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Rabah NEDIR

ARDENTIS Clinique Dentaire
Swiss Dental Clinics Group
Rue du Collège 3
1800 Vevey
Switzerland
rabah.nedir@ardentis.ch
Dr Rabah NEDIR, born in 1965, completed his dental degree in the University of Geneva, Switzerland in 1990. As founding partner of the board of the Swiss Dental Clinics Group, he manages an Ardentis private dental clinic and is a specialist in oral surgery. He maintains a part-time academic activity as senior lecturer at the Department of Stomatology and Oral Surgery of the University of Geneva.
In implantology, his field of research deals mainly with short implants in the posterior maxillae. He conducts and is involved in many clinical trials both in private practice and as a participant in multicenter studies. He is regularly invited for lectures and training for Straumann Education as well as for the University of Geneva.

R. Nedir obtained the specialist certificate in Oral Surgery from the Swiss Society of Stomatology and Oral Surgery (SSOS). He is diplomate of the board of European Federation of Oral Surgery Societies, ITI Fellow and Speaker.

http://www.ardentis.ch

Journal articles

2012
Marc El Hage, Simon Abi Najm, Mark Bischof, Rabah Nedir, Jean-Pierre Carrel, Jean-Pierre Bernard (2012)  Graft Shrinkage and Survival Rate of Implants After Sinus Floor Elevation Using a Nanocrystalline Hydroxyapatite Embedded in Silica Gel Matrix: A 1-Year Prospective Study.   Implant Dentistry 22: 213-219  
Abstract: OBJECTIVES: The aims of this study were (1) to evaluate the vertical shrinkage percentage of nanocrystalline hydroxyapatite embedded in silica gel used for maxillary sinus floor elevation (SFE) and (2) to determine the survival rate of the implants 1 year after placement in the healed grafted sinuses. MATERIALS AND METHODS: Eleven maxillary sinuses were augmented in eight patients with NanoBone. After a healing period averaging 14.42 months, 19 implants were placed and followed up with clinical and radiographic evaluation. Panoramic radiographs were taken immediately after SFE and at 12 months after grafting. Measurements of changes in height were made by a computerized measuring technique using an image editing software. RESULTS: The mean graft height shrinkage percentage at 12 months after surgery was 8.84% (±5.32). One implant was lost before loading. All the 18 remaining osseointegrated implants received the prosthetic rehabilitation and were controlled after 3 months of functional loading. The implant survival rate at the 1-year interval was 94.74%. CONCLUSIONS: A 100% NanoBone alloplastic graft used in lateral SFE procedures presented limited height shrinkage. Implants placed in these grafted sinuses showed survival rates similar to those found in published data. These results should be interpreted cautiously considering the study's reduced sample size.
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2011
G Gallucci, L Grütter, R Nedir, M Bischof, U C Belser (2011)  Esthetic outcomes with PFM and all-ceramic single-implant crowns: a randomized clinical trial.   Clin Oral Implants Res 22: 62-69  
Abstract: OBJECTIVES: the aim of this randomized-controlled clinical trial was to compare the objective and subjective esthetic outcomes of two types of screwed-retained single-implant crowns. MATERIALS AND METHODS: participants were randomly assigned to the test (all-ceramic) and control [porcelain-fused-to-ceramic (PFM)] groups and were seen under investigation at baseline (B), crown insertion (CI), 1-year follow-up (1Y), and 2-year follow-up (2Y). Objective parameters were assessed by an intra-oral digital photograph (1:1 ratio), a study cast, a standardized radiograph, periodontal/peri-implant measurements, and questionnaires were obtained for the subjective parameters. In addition, pink esthetic score (PES) and white esthetic score (WES) were calculated for both groups. For the subjective evaluation, a visual analogue scale (VAS) questionnaire was used to assess the level of patient satisfaction regarding the esthetic outcome. Then, nine expert clinicians visually inspected and assessed subjective evaluation at the professional level. Statistical analysis was used to compare between groups and investigational appointments. RESULTS: twenty patients were included in the study, 10 allocated to the all-ceramic group and 10 to the PFM group. No statistically significant differences were observed for the objective measurements comparing the test and control groups. Minor chipping of the ceramic veneering material was observed in the two patients of control group. The mean difference for all groups comparing objective parameters revealed an increase of papilla height between time points. A slight recession (0.26 mm) of the peri-implant mucosal margin at the implant site was observed between 1Y and 2Y. Mean values for PES and WES were 13.9 and 13.1 for the PFM group and for the all-ceramic group, respectively. These values were not statistically significant. Implant crown volume, outline, translucency, and characterization showed major discrepancies with the contra-lateral natural teeth. As for subjective parameters, VAS patients' responses regarding their perceptions of the esthetic outcome showed no statistical differences between groups and clinicians' accuracy scores were 50% and 47% for PFM and all-ceramic crowns, respectively. CONCLUSION: PFM and all-ceramic single-implant restorations may be indistinguishable from each other regarding the objective/subjective assessment of esthetic integration. The material chosen for fabricating an implant crown per se does not ensure an optimal esthetic outcome if other esthetic parameters are not present.
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2010
Rabah Nedir, Nathalie Nurdin, Lydia Vazquez, Serge Szmukler-Moncler, Mark Bischof, Jean-Pierre Bernard (2010)  Osteotome sinus floor elevation technique without grafting material: A five-year prospective study.   J Clin Periodont 37: 1023-1028  
Abstract: Aim: To evaluate the long-term stability of peri-implant bone formation following implant placement without grafting into resorbed posterior maxillae. Materials and Methods: Twenty-five implants of 10 mm were placed in 17 patients to rehabilitate atrophic maxillae by means of an osteotome sinus floor elevation (OSFE) procedure without grafting. Mean residual bone height was 5.4±2.3 mm. Bone levels were evaluated at 1, 3 and 5 years using periapical radiographs. Results: All implants fulfilled survival criteria and gained peri-implant bone (mean increase 3.2±1.3 mm). Implant protrusion into the sinus decreased from 4.9±1.9 mm after surgery to 1.5±0.9 mm after 5 years. Mean crestal bone loss amounting to 0.8±0.8 mm stabilized over the 5-year observation interval. Twenty implants showed additional peri-implant bone gain following the 1-year control. Conclusions: Implant rehabilitation of atrophic maxillae may be greatly simplified using implants of less than or equal to 10 mm and the OSFE technique without grafting. Grafting material is not needed to gain at least 3 mm of bone in the atrophic maxilla. The procedure appears predictable with favourable long-term results.
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Serge Szmukler-Moncler, Mark Bischof, Rabah Nedir, M Ermrich (2010)  Titanium hydride and hydrogen concentration in acid etched titanium and titanium alloy implants: A comparative analysis of 5 implant systems.   Clin Oral Implants Res 21: 944-950  
Abstract: Abstract Objectives: Acid etching is a popular method to texture the surface of dental implants. During etching, the titanium oxide protective layer is dissolved and small native hydrogen ions diffuse into the unprotected implant surface. They enrich the implant surface with hydrogen and precipitate into titanium hydride (TiH). The aim of this study was to measure the concentration of TiH at the implant surface and the total concentration of Hydrogen at five commercially available implant systems, made of either commercially pure (cp) titanium or titanium alloy. Material and methods: X-Ray diffraction (XRD) was conducted on each implant system to determine the compounds present at the implant surface. Following a TiH(2)/Ti calibration curve, the concentration of TiH was determined. Concentration of hydrogen in the implants was measured by the inert gas fusion thermal conductivity/infrared detection method. Results: XRD data showed that TiH was present on all cp titanium implants but not on the alloyed implants. TiH concentration varied between 5% and 37%. Hydrogen concentration varied between 43 and 108 ppm, no difference in uptake was found between the cp titanium and alloyed implants. Low solubility of hydrogen in alpha-titanium is responsible for precipitation into TiH. Stronger etching conditions led to higher concentration of TiH2-x. Conclusion: High solubility of hydrogen in the beta-phase of the alloy is preventing hydrogen from precipitating into TiH. All implants, even those lacking TiH at the surface, were enriched with hydrogen. In all implants, hydrogen concentration was within the normative limit of 130 ppm.
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Hamasat Gheddaf-Dam, Semaan Abi Najm, Stella Lysitsa, Mark Bischof, Rabah Nedir (2010)  X-ray evaluation at 5-6 years of Straumann implants (part 1)   Med Buccale Chir Buccale 16: 1. 23-43  
Abstract: The loss of bone around implants is, on an average, below 1 mm during the first year and 0.2 mm per year in the years that follow. It essentially depends upon biomechanical factors but the level at which the bone stabilizes is determines by the implant depth. Intraoral radiographs (paralleling technique) are considered as the "firs choice2 for the evaluation of the radiolucency with respect to the proximal peri-implant bone. This study was based on 528 implants placesd in private practice, with an objective to determine their success rate and their survival at 5-6 years, to evaluate the peri-implant proximal bone loss and outline the factors that could influence this bone loss. The results obtained from 411 accessible patient files are in accordance with the literature date (at 5-6 years, the survival rate is 99.2%, the success rate is 93%, the average bone los sis 1.16 mm). The bone loss was more severe in smokers and in implants with a TPS surface, those placed in the anterior regions or those with vestibular cortical bone below the 1 mm. Short implants were not associated with a more severe bone loss than longer implants.
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2009
Rabah Nedir, Mark Bischof, Lydia Vazquez, Nathalie Nurdin, Serge Szmukler-Moncler, Jean-Pierre Bernard (2009)  Osteotome sinus floor elevation technique without grafting material: 3-year results of a prospective pilot study.   Clin Oral Implants Res 20: 7. 701-707 Jul  
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.
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Rabah Nedir, Nathalie Nurdin, Serge Szmukler-Moncler, Mark Bischof (2009)  Osteotome sinus floor elevation technique without grafting material and immediate implant placement in atrophic posterior maxilla: report of 2 cases.   J Oral Maxillofac Surg 67: 5. 1098-1103 May  
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.
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Rabah Nedir, Nathalie Nurdin, Serge Szmukler-Moncler, Mark Bischof (2009)  Placement of tapered implants using an osteotome sinus floor elevation technique without bone grafting: 1-year results.   Int J Oral Maxillofac Implants 24: 4. 727-733 Jul/Aug  
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.
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2007
Thomas W Oates, Pilar Valderrama, Mark Bischof, Rabah Nedir, Archie Jones, James Simpson, Helge Toutenburg, David L Cochran (2007)  Enhanced implant stability with a chemically modified SLA surface: a randomized pilot study.   Int J Oral Maxillofac Implants 22: 5. 755-760 Sep/Oct  
Abstract: PURPOSE: Chemical modification to a sandblasted, large-grit, acid-etched (SLA) implant surface has been shown to enhance the rate of osseointegration. The goal of the present study was to examine changes in stability for implants with a chemically modified SLA surface and to compare their outcomes to those of control implants. MATERIALS AND METHODS: A randomized controlled trial was conducted with 31 patients. Each patient received 2 implants with the same physical properties but with surfaces that were chemically different. The control implants had a standard SLA surface, while the test implants had a chemically modified surface. Resonance frequency analysis was assessed weekly over the first 6 weeks following implant placement. RESULTS: All implants proved clinically successful, allowing for restoration. Most implants were placed in the mandible (50 of 62). A shift in implant stability from decreasing stability to increasing stability (P < .001), occurred after 2 weeks for the test implants and after 4 weeks for the control implants. CONCLUSION: The findings from this pilot study provide clinical support for the potential for chemical modification of the SLA surface to alter biologic events during the osseointegration process and demonstrate levels of short-term clinical success similar to those observed for implants with an SLA surface.
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Rabah Nedir, Mark Bischof, Ollivier Pujol, Raymond Houriet, Jacky Samson, Tommaso Lombardi (2007)  Starch-induced implant periapical lesion: a case report.   Int J Oral Maxillofac Implants 22: 6. 1001-1006 Nov/Dec  
Abstract: This paper reports an implant periapical lesion (IPL) with a previously unreported etiology. The presence of an osteolytic area around the apex and around the middle portion of a stable Straumann hollow-screw implant was found on periapical radiographs 3.5 years after implant placement. Case management involved curettage of the soft tissue surrounding the implant apex as well as resection of the nonosseointegrated portion of the implant. Histopathologic examination revealed a connective fibrous tissue containing a dense chronic inflammatory infiltrate with a foreign-body material. Polarized light microscopy and Fourier transform infrared microspectroscopy identified the foreign-body material as starch particles. Etiology of this IPL was thus related to a foreign-body reaction to starch particles. This exogenous contamination probably originated from starch-coated gloves during the surgical procedure. This case report suggests that IPL may successfully be treated by debridement and implant resection instead of implant removal. Peri-implant apical soft tissue should be systematically submitted for histopathologic examination.
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2006
T Lombardi, M Bischof, R Nedir, D Vergain, C Galgano, J Samson, R Küffer (2006)  Periapical central giant cell granuloma misdiagnosed as odontogenic cyst.   Int Endod J 39: 6. 510-515 Jun  
Abstract: AIM: To present the clinicopathological features of a series of four periapically located central giant cell granulomas (CGCGs) that were misdiagnosed and treated as being of endodontic origin. SUMMARY: Four cases of periapical CGCGs were submitted with a clinical diagnosis of either radicular or residual cyst. In two cases, root canal treatment had been performed previously. The patients were two women and two men whose age ranged from 31 to 85 years. Two cases were located in the mandibular premolar-molar region, and two in the anterolateral region of the maxilla. Two lesions were submitted for histological examination with a diagnosis of radicular cyst whereas the remaining two were submitted with a diagnosis of residual cyst. KEY LEARNING POINTS: Periapical giant cell lesions may be unilocular and therefore misdiagnosed as an endodontic lesion because of their radiographic similarity to an inflammatory periradicular lesion, especially if the teeth have been root filled or if the vitality is negative or doubtful. It is important to follow up the healing process of a periapical radiolucency related to a root filled tooth and, in case of persistence, to perform surgery and to submit the specimen for histological examination.
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Mark Bischof, Rabah Nedir, Simon Abi Najm, Serge Szmukler-Moncler, Jacky Samson (2006)  A five-year life-table analysis on wide neck ITI implants with prosthetic evaluation and radiographic analysis: results from a private practice.   Clin Oral Implants Res 17: 5. 512-520 Oct  
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.
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Rabah Nedir, Mark Bischof, Serge Szmukler-Moncler, Urs C Belser, Jacky Samson (2006)  Prosthetic complications with dental implants: from an up-to-8-year experience in private practice.   Int J Oral Maxillofac Implants 21: 6. 919-928 Nov/Dec  
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.
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Rabah Nedir, Mark Bischof, Lydia Vazquez, Serge Szmukler-Moncler, Jean-Pierre Bernard (2006)  Osteotome sinus floor elevation without grafting material: a 1-year prospective pilot study with ITI implants.   Clin Oral Implants Res 17: 6. 679-686 Dec  
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.
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2004
Mark Bischof, Rabah Nedir, Tommaso Lombardi (2004)  Peripheral giant cell granuloma associated with a dental implant.   Int J Oral Maxillofac Implants 19: 2. 295-299 Mar/Apr  
Abstract: A 56-year-old woman was referred for the treatment of a mandibular lesion that had been slowly increasing in size over a 6-month period. Intraoral examination revealed a reddish-purple nodule involving the attached vestibular gingiva around a machined-surface dental implant that had been placed 2 years earlier in the mandibular left second premolar region. Another implant had been placed in the mandibular left second molar region. The lesion was tender and bled easily upon tooth brushing. Radiographs showed inadequate abutment angulation. The healing caps on these 2 implants were loose and in contact with each other, preventing optimal oral hygiene. An excisional biopsy of the mass resulted in the diagnosis of peripheral giant cell granuloma. After the implants were gently curetted and scaled, they were cleaned using abrasive paste. At the last follow-up, 3 years later, there was no recurrence.
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Mark Bischof, Rabah Nedir, Serge Szmukler-Moncler, Jean-Pierre Bernard, Jacky Samson (2004)  Implant stability measurement of delayed and immediately loaded implants during healing.   Clin Oral Implants Res 15: 5. 529-539 Oct  
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.
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Rabah Nedir, Mark Bischof, Serge Szmukler-Moncler, Jean-Pierre Bernard, Jacky Samson (2004)  Predicting osseointegration by means of implant primary stability.   Clin Oral Implants Res 15: 5. 520-528 Oct  
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.
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Rabah Nedir, Mark Bischof, Jean-Marie Briaux, Stephan Beyer, Serge Szmukler-Moncler, Jean-Pierre Bernard (2004)  A 7-year life table analysis from a prospective study on ITI implants with special emphasis on the use of short implants. Results from a private practice.   Clin Oral Implants Res 15: 2. 150-157 Apr  
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.
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1999
1997
Rabah Nedir, Tommaso Lombardi, Jacky Samson (1997)  Recurrent peripheral giant cell granuloma associated with cervical resorption.   J Periodontol 68: 4. 381-384 Apr  
Abstract: A case of recurrent peripheral giant cell granuloma in a 38-year-old man is reported. The lesion was localized on the attached gingiva of the lower left second premolar (tooth #35). The surgical excision of the lesion revealed a superficial resorption of the cervical region of the involved tooth. The resorption was smoothed out, and there was no sign of recurrence or further resorption after 14 months. Root resorption, although extremely rare, may be associated with peripheral giant cell granuloma.
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Conference papers

2011
2010
R Nedir (2010)  Prospective clinical study of osteotome sinus elevation in the severely resorbed maxilla.   In: Congress Report ITI World Symposium:21-22. April 15. – 17. 2010 Geneva, Switzerland  
Abstract: The posterior maxilla is still a challenging area and one of the most common sites for augmentation procedures. Rough-surfaced implants have improved the success rates, with further improvements by 22 chemically modified surfaces. Tapered Effect (TE) implants are also well suited to the posterior maxilla. However, there is no consensus as to what the best graft material is, or whether graft material is actually required. In this investigation, the 1-year viability of osteotome sinus floor elevation with short TE implants, with or without bone grafting, was evaluated. Residual bone height, endosinus bone gain and crestal bone loss were measured. Tooth extraction was performed at least 4 months prior to surgery, and the residual bone height was ≤ 4 mm. In 12 patients, 37 implants were placed in 37 sites (20 with graft material and 17 without graft material) and loaded after 10 weeks. Similar results were observed after 8 weeks for both the grafted and non-grafted sites. After 1 year, however, more of a dome shape was seen radiographically at the grafted sites. ‘Spinner’ implants were found after 8 weeks in some patients, which were loaded after a further 3 months of healing. There were two implant failures after 1 year. Endo-sinus bone gain was significantly better with the graft material, but there was no difference in crestal bone loss between the groups. The TE implant was thought to be relevant for achieving primary stability in a residual bone height < 4 mm. The results indicated that osteotome sinus floor elevation without grafting and with SLActive TE implants may be a good standard in the severely atrophic maxilla. Although bone gain was greater with graft material, it is not a prerequisite for new bone formation. More patients and follow-up times are warranted.
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1996

Masters theses

1996
R Nedir (1996)  Greffe de moelle osseuse et réaction du greffon contre l'hôte en médecine dentaire. - Genève : [s.n.], 1996. - 60 f. : ill. ; 30 cm.   University of Geneva  
Abstract: Analyse: La réaction du greffon contre l'hôte est une complication majeure des greffes de moelle osseuse. Ses manifestations cliniques, aiguës ou chroniques, ressemblent à celles rencontrées dans certaines affections dysimmunitaires. Souvent mortelles dans les formes sévères, elles touchent de nombreux organes ou tissus. L'atteinte de la muqueuse buccale est caractérisée par un érythème et des lésions lichénoïdes, celle des glandes salivaires entraîne une hyposialie. La GVHD aiguë ou chronique se caractérise histopathologiquement par un infiltrat lymphoïde avec exocytose, associé à des nécroses épithéliales focales; la forme chronique est aussi marquée par le développement d'une sclérose. Pendant la phase aiguë, la superposition des effets secondaires de la chimiothérapie et de la radiothérapie rend le diagnostic, tant clinique qu'histologique, difficile. Le traitement repose essentiellement sur les immunosuppresseurs. Une mise en état de la cavité buccale, éliminant tous les facteurs irritatifs et infectieux, sera réalisée systématiquement avant la greffe. Th. méd. dent. Genève, 1996 ; Méd. dent. 559. Directeur de thèse: Professeur Jacky Samson.
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