups included 3 hydroxyapatite (HA) coatings of titanium plasma-sprayed (TPS) implants. Implants with TPS alone served as control. Gold crowns were inserted 2 days after implant placement and the dogs were immediately put on a hard food diet. Implants were followed for 6 months after loading. Clinical and radiographic assessments of implants were performed at time of crown insertion (baseline) and after 1, 3, and 6 months of loading. The Periotest instrument was used for mobility measurements and radiographs were obtained for evaluation of peri-implant radiolucency and measurement of crestal bone changes. RESULTS: Of 40 implants, 39 displayed no discernible mobility, corresponding to successful clinical function. Peri-implant radiolucencies were absent for all but the 1 mobile implant. The reduction in crestal bone levels adjacent to the implants between baseline and 6 months was statistically significant (P <.0001). No statistically significant differences in crestal bone level changes over time were found between the various coatings demonstrating the absence of a treatment effect initiated by the surface coatings. CONCLUSION: In this study in beagle dogs, immediate masticatory loading of single-standing dental implants did not jeopardize tissue integration, provided the implants had excellent primary stability.
Abstract: A significant no-load healing period is the generally accepted prerequisite for osseointegration in dental implantology. The aim of this article was to examine whether this no-load healing period is validated by the experimental literature. In vivo histological data was scrutinized to identify the effect of early loading protocols on the bone-implant interface. Several loading modes were identified. They were categorized into groups according to implant design and the type of prosthetic reconstruction, and by their ability to introduce a distinct magnitude of motion at the interface. Specific histologic responses of early loaded implants (i.e., fibrous repair or osseointegration) were suggested to be directly related to the specific combinations of the above parameters. Early loading per se was not found to be detrimental to osseointegration. Specifically, only excessive micromotion was directly implicated in the formation of fibrous encapsulation. The literature suggests that there is a critical threshold of micromotion above which fibrous encapsulation prevails over osseointegration. This critical level, however, was not zero micromotion as generally interpreted. Instead, the tolerated micromotion threshold was found to lie somewhere between 50 and 150 microns. Suggestions are made for the earliest loading time that achieves osseointegration.
Abstract: The influence of various parameters on bone heating during drilling and drilling time was studied in vitro in a bovine cortical femur model. Drilling using a standard, a surgical or a laboratory motor unit did not affect bone temperature elevation. For a given speed, low 1/40 reduction contra-angle was more effective in moderating temperature elevation when compared to 1/10 reduction; but drilling time in this case (1/40) had to be doubled. Enhancing the drilling load from 0.8 kg to 2 kg had little effect on temperature elevation at 400 rpm and 800 rpm (< 3 degrees C). Drilling time drastically decreased and was inversely proportional to the square of the load. Predrilling did not affect temperature elevation, but decreased drilling time. From 400 rpm to 10,000 rpm, temperature elevation was positively correlated with drilling speed. It further decreased up to 24,000 rpm and then was constant up to 40,000 rpm. Drilling time was proportionally reduced with increased rotation speed. Strikingly, heat was largely dissipated within 10 s at high rotation speed. The use of a cryogenic spray at 24,000 rpm allowed the reduction of temperature elevation. Finally, protection from temperature elevation according to above parameters is suggested.
Abstract: We present an investigation of the physico-chemical surface properties of commercially pure titanium coverslips which were submitted to various treatments designed to optimize their topography in view of application in oral implantology. The surface microroughness, chemical composition and water wettability were analyzed on titanium coverslips prepared by mechanical polishing, acid attack in HCl/H2SO4, after mechanical polishing or sandblasting, and titanium plasma-spray. The chemical composition has been measured by Auger electron spectroscopy. The treatments have no major influence on the surface chemical composition and all the samples display a composition approaching that of TiO2 with minor amounts of carbon, sulfur, silicon and calcium as impurities. The roughness has been measured by scanning force microscopy on an area of 20 microns x 20 microns on each sample. Polished titanium is smooth (peak-to-valley roughness 81 nm), whereas the acid-attacked surfaces exhibit a micro-roughness in the microns range (2100 nm for polished and acid attacked; 3600 nm for sandblasted and acid attacked) which is quite reproducible over large areas of the sample. The acid attacked samples present a subsurface layer which contains hydrogen below the native passivating oxide layer. Water wettability measurement shows that all surfaces are hydrophobic with a slightly higher contact angle for the acid attacked surfaces. The different treatments analyzed in this study essentially influence the surface roughness by preserving the chemical composition and the wettability properties of titanium native oxide surface layer.
Abstract: The term 'osseointegration' was coined in 1977. This term gained popularity and has been extensively used, but with various and diverging meanings; therefore, there is a strong need to redefine it. We propose a definition of the concept of osseointegration grounded on a physical basis. Since bioactive biomaterials are more strongly integrated than inert ones (e.g. titanium or alumina), and since osseointegration is a word implying strong bonding, we propose to devote the use of the concept of osseointegration for materials which are most successfully integrated into bone, i.e. when the bone/implant interface is a diffuse interface with full chemical bonding, such as for bioactive biomaterials. If the bone/implant interface is a sharp one, the concept of osseointegration is no longer relevant and we propose use of the term 'osteal integration', i.e. for inert biomaterials, such as titanium and alumina. Based on this proposition, we assert that osseointegration is not a requirement for success in implant dentistry.
Abstract: The Armatron technique permits the easy construction of single-implants controlling the proprioceptive sensitivity with the use of a natural tooth. This is an elegant solution, rather mildly disabling, with simple concept and realization. Besides, it is a non aggressive and reasonable alternative to costly solutions such as bridges on intact teeth or implants. Although simple and safe, the Armatron technique was only made possible by the use of modern materials as well as surgical tools with high definition technology which guarantee the reliability of this method.
