Short (5 and 7 mm long) porous implants in the posterior atrophic maxilla: a 5-year report of a prospective single-cohort study

PURPOSE

The aim of this ongoing prospective study was to determine the 5-year survival rate of short porous dental implants in the posterior atrophic maxilla combined, when necessary, with crestal sinus floor elevation and often adding anorganic bovine bone.

MATERIALS AND METHODS

In 87 partially edentulous patients, 110 short porous implants were placed and followed up for 5 years. The implants used were of two lengths (5 and 7 mm) and two diameters (4.1 and 5 mm) and were chosen according to the available crestal height and width. In 47 sites, osteotome sinus floor elevation was performed (in 8 cases compacting basal bone, in 39 adding a xenograft). The unloaded healing period was 6 months. A total of 63 implants were restored with single crowns and 47 were splinted to the adjacent implants. Outcome measures were prosthesis and implant failures, any complications, and peri-implant marginal bone resorption.

RESULTS

Five years after loading, no patients dropped out. Eleven implants failed: 2 implants at uncovering and 9 after prosthetic loading. Eleven patients (12.6%) lost 1 implant. In 6 patients (6.9%) a prosthesis failure occurred (implants loaded with single crowns). One surgical complication (membrane perforation) occurred but the implant was normally inserted. No complications occurred during the healing period. In 3 patients, severe peri-implantitis occurred post loading and the implants had to be removed. Two abutments became loose and one crown chipped. At the end of the follow-up period the implant survival rate was 90%, and 93.1% with regard to prosthetic reconstruction. The mean peri-implant marginal bone loss was 1.4 mm.

CONCLUSIONS

The use of short porous implants showed an acceptable clinical outcome in the treatment of the posterior maxilla in this interim 5-year report. Longer follow-ups are needed to confirm these results.

Preservation of posterior mandibular extraction site with allogeneic demineralized, freeze-dried bone matrix and calcium sulphate graft binder before eventual implant placement: a case series

OBJECTIVE

This case series reports short- and long-term healing, before and after placement of an implant, in posterior mandibular extraction sites grafted with demineralized, freeze-dried bone matrix (DFDBM) allograft mixed with calcium sulphate graft binder.

METHODS

Three patients who underwent surgical extraction of a posterior mandibular molar experienced partial loss of the buccal bone plate at the extraction site. Alveolar bone reconstruction with a DFDBM allograft mixed with calcium sulphate graft binder was performed immediately. The graft was covered with a biodegradable regenerative membrane. For each of the 3 patients, the implant and healing abutment were placed after 6, 9 and 12 months, respectively, followed by crown placement 3, 5 and 5 months later, respectively. The implants were periodically re-evaluated, both clinically and radiographically, between 10 and 39 months after final insertion of the crown. An implant stability device was used to evaluate the long-term biological and functional stability of the implants.

RESULTS

Upon exposure and implant placement, the grafted alveolar ridge in all patients presented appropriately sized, dense and well-vascularized bone, wide enough to receive the planned wide-platform implant. The long-term interface stability quotient ranged from 87 to 90.

CONCLUSIONS

Posterior mandibular extraction sites with compromised buccal alveolar bone may be effectively managed by immediate alveolar augmentation using a mixture of DFDBM allograft and calcium sulphate graft binder. This approach provides ideal alveolar form and consistency for eventual placement of the implant.

In vivo comparison of two bone substitutes in the distal femur of the rabbit

PURPOSE

This study aimed to microradiographically evaluate the healing of grafted defects using a surgically standardized model that was suitable for comparing the regenerative potential of different grafts.

MATERIALS AND METHODS

Two different biomaterials, bovine porous bone mineral (BPBM) and nanohydroxyapatite (NHA), were used to fill defects produced in the distal epiphyses of 10 adult male rabbits for 2 and 4 months. Three rabbits were left untreated, without defects, as controls. Evaluations were performed on microradiographs of sections of polymethyl methacrylate-embedded rabbit epiphyses. The amounts of graft material and bone were evaluated by splitting the filled hole into three portions.

RESULTS

A greater amount of BPBM granules were in contact with bone at both 2 and 4 months versus the NHA (statistically significant difference in the central portion of the defect), and a persistence of the BPBM over time was apparent. The amount of NHA decreased from the inner to the outer portion of the defect, particularly after 4 months. The bone amount increased from the inner to the outer portion, particularly for the NHA graft, which produced an early cortex. The amount of mineralized material reached about 80% in the BPBM and 40% to 60% in the NHA after 4 months.

CONCLUSION

Both the analyzed biomaterials performed adequately for bone regeneration. The two biomaterials are probably suitable for grafting defects related to early cortical formation or spacemaintaining clinical requirements.

Clinical evaluation of demineralized bone allograft for sinus lifts in humans: a clinical and histologic study

PURPOSE

Severe alveolar bony resorption in the edentulous posterior maxilla and pneumatization of the maxillary sinus wall make traditional implant placement impossible in the posterior maxilla. To reconstruct the severely resorbed maxilla for dental implant placement, 1 successful technique is to elevate the maxillary sinus floor using demineralized bone matrix (DBM) grafts. The purpose of this study was to evaluate a histologic and histomorphometric evaluation of DBM grafts in the human maxilla.

PATIENTS AND METHODS

Nine months after grafting, at the time of dental implantation, biopsy samples were taken from the grafted areas of 8 patients and were analyzed histologically.

RESULTS

All the sinus lifts were successful in the clinical study conducted after implantation. Resorption of the graft materials and new bone formation were observed, and there was direct deposition of bone on the surface of the graft particles.

CONCLUSION

The results of this study indicate that limited maxillary sinus lift with DBM graft material is a clinically reliable preimplant procedure.

Alveolar ridge augmentation: comparison of two socket graft materials in implant cases

With the variety of bone grafting materials available and their use around both natural teeth and dental implants, clinicians need to understand not only basic bone biology but also characteristics of different bone grafting materials to make a proper choice when selecting a material for alveolar bone augmentation and implant treatment. The grafting materials used in the maxillofacial region include autogenous bone, allografts, xenografts, alloplastic or synthetic products, and composite grafts (combination of different materials). This case report describes two frequenly used bone graft materials for socket preservation immediately after extraction: Puros® (Zimmer Dental Inc, www.zimmerdental.com) (allogeneic) and Bio-Oss®(Osteohealth Co, www.osteohealth.comwww.osteohealth.com) (xenogeneic). In the case presented, the authors perform biologic, clinical, radiologic, and histologic analysis of the two grafting materials by placing them side-by-side in the same patient during implant reconstruction. Implant-related phases of bone augmentation are proposed, and an overview of bone grafting materials, specifically Bio-Oss and Puros, is presented.

Maxillary sinus augmentation with bovine bone and simultaneous dental implant placement in conditions of severe alveolar atrophy: a retrospective analysis of a consecutively treated case series

OBJECTIVE

To retrospectively analyze 14 consecutively treated cases of dental implants placed along with sinus lift procedures in patients with severe bone atrophy (residual bone height of 2 to 5 mm).

METHOD AND MATERIALS

Thirty-one implants were placed with a lateral window sinus lift in 14 patients using deproteinized bovine bone alone (no membrane) for the graft. The implants were monitored for a mean 43.20 ± 9.30 months (minimum, 25.00 months; maximum, 53.00 months) after placement and 32.40 ± 11.10 months (minimum, 11.40 months; maximum, 41.60 months) after fitting of the prostheses. The outcome measures evaluated were implant success, radiographic measurements (original alveolar bone height, peri-implant marginal bone loss, and relationship of implant apex to graft), implant-related probing pocket depth (PPD), Bleeding Index (BI), and prosthesis sucess.

RESULTS

The implant success rate was 93.3%. The mean real alveolar bone height was 3.05 ± 0.87 mm, and there was evidence of peri-implant marginal bone loss (mean, 1.02 ± 1.40 mm). The relationship of implant apex to graft remained stable during follow-up. PPD was < 5 mm in 91.6% of implants. The BI was 11.6%. The prosthetic success rate was 100%.

DISCUSSION

These findings indicate that dental implants can be employed successfully, even in conditions of severe bone atrophy, using only heterologous bone, provided suitable methods and materials are used (eg, site preparation, rough implant surfaces, and self-tapping screw implants).

CONCLUSION

The treatment described appears to afford acceptable results, with lower overall costs and treatment time.

Comparison of new bone formation in the maxillary sinus with and without bone grafts: immunochemical rabbit study

PURPOSE

The aim of this animal study was to evaluate, through immunochemical analysis, new bone formation in rabbit maxillary sinuses with and without bone grafts.

MATERIALS AND METHODS

Bilateral sinus augmentation procedures were performed in rabbits. Bony windows were created with a piezoelectric surgical device with a saw insert. In the first group, the bony window was repositioned after careful elevation of the sinus mucosa without bone grafting. A miniscrew was inserted into the bony window to support the elevated sinus membrane. In the second group, anorganic bovine graft (Bio-Oss) was grafted after very careful elevation of the sinus membrane. Collagen membrane was placed over the bone graft. Rabbits were sacrificed after 1, 2, 4, 6, and 8 weeks. The augmented sinuses were evaluated by immunochemical analysis of proliferating cell nuclear antigen (PCNA), type I collagen, and osteocalcin content.

RESULTS

Immunochemically positive cells for PCNA were present along the floor of the replaced bony window and the elevated sinus membrane from 1 to 4 weeks in the graftless group. In the grafted group, immunochemically positive cells for PCNA were not present after 1 week. In the ungrafted group, the expression of type I collagen was present from week 1. However, the expression of type I collagen was present after 2 weeks in the grafted group. Osteocalcin was observed in both groups after 1 week. Osteocalcin was observed along the floor of the replaced bony window in the graftless group but was not observed along the collagen membrane in the grafted group.

CONCLUSION

According to this immunochemical study, faster and greater new bone formation was observed in sites that received no grafting material. The repositioned bony window may accelerate new bone formation earlier during healing versus the placement of a collagen membrane grafting material in the sinus.

Allograft bone matrix versus synthetic bone graft substitutes

Autologous bone is used very often in the treatment of fresh fractures, delayed unions and non-unions. Alternatives have included allografts and in recent years also demineralized bone matrix. The growing availability of good synthetic bone grafts and their advantages in safety and avoiding donor-site morbidity are the reasons that these products are being used more and more. There are on the market a wide variety of substitutes with different capabilities. Nevertheless autologous bone graft is still considered as the gold standard and will be discussed here in that context. Osteoconductive, osteogenic and osteoinductive products will also be classified and their advantages and disadvantages described.

Clinical prospective study of a modified technique to extend the keratinized gingiva around implants in combination with ridge augmentation: one-year results

PURPOSE

The aim of this study was to evaluate the effectiveness of a modified surgical technique to extend the keratinized gingiva around implants in augmented mandibles and the stability of the technique after 1 year.

MATERIALS AND METHODS

Implants were inserted in mandibles in combination with ridge augmentation and extension of deficient buccal keratinized gingiva (BKT) with free gingival grafts (FGGs), in which the keratinized local gingiva (KLG) was transferred toward the lingual. In group 1, implants were placed simultaneous with ridge augmentation, and FGGs were performed at the time of uncovering the implants. In group 2, the implants were placed after ridge augmentation, and FGGs were performed at the time of implant placement with nonsubmerged healing. The width of KLG and FGG, as well as the width of the BKT and lingual keratinized gingiva (LKT), were measured 4 weeks, 3 months, and 1 year after soft tissue grafting.

RESULTS

Seventy implants (46 in group 1, 24 in group 2) were placed in 29 patients with a mean age of 54.4 years. The mean width of KLG was 2.90 mm preoperatively (3.00 mm for group 1, 2.75 mm for group 2). Mean FGG was 4.60 mm in group 1 and 4.70 mm in group 2. For group 1 the mean width of BKT was 3.70 mm after 1 year. In contrast, group 2 showed mean BKT of 3.30 mm after 1 year. The resultant overall gain in BKT was 3.50 mm at 1 year. The LKT exhibited significantly more atrophy in group 1 (0.35 mm at 1 year) than in group 2 (0.05 mm at 1 year).

CONCLUSIONS

The combination of ridge augmentation with the presented modified surgical technique resulted in the stable extension of keratinized gingiva around implants for 1 year.

Bone-added osteotome sinus floor elevation for the deficient maxillary posterior implant site: case series

Implant placement in the posterior maxillary region is often compromised due to anatomic limitations. Often, factors like inadequate vertical dimension, poor bone quality, and undercuts result in placement of shorter and/or angled implants. The bone-added osteotome sinus floor elevation technique can be employed in many clinical situations that involve minimal bone height, resulting in increased bone height and placement of longer implants. This article will briefly review the literature and provide a detailed description of the technique as well as present multiple cases in which this procedure was used.

Ridge enlargement using deproteinized bovine bone and a bioresorbable collagen membrane: a tomodensitometric, histologic, and histomorphometric analysis

The aim of this paper was to study, through a clinical case report, the behavior of deproteinized bovine bone (Bio-Oss) covered with a resorbable barrier membrane (Bio-Gide) when used as an onlay grafting material to obtain alveolar bone ridge enlargement. The presence of an existing bone edge allowed placement of an MK III groovy implant and creation of the required space for ridge enlargement, using xenograft particles (Bio-Oss) covered with a resorbable barrier membrane (Bio-Gide), during the same surgical stage. Recording of anatomical landmarks in the three dimensions of space in relation to implant position allowed precise assessment of the graft behavior during the tomodensitometric examinations performed at 6 and 18 months postsurgery. A biopsy was performed at 9 months postsurgery for histologic and histomorphometric analyses. The tomodensitometric images allowed observation of the preservation of the grafted bone volume. The histologic analysis revealed vital bone formation with the remaining Bio-Oss particles; the histomorphometric analysis, at this stage, provided similar percentages of Bio-Oss (27.94%) and newly formed bone (24.07%). This clinical example confirms the biocompatible and osseoconductive properties of Bio-Oss, as well as stability of the bone graft volume. These different elements testify to the advantage of its use for alveolar ridge enlargement.

Microcomputed tomographic and histologic analysis of anorganic bone matrix coupled with cell-binding peptide suspended in sodium hyaluronate carrier after sinus augmentation: a clinical study

PURPOSE

Anorganic bovine hydroxyapatite matrix (ABM), when coupled with synthetic cell-binding peptide (P15), mimics the cell-binding region of type 1 collagen and is commercially available suspended in a sodium hyaluronate carrier. The aim of the present study, therefore, was to test the efficacy of ABM/P-15 Putty (DENTSPLY Friadent CeraMed) as a sole graft material for sinus augmentation in patients with severely resorbed posterior maxillae.

MATERIALS AND METHODS

Sinus augmentation was performed in 10 patients using ABM/P-15 Putty and two provisional dental implants (3.0 mm in diameter). The graft and implants were placed simultaneously with the aid of a surgical stent. After 8 or 16 weeks, the implants were removed using a 4.25-mm trephine bur; this was followed by immediate placement of wider-diameter (5.5-mm) implants. All 20 implants were scanned by microcomputed tomography to determine bone mineral density (BMD), percent bone volume (PBV), and percent bone contact (PBC).

RESULTS

There was a significant increase in the BMD of bone around the implants at 8 weeks and 16 weeks compared to native residual (control) bone. There was no significant difference in PBV or PBC between 8 weeks and 16 weeks. The average increase in bone height at 16 weeks was 9.63 ± 1 mm. Microcomputed tomographic images and histologic sections showed dense graft particles surrounded by vital trabecular bone.

CONCLUSION

BMD increases as early as 8 weeks and does not show an additional increase after 16 weeks. PepGen P-15 Putty was found to be a promising osteoconductive graft for sinus augmentation, supporting immediate placement of implants.

Delayed implant procedure using deproteinized bovine bone mineral: A report of 109 consecutive cases

PURPOSE

The purpose of this consecutive case series was to analyze the success rate of endosseous implants placed into deproteinized bovine bone mineral (DBBM) maxillary and mandibular grafted extraction sites during a 48-month period.

METHODS

During a 48-month period, 69 consecutive patients presented with 109 nonrestorable teeth. The teeth were extracted and the sites grafted with DBBM, and the extraction sockets were allowed to heal for an average of 6 months. Following healing, implants were placed in the grafted sites. Osseointegration was assessed based on a lack of mobility and a radiographic evaluation.

RESULTS

Implants were placed in all of the 109 grafted sites with no graft failures. No implant was mobile at uncovering. All 109 implants are currently loaded and have been in function for 6 months to 65 months with an average of 2 years for a 100% cumulative success rate. Marginal soft-tissue levels remain stable.

CONCLUSION

The delayed implant approach using DBBM is a predictable treatment modality, resulting in long-term implant stability and predictable esthetic results.

Stem cell-containing allograft matrix enhances periodontal regeneration: case presentations

Periodontal defects involving either interproximal horizontal bone loss or furcations continue to challenge the regenerative capabilities of the oral cavity. The following case presentations show the successful treatment of these challenging periodontal defects with a novel cellular allograft that contains native mesenchymal stem cells and osteoprogenitor cells.

Peri-implant tissue response following connective tissue and bone grafting in conjunction with immediate single-tooth replacement in the esthetic zone: a case series

PURPOSE

This case series evaluated the peri-implant tissue response following extraction and immediate placement and restoration of an implant in conjunction with subepithelial connective tissue grafting (SCTG) and bone grafting in the esthetic zone. Implant success rates and the peri-implant tissue response were also reported.

METHODS AND MATERIALS

Ten patients (four men, six women) with a mean age of 48 years (range, 35 to 70) underwent extraction and immediate tooth replacement with SCTG and were evaluated clinically and radiographically presurgically (T0), immediately after immediate tooth replacement and SCTG (T1), and at 3 months (T2), 6 months (T3), and 12 months (T4) after surgery. Data was analyzed using Friedman and Wilcoxon signed-ranks tests at the significance level of a = .05.

RESULTS

At 1 year, all implants remained osseointegrated, with an overall mean marginal bone change of +0.10 mm and a mean facial gingival level change of -0.05 mm. Modified Plaque Index scores showed that patients were able to maintain a good level of hygiene throughout the study. Papilla Index scores indicated that at T4, more than 50% papilla fill was observed in 80% of all sites.

CONCLUSIONS

The results of this case series suggest that, in addition to a favorable implant success rate and peri-implant tissue response, the facial gingival level around single immediately placed implants can also be maintained following connective tissue grafting when proper three-dimensional implant positioning is achieved and bone is grafted into the implant-socket gap.

Healing of ungrafted and grafted extraction sockets after 12 weeks: a prospective clinical study

PURPOSE

In this prospective study, bone formation in human extraction sockets augmented with Bio-Oss Collagen after a 12-week healing period was quantified and compared to bone formation in unaugmented extraction sockets.

MATERIALS AND METHODS

Selected patients with four-walled extraction sockets were included in this prospective study. After extraction, the sockets were randomly augmented using Bio-Oss Collagen or left to heal unfilled without raising a mucoperiosteal flap. At the time of implant placement, histologic specimens were obtained from the socket and analyzed. Statistical analysis was performed using the Wilcoxon signed-rank test.

RESULTS

Twenty-five patients with a total of 39 sockets (20 augmented, 19 unaugmented) were included in the study and the histologic specimens analyzed. All specimens were free of inflammatory cells. The mean overall new bone formation in the augmented sites was 25% (range, 8%-41%) and in the unaugmented sockets it was 44% (range, 3%-79%). There was a significant difference in the rate of new bone formation between the grafted and ungrafted sockets and a significant difference in the bone formation rate in the apical compared to the coronal regions of all sockets, independent of the healing mode.

CONCLUSION

This descriptive study demonstrated that bone formation in Bio-Oss Collagen-grafted human extraction sockets was lower than bone formation in ungrafted sockets. Bone formation occurred in all specimens with varying degrees of maturation independent of the grafting material and was initiated from the apical region.

Applicability of equine hydroxyapatite collagen (eHAC) bone blocks for lateral augmentation of the alveolar crest. A histological and histomorphometric analysis in rats

This study assessed the mechanical characteristics, biocompatibility and osteoconductive properties of an equine hydroxyapatite collagen (eHAC) bone block when applied as a bone substitute for lateral augmentation of rat mandible. 96 rats underwent lateral augmentation of the mandible, using two substitute bone blocks (eHAC or Bio-Oss spongiosa) or autologous bone grafts. Signs of inflammation, amount of bone formation and ingrowth of bone into the bone blocks were assessed at 1 and 3 months. eHAC blocks were mechanically rigid and could be fixed firmly and easily. Bio-Oss spongiosa blocks were brittle and fixation was difficult. eHAC and Bio-Oss spongiosa blocks were biocompatible and induced few or no signs of inflammation. Inflammation prevalence between the groups was not statistically different. Bone formation and bone growth into the blocks was significantly higher in eHAC than Bio-Oss spongiosa blocks, but lower than in autologous bone grafts (after 1 and 3 months). Regression analysis showed that the autologous bone graft predicted new bone formation at both time points. The eHAC block was only a predictor at 1 month; a trend was found at 3 months. The application of biodegradable membranes was not related to more bone ingrowth.

Evaluation of osteoinduction properties of the demineralized bovine foetal growth plate powder as a new xenogenic biomaterial in rat

The aim of this study was evaluation of osteoinductive properties of demineralized bovine foetal growth plate in submuscular transplantation (ectopic osteoinduction) as a new xenogenic biomaterial in rat model. Demineralized bovine foetal growth plate was ectopically implanted in 18 male Sprague-Dawley rats. In 18 of the animals under aseptic conditions two submuscular pouches were created between external and internal oblique abdominal muscles in the two flanks: the right was left empty (sham) and the left was filled with 20mg of demineralized bovine foetal growth plate powder. Radiographs were taken in 2, 4 and 6 weeks after the surgery, then six animals were pharmacologically euthanized after 2, 4 and 6 weeks for histopathological evaluation. Results showed: (1) osteoinductivity of xenogenic demineralized bovine foetal growth plate powder, and (2) earlier mineralization of ectopically implanted demineralized bovine foetal growth plate in the submuscular implanted area. Our results show that submuscular implantation of xenogenic demineralized bovine foetal growth plate has osteoinductive properties in a rat model.

Immediate non-occlusal loading of immediate post-extractive versus delayed placement of single implants in preserved sockets of the anterior maxilla: 4-month post-loading results from a pragmatic multicentre randomised controlled trial

PURPOSE

To compare the effectiveness of immediate post-extractive single implants with delayed implants placed in preserved sockets after 4 months of healing. Implants that achieved an insertion torque of at least 35 Ncm were immediately non-occlusally loaded.

MATERIALS AND METHODS

Just after tooth extraction and in the presence of a loss of the buccal plate bone less than 4 mm, compared to the palatal wall, 106 patients requiring a single immediate postextractive implant in the maxilla from second premolar to second premolar were randomly allocated to immediate implant placement (immediate group; 54 patients) or to socket preservation using anorganic bovine bone covered by a resorbable collagen barrier (delayed group; 52 patients) according to a parallel group design at three different centres. Bone-to-implant gaps were to be filled with anorganic bovine bone, however this was not done in 17 patients (corresponding to 40% of those who should have been grafted). Four months after socket preservation, delayed implants were placed. Implants placed with an insertion torque >35 Ncm were immediately loaded with non-occluding provisional single crowns, replaced, after 4 months, by definitive crowns. Outcome measures were implant failures, complications, aesthetics assessed using the pink esthetic score (PES), and patient satisfaction, recorded by blinded assessors. All patients were followed up to 4 months after loading.

RESULTS

Nineteen (35%) implants were not immediately loaded in the immediate group versus 39 (75%) implants in the delayed placement group because an insertion torque >35 Ncm could not be obtained. No patient dropped out. Two implants failed in the immediate group (4%) versus none in the delayed group. More minor complications occurred in the immediate group (8) than the in the delayed group (1) and this was statistically significant (P = 0.032). At delivery of definitive crowns, 4 months after loading, aesthetics were scored as 12.8 and 12.6 in the immediate and delayed groups, respectively. There was no statistically significant difference (P = 0.5). Patients of both groups were equally satisfied.

CONCLUSIONS

There were more complications at immediate post-extractive implants when compared to delayed implants. The aesthetic outcome appears to be similar for both groups and it seems more difficult to obtain a high insertion torque in sockets preserved with anorganic bovine bone.

A 3-year post-loading report of a randomised controlled trial on the rehabilitation of posterior atrophic mandibles: short implants or longer implants in vertically augmented bone?

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.

Histologic and histomorphometric evaluation of an allograft stem cell-based matrix sinus augmentation procedure

PURPOSE

Long-term success of dental implants has been demonstrated when placed simultaneously with or after a sinus augmentation procedure. However, optimal bone formation can be from 6 to 9 months or longer with grafting materials other than autogenous bone. For this reason, there is interest in any surgical technique that does not require autogenous bone harvesting, yet results in sufficient bone formation within a relatively short time frame.

MATERIALS AND METHODS

This study evaluated and compared bone formation following sinus-augmentation procedures using either an allograft cellular bone matrix (ACBM), containing native mesenchymal stem cells and osteoprogenitors, or conventional allograft (CA).

RESULTS

Histomorphometric analysis of the ACBM grafts revealed average vital bone content of 32.5% ± 6.8% to residual graft content of 4.9% ± 2.4% for the 21 sinuses in the study, at an average healing period of 3.7 ± 0.6 months. Results for the CA, in the same time frame, were average vital bone content of 18.3% ± 10.6% to residual graft content of 25.8% ± 13.4%. A comparison of ACBM and CA grafts, for both vital and residual bone contents, showed P values of .003 and .002, respectively, indicating a statistically significant difference between the groups.

CONCLUSION

The high percentage of vital bone content, after a relatively short healing phase, may encourage a more rapid initiation of implant placement or restoration when a cellular grafting approach is considered.

Reconstruction of an atrophied posterior mandible with the inlay technique and inorganic bovine bone block: a case report

A 53-year-old woman underwent bilateral reconstruction of her severely atrophic posterior mandible using inlay inorganic bovine bone block grafting. Four months later, a bone specimen was taken for histologic evaluation and eight dental implants were placed. These implants were loaded with a provisional prosthesis after another 4 months. When the definitive prosthesis was inserted 8 months postsurgery, all implants were osseointegrated. Histologic analysis showed that the grafted bone was lined with newly formed bone. The results indicate that inorganic bovine bone blocks might serve as an alternative to autogenous grafting for posterior mandibular augmentation using the inlay technique.