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Introduction: The results with shorter and shorter implants have been revolutionizing the implantology scenario and are worthy of being well-analyzed and understood. This review aims to add further knowledge about the last 10-years observation period on < 7mm-short implants in the posterior atrophic jaws, better defining the indication of their use., Methods: From a Medline database research, systematic reviews, controlled and no- controlled trials (CT, n-CT) with ≥ 3years-follow-ups on <7 mm / ≥ 5mm-short implants (group A), and clinical studies with ≥ 1year-follow-up on 4mm-short implants (group B) were considered. The outcomes, in terms of implant survival rate (SR), marginal bone loss (MBL), and complications were analyzed according to the duration of follow-ups, implant site (maxilla and mandible), type of prosthesis (single crown or splinted units), vertically impaired or normal sites., Results: Thirty-four trials (28 for group A and six for group B) were selected. Group A: a mean follow up of 5,8 (3-10) years came out; pre-and post-loading SR range was 94.4- 100% and 89.6-100%, respectively; the range of MBL was 0.12-1.49; 50% of CT found less statistically significant surgical complications in comparison with standard implants (ST) in reconstructed sites, while major prosthetic problems were recorded with short -implants (SH) in 37.5% of CT; in no atrophied sites, a mean SR range of 86.7-100 % vs. 88-100 % and a total bone loss of 2 vs.1.6 for SH vs.ST emerged. Group B: the overall mean follow-up period was 2,3 years, and the pre-and post- SR ranges were 93-100 % and 87.5-100 %, respectively. The MBL range was 0.02- 0.63 mm. All RCT reported significantly fewer surgical complications with SH than with ST in reconstructed mandibles within one year. No prosthetic complications were reported for up to 5 years using no pontics or cantilevers fixed bridges., Conclusions: Similar or even better results for SH than ST in terms of post-loading SR and MBL came out for < 7mm/ ≥ 5mm-short implants in atrophic bone regardless of the prosthetic solutions, with less surgical complications but a few more prosthetic problems; the good results up to 5 years for 4mm-short implants in mandibles are associated with splinted and no-risk prosthetic solutions., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Objectives: To evaluate the outcomes of bone regeneration using a customized titanium mesh scaffold to cover a bone graft for reconstruction of complex defects of the jaws., Materials and Methods: 19 large defects were digitally reconstructed using CT scans according to the prosthetic requirements. A titanium mesh scaffold was designed to cover the bone (autologous/bovine bone particulate) graft. At least 6 months after surgery, a new cone-beam CT was taken. The pre- and postoperative CT datasets were then converted into three-dimensional models and digitally aligned. The actual mesh position was compared to the virtual position to assess the reliability of the digital project. The reconstructed bone volumes (RBVs) were calculated according to the planned bone volumes (PBVs), outlining the areas under the mesh. These values were then correlated with the number of exposures, locations of atrophy, and virtually planned bone volume., Results: The mean matching value between the planned position of the mesh and the actual one was 82 ± 13.4%. 52.3% (40% early and 60% late) exposures were observed, with 15.8% exhibiting infection. 26.3% resulted as failures. The amount of reconstructed bone volume (RBV) in respect to PBV was 65 ± 40.5%, including failures, and 88.2 ± 8.32% without considering the failures. The results of the exposure event were statistically significant (p = .006) in conditioning the bone volume regenerated., Conclusions: This study obtained up to 88% of bone regeneration in 74% of the cases. The failures encountered (26%) should underline the operator's expertise relevance in conditioning the final result., (© 2022 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Background: In edentulous patients, bone resorption cannot allow the installation of standard implants and it is demanded to use short implants in the residual alveolar bone or longer implants in grafted bone., Aim: To compare the survival and bone level changes of standard plus short 4-mm implants used as distal support of a maxillary full-arch fixed dental prostheses (FDPs) with standard (10-mm) implants placed in association with a bilateral sinus floor augmentation procedure., Material and Methods: Full-arch FDPs supported by six implants were randomly placed in both groups. In the control group, all implants were 10 mm long and 4.1 mm in diameter. The distal implant in both sides of the maxilla was installed after 4 months from bilaterally sinus floor elevation. In the test group (short group), the distal implant in both sides of the maxilla was 4 mm long and 4.1 mm in diameter. No sinus floor elevations were performed in the test group. Clinical assessments and X-rays were taken at prosthesis delivering and after 6, 12, 18, and 24 months. Patient-reported outcome measures (PROMs) were also evaluated before surgery and after 6, 12, and 24 months., Results: The changes over time of the bone level for the short implants were -0.01 ± 0.11 mm, -0.04 ± 0.13 mm, -0.17 ± 0.29 mm, and -0.28 ± 0.37 mm after 6, 12, 18, and 24 months from prosthesis delivering, respectively. For the standard implants, bone changes were -0.21 ± 0.33 mm ( p = 0.103), -0.30 ± 0.32 mm ( p = 0.023), -0.40 ± 0.37 mm ( p = 0.144), and -0.54 ± 0.49 mm ( p = 0.128), respectively. A statistically relevant difference was found only at 12 months after loading between the two groups., Conclusions: Similar results on implant survival rate and marginal bone loss were observed for the short and standard implants, placed in association with a bilateral sinus floor augmentation procedure, used as distal support of a maxillary full-arch FDP. A statistically relevant difference was found only at 12 months after loading between the two groups ( p = 0.023).

Objectives: The aim of this study was to evaluate hard and soft tissues around implants placed in posterior mandible 1 year after vertical ridge augmentation (VRA)., Materials and Methods: 40 patients with vertical defects were enrolled and treated according to the study protocol. Patients were randomly divided into two study groups: reinforced PTFE membranes (group A) and titanium meshes plus collagen membranes (group B). All patients received simultaneous implants which were evaluated after prosthetic restoration at baseline and after 1 year, using the following parameters: peri-implant bone levels (PBLs), interproximal bone peaks (IBPs), pocket probing depth (PPD), bleeding on probing (BoP), plaque index (mPI), gingival index (mGI), keratinized tissue thickness/width (tKT and wKT), and fornix depth (FD). Statistical analysis was performed to investigate any statistically significant differences and/or correlations (p = .05)., Results: 30 patients were completely followed up according to the study protocol. After 1 year, implants showed a change in PBL from 0.12 to 0.76 mm, with marginal bone loss of 0.67 and 0.61 mm for group A and group B, respectively, without significant differences (p > .9337). The estimated difference between treatments for the change from baseline in PBL was -0.05 (95% CI -0.27 to 0.16). Statistical analysis revealed strong correlations between PBL and IBP (p < .0001). However, no significant differences were observed for PPD, mPI, mGI, tKT, wKT, and FD (p > .05)., Conclusion: The results indicate that GBR treatment with titanium meshes plus collagen membranes (Group B) compared to reinforced PTFE membranes does not appear to be inferior or superior in terms of PBL change. In both groups, hard and soft tissues were stable after 1 year of follow-up, with a peri-implant bone loss less than 1.0 mm in the first year (study registered at ClinicalTrials.gov NCT04332679)., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The use of a 2-stage inlay technique in atrophic posterior mandibles with more than 10-mm thickness and less than 5-mm height above the inferior alveolar nerve is described. The first surgical procedure was a basic corticotomy of the buccal and lingual bone. One month later, a complete inlay procedure was performed. Computed tomography and conventional radiography showed a mean vertical bone gain of 11.5 mm. This 2-stage inlay technique avoids the use of chisels to complete bone osteotomy and reduces postsurgical nerve disturbances in atrophic posterior mandibles. This technique reduces intraprocedure and postoperative patient discomfort.

Objectives: To evaluate whether 6.3 mm-long implants could be a suitable alternative to longer implants placed in vertically augmented atrophic posterior mandibles., Materials and Methods: Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on CT scans above the mandibular canal were randomised according to a parallel group design either to receive 1 to 3 submerged 6.3 mm-long implants or 9.3 mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with interpositional an organic bovine bone blocks covered by resorbable barriers. Grafts were left to heal for 5 months before implant placement. Four months later, provisional acrylic prostheses were delivered, and were then replaced after another 4 months by definitive metal-ceramic prostheses. Outcome measures were prosthesis and implant failures, complications, and radiographic peri-implant marginal bone level changes. All patients were followed up to 3 years after loading., Results: Four patients dropped out, two from each group. The augmentation procedure failed in two patients and only 6.3 mm-long implants could be inserted. There were no statistically significant differences for prosthesis and implant failures. Three prostheses could not be placed or had to be remade in the short implant group versus 4 prostheses in the augmented group. Two short implants failed versus 3 long implants, all in different patients. There were statistically significantly more complications in augmented patients (22 complications in 20 augmented patients versus 5 complications in 5 patients of the short implant group). Both groups gradually lost peri-implant bone in a statistically significant way at 4 months, and 1 and 3 years after loading. Three years after loading, patients of the short implant group lost an average of 1.24 mm of peri-implant bone compared with 1.76 mm in the long implant group. Short implants experienced statistically significantly less bone loss (0.52 mm; CI 95% 0.20 to 0.83, P = 0.002) than long implants., Conclusions: When residual bone height over the mandibular canal is between 7 and 8 mm, 6.3 mm short implants could be an interesting alternative to vertical augmentation since the treatment is faster, cheaper and associated with less morbidity. Longer follow-ups are needed to confirm these results.

Purpose: To evaluate whether short (5 to 8.5 mm) dental implants could be a suitable alternative to longer (>11.5 mm) implants placed in atrophic maxillae augmented with autogenous bone for supporting dental prostheses., Materials and Methods: Twenty-eight patients with fully edentulous atrophic maxillae having 5 to 9 mm of residual crestal bone height at least 5 mm thick, as measured on computerised tomography scans, were randomised into two groups either to receive 4 to 8 short (5 to 8.5 mm) implants (15 patients) or autogenous bone from the iliac crest to allow the placement of at least 11.5 mmlong implants (13 patients). Bone blocks and the windows at maxillary sinuses were covered with rigid resorbable barriers. Grafts were left to heal for 4 months before placing implants, which were submerged. After 4 months, provisional reinforced acrylic prostheses or bar-retained overdentures were delivered. Provisional prostheses were replaced, after 4 months, by definitive screw-retained metal-resin cross-arch fixed dental prostheses. Outcome measures were: prosthesis and implant failures, any complications (including prolonged postoperative pain) and patient satisfaction. All patients were followed for 5 months after loading., Results: All patients could be rehabilitated with implant-supported prostheses and none dropped out. One bilateral sinus lift procedure failed due to infection, though short implants could be placed. One implant failed in the augmented group versus 2 short implants in 2 patients. All failures occurred before loading. Significantly more complications occurred in augmented patients: 8 complications occurred in 5 augmented patients (all complained of pain 1 month after bone harvesting from the iliac crest). No complications occurred in the short implant group. All patients were fully satisfied with the treatment and would do it again., Conclusions: This pilot study suggests that short implants may be a suitable, cheaper and faster alternative to longer implants placed in bone augmented with autogenous bone for rehabilitating edentulous atrophic maxillae. However, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years.

Purpose: To evaluate whether 5 mm short dental implants could be an alternative to augmentation with anorganic bovine bone and placement of at least 10 mm long implants in posterior atrophic jaws., Materials and Methods: Fifteen patients with bilateral atrophic mandibles (5-7 mm bone height above the mandibular canal), and 15 patients with bilateral atrophic maxillae (4-6 mm bone height below the maxillary sinus) and bone thickness of at least 8 mm, were randomised according to a splitmouth design to receive one to three 5 mm short implants or at least 10 mm long implants in augmented bone. Mandibles were vertically augmented with interpositional bone blocks and maxillary sinuses with particulated bone via a lateral window. Implants were placed after 4 months, submerged and loaded, after 4 months, with provisional prostheses. Four months later, definitive provisionally cemented prostheses were delivered. Outcome measures were: prosthesis and implant failures, any complication and peri-implant marginal bone level changes., Results: In 5 augmented mandibles, the planned 10 mm long implants could not be placed and shorter implants (7 and 8.5 mm) had to be used instead. One year after loading no patient dropped out. Two long (8.5 mm in the mandible and 13 mm in the maxilla) implants and one 5 mm short maxillary implant failed. There were no statistically significant differences in failures or complications. Patients with short implants lost on average 1 mm of peri-implant bone and patients with longer implants lost 1.2 mm. This difference was statistically significant., Conclusions: This pilot study suggests that 1 year after loading, 5 mm short implants achieve similar if not better results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation since the treatment is faster, cheaper and associated with less morbidity, however their long-term prognosis is unknown.

Purpose: To compare the efficacy of two different techniques for maintaining the space beneath a maxillary lining lifted using a lateral window approach: rigid synthetic resorbable barriers versus granular anorganic bovine bone., Materials and Methods: Ten partially edentulous patients having bilaterally 1 to 5 mm of residual bone height and at least 5 mm bone width below the maxillary sinuses, were randomised in a split-mouth study design, to receive a rigid Inion GTR Biodegradable Membrane System barrier without any graft on one side and 100% loosely packed granular Bio-Oss on the contralateral side following a lateral window, two-stage, sinus lift procedure. After 6 months, two or three implants were inserted at each side and submerged for 4 months. Implants were loaded with provisional acrylic prostheses and replaced, after 4 months, by definitive metal-ceramic prostheses cemented with provisional cement. Outcome measures were implant and prosthetic failures, any complication and peri-implant marginal bone level changes assessed by a blinded outcome assessor. All patients were followed up to 1 year after loading., Results: One patient dropped out after implant placement. One distal implant failed at the Inion side just before delivery of the definitive prosthesis, which was cut and maintained as a single crown. Four complications occurred in three patients at Inion sites (two sinus lining perforations, one fracture of the ceramic cusp of the definitive prosthesis, one iatrogenic peri-implantitis) versus two complications at Bio-Oss sites (one sinus lining perforation and one iatrogenic peri-implantitis). There were no differences for failures or complications between groups; however, in one of the patients where a perforation occurred at the Inion site, at implant placement, the sinus was filled two-thirds with soft tissue and the site was retreated with Bio-Oss. There were no statistically significant differences in bone loss between groups. One year after loading, Inion sides lost an average of 1.5 mm of periimplant bone and Bio-Oss sides about 1.7 mm., Conclusions: A bone graft may not be needed to augment atrophic maxillary sinuses since it is sufficient to keep space with a rigid barrier; however, it may be simpler to fill sinuses with a bone substitute than positioning a rigid barrier to maintain space.

Objectives: To evaluate whether 7-mm-long implants could be an alternative to longer implants placed in vertically augmented posterior mandibles., Materials and Methods: Sixty patients with posterior mandibular edentulism with 7-8 mm bone height above the mandibular canal were randomized to either vertical augmentation with anorganic bovine bone blocks and delayed 5-month placement of ≥10 mm implants or to receive 7-mm-long implants. Four months after implant placement, provisional prostheses were delivered, replaced after 4 months, by definitive prostheses. The outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone levels. All patients were followed to 1 year after loading., Results: One patient dropped out from the short implant group. In two augmented mandibles, there was not sufficient bone to place 10-mm-long implants possibly because the blocks had broken apart during insertion. One prosthesis could not be placed when planned in the 7 mm group vs. three prostheses in the augmented group, because of early failure of one implant in each patient. Four complications (wound dehiscence) occurred during graft healing in the augmented group vs. none in the 7 mm group. No complications occurred after implant placement. These differences were not statistically significant. One year after loading, patients of both groups lost an average of 1 mm of peri-implant bone. There no statistically significant differences in bone loss between groups., Conclusions: When residual bone height over the mandibular canal is between 7 and 8 mm, 7 mm short implants might be a preferable choice than vertical augmentation, reducing the chair time, expenses and morbidity. These 1-year preliminary results need to be confirmed by follow-up of at least 5 years., (© 2010 John Wiley & Sons A/S.)

Objective: To test if using a CAD/CAM system might reduce the necessity of bone augmentation in patients with atrophic maxillary arches before implant therapy., Method and Materials: Twenty male and female patients consecutively scheduled for bone augmentation of the jaw before implant surgery were included in this study, with a total of 29 jaws (maxillary and mandibular) to analyze for the implant-supported fixed prosthesis group and 19 maxillary arches for the implant-supported removable prosthesis group. NobelGuide System (Nobel Biocare), Autocad System (Autodesk), and routine manual CT measurements of available bone were used in this study., Results: The total results of the mean values of the fixed prosthesis group plus the mean values of the removable prosthesis group showed a statistically significant difference between the NobelGuide intervention score and both manual (P = .004) and Autocad (P = .001) measurements., Conclusions: The NobelGuide System represents a viable diagnostic device to reduce the entity or avoid bone reconstructive surgery before implant placements in the atrophic maxilla and mandible.

Purpose: To compare the effectiveness of two different techniques to lift the maxillary sinus via a crestal approach: the Summers versus the Cosci technique., Materials and Methods: Fifteen partially edentulous patients missing bilaterally maxillary molars and/ or premolars having 4 to 7 mm of residual crestal height and at least 5 mm thickness below the maxillary sinuses measured on computed tomography scans were randomised to have implants placed in sinuses crestally lifted according to the Cosci or Summers technique with bone substitutes according to a split-mouth design. Implants were left to heal submerged for 6 months. Implants were loaded with acrylic provisional crowns/prostheses. Screw-retained definitive metal-ceramic prostheses were delivered 4 months after provisional loading. Outcome measures were prosthesis and implant failures, any complications, operation time, operator preference, and patient preference assessed 1 month after surgery and 1 month after delivery of the final prostheses by a blinded outcome assessor. All patients were followed up to 5 months after loading (1 year after implant placement)., Results: Nineteen study implants were placed according to each technique. No patient dropped out and no implant failed. No discomfort/complications occurred at sites treated with the Cosci technique whereas 12 patients reported discomfort during the augmentation procedure at the side treated with the Summers technique, this was statistically significant, and in one of these patients a perforation of the sinus membrane occurred. Postoperatively, headache was reported by nine patients and swelling occurred in three of these patients at the Summers treated sides. Statistically significantly less time was required to place implants according to the Cosci technique (33 versus 24 minutes, on average). The two operators and 14 out of 15 patients preferred the Cosci technique., Conclusions: Both crestal sinus lift techniques were successful but the Cosci technique required less surgical time, produced less intra- and postoperative morbidity and was preferred by patients.

Objectives: To compare two different techniques for vertical bone augmentation of the posterior mandible: bone blocs from the iliac crest vs. anorganic bovine bone blocs used as inlays., Materials and Methods: Ten partially edentulous patients having 5-7 mm of residual crestal height above the mandibular canal had their posterior mandibles randomly allocated to both interventions. After 4 months implants were inserted, and after 4 months, provisional prostheses were placed. Definitive prostheses were delivered after 4 months. Histomorphometry of samples trephined at implant placement, prosthesis and implant failures, any complication after loading and peri-implant marginal bone-level changes were assessed by masked assessors. All patients were followed up to 1 year after loading., Results: Four months after bone augmentation, there was statistically significant more residual graft (between 10% and 13%) in the Bio-Oss group. There were no statistically significant differences in failures and complications. Two implants could not be placed in one patient augmented with autogenous bone because the graft failed whereas one implant and its prosthesis of the Bio-Oss group failed after loading. After implant loading only one complication (peri-implantitis) occurred at one implant of the autogenous bone group. In 16 months (from implant placement to 1 year after loading), both groups lost statistically significant amounts of peri-implant marginal bone: 0.82 mm in the autogenous bone group and 0.59 mm in the Bio-Oss group; however, there were no statistically significant differences between the groups., Conclusions: Both procedures achieved good results, but the use of bovine blocs was less invasive and may be preferable than harvesting bone from the iliac crest.

Purpose: To compare the efficacy of inlay and onlay bone grafting techniques in terms of vertical bone formation and implant outcomes for correcting atrophic posterior mandibles., Materials and Methods: Twenty surgical sites were assigned to two treatment groups, inlay and onlay, with iliac crest as donor site. After 3 to 4 months, 43 implants were placed and loaded 4 months later. The median follow up after loading was 18 months., Results: For the inlay versus onlay group, median bone gain was 4.9 versus 6.5 mm (p = .019), median bone resorption was 0.5 versus 2.75 mm (p < .001), and median final vertical augmentation was 4.1 versus 4 mm (p = .190). The implant survival rate was 100% in both groups, while the implant success rate was 90% versus 86.9% (p = .190, not significant). A minor and major complication rate of 20% and 10%, respectively, for both groups was encountered., Conclusions: Inlay results in less bone resorption and more predictable outcomes, but requires an experienced surgeon. In contrast, onlay results in greater bone resorption and requires a bone block graft oversized in height, but involves a shorter learning curve. Once implant placement has been carried out, the outcomes are similar for both procedures.

Purpose: To evaluate whether 7-mm-long implants could be a suitable alternative to longer implants placed in vertically augmented bone for the treatment of atrophic posterior mandibles., Materials and Methods: Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on a computed tomography scan above the mandibular canal were randomised to receive either two to three submerged 7-mm-long NanoTite External Hex implants (Biomet 3i) or 10-mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with anorganic bovine bone blocks (Bio-Oss) using a sandwich technique and resorbable barriers. The grafts were left healing for 5 months before placing the implants, which were submerged. Four months after implant placement, provisional acrylic prostheses were delivered. Definitive screw-retained metal-ceramic prostheses were delivered 4 months later. Outcome measures were: prosthesis and implant failures, any complications, and time needed to fully recover mental nerve sensitivity. All patients were followed up to the delivery of the final restorations (4 months after loading)., Results: No patient dropped out. In two patients of the augmented group, there was not enough space to place 10-mm or longer implants as planned and 7-mm-long implants were used instead. The most likely reason for this is that the Bio-Oss blocks fractured in many pieces at placement. One prosthesis could not be placed when planned in the 7-mm group versus three prostheses in the augmented group, because of failure of one implant in each patient. The difference was not statistically significant. All implants were successfully replaced and final prostheses delivered. Four complications (wound dehiscence) occurred during graft healing in the augmented group (one possibly associated with the failure of one implant) versus none in the 7-mm-long implant group. The difference was not statistically significant. No patient suffered from permanent paraesthesia of the alveolar inferior nerve; however, sensitivity was recovered significantly faster in the short implant group., Conclusions: The early results of this study suggest that, when the residual bone height over the mandibular canal is between 7 and 8 mm, 7-mm short implants might be a preferable choice since the treatment is faster, cheaper and associated with less morbidity than vertical bone augmentation. These preliminary results must be confirmed by follow-ups of 5 years or more in order to monitor the performance of short implants over time.

Purpose: To compare the efficacy, complications and patient preference of two different techniques for vertical bone augmentation of the posterior mandible: bone blocks harvested from the iliac crest versus anorganic bovine bone blocks (Bio-Oss(R)) were used as inlays., Materials and Methods: Ten partially edentulous patients, requiring bilateral and vertical bone augmentation of the posterior mandible (having 5 to 7mm of residual crestal height and at least 5mm thickness above the mandibular canal to allow for implant placement) had their posterior mandibles randomly allocated to both interventions. Resorbable barriers were used to cover the grafts. After 4 months, implants were inserted, and after a further 4 months, provisional prostheses were inserted. Definitive prostheses were delivered 4 months later. Prosthesis and implant failures, the amount of vertically regenerated bone measured on computerised tomography (CT) scans, any complications, the time needed to fully recover mental nerve sensitivity and patient preference were all recorded. All patients were followed up for up to 1 month after the delivery of the final restorations., Results: Up to 5 months post-loading no patients dropped out or were excluded. Both procedures obtained significant bone gain and achieved the desired results. Four months after grafting, autogenous bone loss was on average 1.1mm (P=0.088) and Bio-Oss 0.6mm (P=0.001). There were no statistically significant differences in bone gain and maintenance among the two procedures. The sides treated with Bio-Oss recovered their full mental nerve sensitivity significantly faster than those treated with autogenous bone (4 versus 6.3 days). Three complications occurred during graft healing; two in the autogenous bone group and one determining the complete failure of the augmentation procedure. No implants or prosthesis could be placed in the planed area. There was no statistically significant differences in the occurrence of complications between the procedures. After implant placement one complication occurred in the autogenous bone group (probably as a consequence of a previous complication). Patients significantly preferred the treatment with Bio-Oss: 3 weeks after augmentation seven patients preferred Bio-Oss and three patients found the treatments to be 'equally good' (odds ratio 0.045 [5% confidence interval (CI) 0.00 to 0.87], P=0.04). One month after delivery of the final prostheses, eight patients preferred Bio-Oss and two patients found the treatments to be 'equally good' (odds ratio 0.03 [95% CI 0.00 to 0.64], P=0.02)., Conclusions: This pilot study suggests that it might be sensible to use Bio-Oss blocks rather than bone harvested from the iliac crest as the interpositional graft in the treatment of resorbed posterior mandible, as patient discomfort is reduced.