The edentulism of the jaws and the periodontal disease represent conditions that frequently leads to disruption of the alveolar bone. The loss of the tooth and of its bone of support lead to the creation of crestal defects or situation of maxillary atrophy. The restoration of a functional condition involves the use of endosseous implants who require adequate bone volume, to deal with the masticatory load. In such situations the bone need to be regenerated, taking advantage of the biological principles of osteogenesis, osteoinduction and osteoconduction. Several techniques combine these principles with different results, due to the condition of the bone base on which we operate changes, the surgical technique that we use, and finally for the bone metabolic conditions of the patient who can be in a state of systemic osteopenia or osteoporosis; these can also affect the result of jaw bone reconstruction.

The immunohistochemical characteristics of wound healing following application of a biphasic calcium phosphate or a collagen coated natural bone combined with a native collagen membrane in a dog model was assessed. Standardized buccal dehiscence-type defects were surgically created following implant bed preparation in 6 dogs. Following implant placement, defects were randomly filled with a collagen coated natural bone mineral (GBO), or a biphasic hydroxyapatite/beta tricalcium phosphate (SBC), and covered with a native collagen membrane. After 1, 4, and 9 weeks' submerged healing, dissected blocks were processed for immunohistochemical (collagen type I (CI), osteocalcin (OC), angiogenesis (TG)) analysis. At 1 week, GBO and SBC granules were homogeneously surrounded by a well vascularized, non-mineralized tissue (NMT). CI and OC antigen reactivity was commonly observed adjacent to both bone graft substitutes. At 4 and 9 weeks, SBC and GBO granules were completely integrated into a secondly formed network of spongiosa. At 9 weeks, dissolution of some granules was observed in the SBC group. Adjacent to these granules, NMT was significantly increased and revealed a pronounced CI, OC and TG antigen reactivity. The initial pattern of bone regeneration and graft integration was comparable in both groups; bone remodelling was more pronounced with SBC.

OBJECTIVES To evaluate by histology the effect of loading on the regenerated bone at dehiscence type defects around implants when treated with a combined approach of bone grafting and guided bone regeneration (GBR). MATERIALS AND METHODS In twelve Göttingen mini-pigs, the lower premolars and first molars were extracted and the alveolar process was reduced in width. After 3 months, two Straumann SLActive® (Straumann AG, Basel, Switzerland) implants were placed in each hemi-mandible. Twelve implants were placed into the reduced alveolar ridge (group P) with no further defect or treatment on the site, while on 36 implants, buccal dehiscence defects were created and treated as follows: Group T1: synthetic bone substitute (Straumann Bone Ceramic(®), SBC, Straumann AG). Group T2: SBC with a polyethylene glycol membrane (Straumann MembraGel(®), Straumann AG); Group N: the dehiscence remained untreated. Three months following implantation, long, custom-made, healing abutments were placed in one hemi-mandible only to ensure functional loading. After 2 months, histological analysis was performed. RESULTS A trend for lower residual defect height and higher bone-to-implant contact was observed in the loaded sites compared with non-loaded sites in groups P, T1 and N. In group T2, the opposite effect was observed. In terms of bone formation, sites treated with SBC grafting and GBR (group T2) exhibited the largest surface area of regenerated bone followed by T1 and N. Significant resorption of the graft particles was noted in group T2 and the graft surface area occupied by SBC was significantly higher in group T1 compared with group T2 (P < 0.05). CONCLUSIONS Loading may have a positive effect on bone-to-implant contact in implants inserted in pristine bone or inserted in dehiscence sites and treated by grafting/no grafting.

OBJECTIVE: The purpose of this study was to compare the effects of two different resorbable collagen membranes on new bone formation after sinus grafts with anorganic bovine bone mineral (BBM). MATERIALS AND METHODS: For 64 patients presenting with an initial residual bone height ≤4 mm at the posterior maxilla, the sinus floors were grafted with BBM (Bio-Oss(®)). The lateral windows were covered by one of the two bio-resorbable membranes, Bio-Arm(®) or Bio-Gide(®). The histomorphometric data were obtained 7-15 months after sinus augmentation at the time of the implant installation. RESULTS: The core biopsy specimens of Bio-Arm (n = 37 sites) and Bio-Gide group (n = 22 sites) were compared. The results showed that the BBM particles were in direct contact with the newly formed bone in all cases. In histomorphometric analysis, the Bio-Gide group showed significantly higher new bone formation (33.3 ± 12%) compared with the Bio-Arm group (26.3 ± 8.1%)(P < 0.05). All the implants survived successfully after a mean follow-up of 35.3 months (range 22-63 months) in the Bio-Arm group and 55.5 months (range 35-66 months) in the Bio-Gide group. The amount of new bone in the specimens did not significantly correlate with the residual bone height at the time of surgery or the length of the healing period. CONCLUSIONS: The type of resorbable membrane did not readily affect the long-term survival of the implants at the grafted sinus. On the other hand, Bio-Gide group showed more new bone formation than the Bio-Arm group, which implied that the function of the membrane can influence the remodeling of the grafted sinus. As the amount of residual bone substitute particle had not decreased significantly over time, the results suggest that the BBM was rarely resorbable for at least 15 months after the surgery.

PURPOSE The purpose of this study was to evaluate the effectiveness of autogenous tooth bone graft materials. MATERIALS AND METHODS Hundred implants in 51 patients were selected, and the patients received maxillary sinus augmentation and implant placement using autogenous tooth graft materials at the Chosun University Dental Hospital and Seoul National University Bundang Hospital between July 2009 and November 2010. RESULTS In cases using autogenous tooth bone graft alone, or together with other graft material, the implant survival rate was 96.15%. On histomorphologic examination, autogenous tooth bone graft materials showed gradual resorption and new bone formation through osteoconduction and osteoinduction. CONCLUSIONS The results indicated that autogenous tooth bone graft materials are appropriate for use in maxillary sinus augmentation.

Membranes made of several different materials are available in the market, nonresorbable (e.g. ePTFE), resorbable (e.g. synthetic or collagen) and liguid applicable (e.g. Polyethylene glycol or Atrisorb). The purpose of the present study was to evaluate whether or not in situ application of Atrisorb could be used as a barrier membrane for guided bone regeneration. Ten patients with insufficient alveolar ridge width for implant placement participated in the study. Atrisorb in conjunction with various bone grafts was used to treat 10 different sites, 3 sites treated prior to implant placement and 7 sites in conjunction with implant placement. Augmented sites were allowed to heal for 3 to 7 months, with mean healing time of 4.7 months. Healing was uneventful with no major complications. Two sites experienced a flap dehiscence accompanied by barrier exposure during the initial healing period. Secondary healing was achieved soon after with no signs of infection, giving Atrisorb a barrier exposure rate of 20% for the present study, which corresponds to favorably to that of resorbable membranes. The liquid membrane has the potential of being a viable alternative to traditional resorbable membranes for use in GBR procedures.

The purposes of this prospective, randomized, controlled clinical investigation were to evaluate the performance of motorized ridge expanders (MREs) and to compare their results with those achieved using lateral ridge augmentation (LRA). Eight subjects with bilateral ridge deformities were selected. One technique was used on the right side and the other on the left. Implants were placed 6 months after bone augmentation procedures. All measurements were recorded at 2 and 5 mm from the most coronal aspect of the crest. The augmentation achieved with both techniques was statistically significant: 1.2 mm for LRA and 1.5 mm for MRE 2 mm from the crest and 1.5 mm for LRA and 1.6 mm for MRE at 5 mm from the crest. The differences between the two techniques were statistically insignificant. The amount of expansion achieved in the MRE sites appeared to be negatively correlated with the thickness of the cancellous bone (P <.05), and it was not affected by the thickness of the cortical plate. The MRE technique appears to be as effective as the LRA technique in augmenting the thickness of atrophic ridges. Defects treated with MREs showed less bone width contraction during the first 6 months of healing.(Int J Periodontics Restorative Dent 2011;31:547-554.).

OBJECTIVE: The physicochemical properties of hydroxyapatite (HA) granules were observed to affect the biological behavior of graft materials. The aim of this work was to analyze the tissue response of two HA granules with different crystallinity and Ca/P ratio in vivo. MATERIAL AND METHODS: The HA granules were produced in the Biomaterials Laboratory (COPPE/UFRJ). The testing materials were HA granules presenting a Ca/P molar ratio of 1.60 and 28% crystallinity (HA-1), and a Ca/P molar ratio of 1.67 and 70% crystallinity (HA-2). Both HAs were implanted into a critical-size calvaria rat defects. RESULTS: To note, in the control group, the bone defects were filled with blood clot only. Descriptive and histomorphometric analyses after 1, 3, and 6 months postoperatively showed mild inflammatory infiltrate, mainly comprising macrophage-like and multinucleated giant cells, and an increase in the volume density of the fibrous tissues (p<0.05), which was in contrast to the similar volume density of the newly formed bone and biomaterials in relation to the control group. CONCLUSION: Thus, we concluded that HA-1 and HA-2 are biocompatible and non-degradable, and that crystallinity does not affect bone repair of critical size defects.

Objectives:(i) To evaluate biodegradation, hard and soft tissue integration using various polyethylene glycol (PEG) hydrogels;(ii) to evaluate the influence of arginine-glycine-aspartic acid (RGD) on two types of PEG hydrogels. Material and methods: In seven rabbits, six treatment modalities were randomly applied subperiosteally on the skull:(1) a dense network PEG hydrogel (PEG1),(2) PEG1 modified with RGD (PEG1-RGD),(3) a looser network PEG hydrogel (PEG2),(4) PEG2 modified with RGD (PEG2-RGD),(5) a collagen membrane, and (6) a polylactide/polyglycolide/trimethylene carbonate membrane. The animals were sacrificed at 14 days. Histomorphometric analyses were performed on undecalcified Epon sections using a standardized region of interest. For statistical analysis, paired t-test and signed rank test were applied. Results: PEG1 and PEG1-RGD remained intact and maintained the shape. PEG2 and PEG2-RGD completely degraded and were replaced by connective tissue and bone. The largest amount of mineralized tissue was found for PEG2-RGD (21.4%), followed by PEG 2 (9.5%). The highest percentage of residual hydrogel/membrane was observed for PEG1-RGD (55.6%), followed by PEG1 (26.7%). Conclusions: Modifications of the physico-chemical properties of PEG hydrogels and the addition of RGD influenced soft and hard tissue integration and biodegradation. PEG1 showed an increased degradation time and maintained the shape. The soft tissue integration was enhanced by adding an RGD sequence. A high turn-over rate and extensive bone regeneration was observed using PEG2. The addition of RGD further improved bone formation and soft tissue integration. To cite this article: Thoma DS, Subramani K, Weber FE, Luder HU, Hämmerle CHF, Jung RE. Biodegradation, soft and hard tissue integration of various polyethylene glycol hydrogels: a histomorphometric study in rabbits. Clin. Oral Impl. Res. xx, 2011; 000-000. doi: 10.1111/j.1600-0501.2010.02075.x.

Objectives: This study was designed to evaluate the effect of bone graft materials and collagen membranes in ridge splitting procedures with immediate implant placement using a dog model. Materials and methods: Mandibular premolars were extracted in five beagle dogs. After 3 months, ridge splitting and placement of three OsseoSpeed(™) implants were performed bilaterally. The gaps between the implants were allocated according to the following eight treatment modalities; Group 1(no graft), Group 2 (autogenous bone), Group 3 (Bio-Oss(®) Collagen), Group 4 (Bio-Oss(®)), Group 5 (no graft+BioGide(®)), Group 6 (autogenous bone+BioGide(®)), Group 7 (Bio-Oss(®) Collagen+BioGide(®)), and Group 8 (Bio-Oss(®)+BioGide(®)). The dogs were sacrificed after 8 or 12 weeks and the specimens were analyzed histologically and histometrically. Results: The gaps between the implants were filled with the newly formed bone, irrespective of which of the eight grafting techniques was used. Group 1 revealed a significantly lower percentage of bone-to-implant contact (BIC) than Group 5 at 8 and 12 weeks (P<0.05). Group 1 showed the most prominent marginal bone loss (MBL) at 12 weeks (P<0.05). Regarding the use of membranes, Groups 1 and 2 showed significantly more MBL than Groups 5 and 6 at 12 weeks (P<0.05). Conclusions: After ridge splitting, if the gaps between implants were grafted or covered with collagen membranes, a higher percentage of BIC was obtained. Based on our results, we suggest that the use of bone graft materials and/or collagen membranes is better for the prevention of MBL after ridge splitting procedures. To cite this article: Han J-Y, Shin S-I, Herr Y, Kwon Y-H, Chung J-H. The effects of bone grafting material and a collagen membrane in the ridge splitting technique: an experimental study in dogs. Clin. Oral Impl. Res. xx, 2011; 000-000 doi: 10.1111/j.1600-0501.2010.02127.x.

The aim of the present study was to investigate the healing of alveolar ridge defects augmented with cancellous bovine bone mineral. In six partially edentulous patients, bone augmentation was necessary prior to implant placement because of severe alveolar ridge resorption. The defect sites, all located in the maxilla, were filled with Bio-Oss and covered with the resorbable collagen membrane Bio-Gide. Biopsies were obtained from the defect sites 6 to 7 months following grafting and were processed for ground sectioning. The histologic analysis revealed that the Bio-Oss particles occupied 31% of the total biopsy area. An intimate contact between woven bone and Bio-Oss was detected along 37% of the particle surfaces. A mixed type of bone was found; it contained woven bone and parallel-fibered bone, which demonstrates features of remodeling activity. Signs of resorption of the grafting material were observed in the histologic sections, which indicates that the material takes part in the remodeling process. It is suggested that Bio-Oss may be a very suitable material for staged localized ridge augmentation in humans.

The aim of this prospective 5-year longitudinal study was to follow endosteal implants in which guided bone regeneration (GBR) was applied during implant placement. In 75 patients, defects around implants (Branemark System) were treated with Bio-Oss and Bio-Gide (112 implants). In split-mouth patients in this group, Bio-Oss and Gore-Tex were used in the second defect site (41 implants). All 75 patients had at least 1 implant that was entirely surrounded by bone and served as the control (112 implants). After placement of the definitive prostheses (single-tooth, fixed, or removable implant prostheses), patients were recalled after 6 months and then every 12 months during a 5-year observation period. The following variables were investigated: implant survival, marginal bone level (MBL), presence of plaque, peri-implant mucosal conditions, height of keratinized mucosa (KM), and marginal soft tissue level (MSTL). The cumulative implant survival rate after 5 years varied between 93% and 97% for implants treated with or without GBR. The mean MBL after 60 months was 1.83 mm for sites treated with Bio-Oss and Bio-Gide, 2.21 mm for sites treated with Bio-Oss and Gore-Tex, and 1.73 mm for the control sites. The MBL values were found to increase significantly with time and differed significantly among the treatment groups. During the observation period, KM varied between 3.16 and 3.02 mm. A slight recession of 0.1 mm was observed, and plaque was found in 15% of all sites and was associated with inflammatory symptoms of the peri-implant mucosa. It was observed that such symptoms and recession correlated more strongly with the type of restoration than with the type of treatment. This study demonstrated that implants placed with or without GBR techniques had similar survival rates after 5 years, but that bone resorption was more pronounced in sites with GBR treatment. It was assumed that the use of GBR is indeed indicated when the initial defect size is larger than 2 mm in the vertical dimension.

The aim of this retrospective clinical study was to evaluate the influence of different factors on the outcome of GBR treatment. 75 patients, who were not randomly assigned to the investigated parameters for clinical reasons, were included in the study. They presented with defect sites around implants and were treated with a xenogenic grafting material and a resorbable collagen membrane. The defect morphology was described, its dimension was measured and calculated at the time of implant installation and at re-entry. The success of GBR treatment was related to several clinical variables and possible correlations were evaluated. Defect sites around maxillary implants showed significantly more bone fill (96%) compared to those in the mandible (78%). The insertion of a provisional restoration during the healing period was also associated with significantly better results than when no provisional was inserted. Immediate and short-term delayed implant placements showed the best results both with 92% bone fill, when compared with long-term delayed placements with 80% bone fill (n.s.). In sites with type I bone quality (compact bone), a reduced bone fill was observed (64%). The results indicate that successful bone fill can be achieved with GBR; this is more feasible in the maxilla, when a provisional restoration is used. Early implant placement timings seem to be preferable due to the alveolar ridge preservation, more favorable defect morphologies and a higher regenerative capacity.

Root-filled teeth with fractured or discolored coronal aspects invariably need to be restored by crowns. The prepared abutment tooth is usually reinforced by a metallic post and core system. The grayish discoloration of the root, and consequently of the gingiva, caused by the metal color may be an enormous esthetic disadvantage in the anterior teeth. In 1993 ceramic posts made of zirconia were introduced by the authors, allowing a new all-ceramic concept for nonvital abutment teeth. A new ceramic post and core system has now been developed with the idea of further improving esthetic appearance. In this system the core material is heat pressed directly onto the zirconia post. This article describes the material and the fabrication procedures (chairside and in the laboratory) of the system. Clinical results are presented. The retention of the core material is evaluated by in vitro tests.

Esthetically correct treatment of a localized alveolar ridge defect is a frequent prosthetic challenge. Such defects can be overcome not only by a variety of prosthetic means, but also by several periodontal surgical techniques, notably soft tissue augmentations. Preoperative classification of the localized alveolar ridge defect can be greatly useful in evaluating the prognosis and technical difficulties involved. A semiquantitative classification, dependent on the severity of vertical and horizontal dimensional loss, is proposed to supplement the recognized qualitative classification of a ridge defect. Various methods of soft tissue augmentation are evaluated, based on initial volumetric measurements. The roll flap technique is proposed when the problem is related to ridge quality (single-tooth defect with little horizontal and vertical loss). Larger defects in which a volumetric problem must be solved are corrected through the subepithelial connective tissue technique. Additional mucogingival problems (eg, insufficient gingival width, high frenum, gingival scarring, or tattoo) should not be corrected simultaneously with augmentation procedures. In these cases, the onlay transplant technique is favored.

OBJECTIVES: The purpose of this study was to compare three different methods for sinus elevation:(1) the lateral antrostomy as a two-step procedure,(2) the lateral antrostomy as a one-step procedure, and (3) the osteotome technique with a crestal approach. Indication criteria were defined, based on the residual bone height measured from computed tomography scans, for the sake of applying the appropriate technique. STUDY: In 30 patients designated for implant treatment in the resorbed posterior maxilla, 79 implants were placed in combination with a bone-grafting material for sinus augmentation. The final bone heights were measured from panoramic radiographs or post-operative computed tomography scans. RESULTS: The success rate for the osteotome technique was 95% during the 30-month study period; no failures occurred in any site treated with a lateral antrostomy. The gain in bone height was comparable for the one-step (median = 10 mm) and two-step (median = 12.7 mm) lateral antrostomies. These sites exhibited a significantly greater increase in bone height (p < 0.001) than did the sites in which the osteotome technique was applied (mean = 3.5 mm). The histologic sections showed both bone apposition in intimate contact with the bone-grafting material particles and initial signs of its remodeling. CONCLUSIONS: The results indicate that the osteotome technique can be recommended when more than 6 mm of residual bone height is present and an increase of about 3 to 4 mm is expected. In cases of more advanced resorption a one-step or two-step lateral antrostomy has to be performed.

Hyposalivation is a common adverse effect of anti-neoplastic therapy of head and neck cancer, causing impaired quality of life and predisposition to oral infections. However, data on the effects of hematopoietic stem cell transplantation (HSCT) on salivary secretion are scarce. The present study determined stimulated whole-saliva flow rates in HSCT recipients in comparison with a healthy control group. Stimulated whole-saliva flow rates of 228 allogeneic HSCT recipients (134 males, 94 females; mean age, 43 yrs) were examined pre-HSCT and 6, 12, and 24 months post-HSCT. Healthy individuals (n = 144; 69 males, 75 females; mean age, 46 yrs) served as the control group. Stimulated saliva flow rates (mL/min) were measured and analyzed statistically, stratifying for hematological diagnoses and conditioning therapy. Hyposalivation (≤ 0.7 mL/min) was found in 40%(p < 0.00001), 53%(p < 0.00001), 31%(p < 0.01), and 26%(n.s.) of the recipients pre-HSCT, and 6, 12, and 24 months post-HSCT, respectively, whereas 16% of the control individuals had hyposalivation. Severe hyposalivation (≤ 0.3 mL/min) was found in 11%, 18%, 4%, and 4% of the recipients pre-HSCT, and 6, 12, and 24 months post-HSCT, respectively. Additionally, conditioning regimen and sex had an impact on saliva flow. In conclusion, hyposalivation was observed to be a common but generally reversible complication among HSCT recipients.

This review describes practical criteria and a systematic process to aid the treatment planning decision of whether to preserve teeth by root canal treatment (RCT) or extract and provide an implant. Recommendations presented are based on best available evidence from the literature and the expert views of specialists in endodontics and restorative dentistry, including dental implantology. A MEDLINE search was conducted using the terms 'root canal therapy','dental implants','decision making','treatment planning','outcome' and 'human', and supplemented by hand-searching. When evaluating the outcome of root canal treatment, an observation period of 4-5 years is required for complete healing of periapical lesions. Dental implants, however, present a de novo situation and a functional period of at least 5 years is often required before peri-implant diseases are established and detected. Good long-term success rates and greater flexibility in clinical management indicate that RCT or retreatment should be performed first in most instances unless the tooth is judged to be unrestorable. When deciding if a compromised tooth of questionable prognosis should be maintained or replaced by an implant, both local, site-specific and more general patient-related factors should be considered. Following systematic evaluation and consideration of the best treatment option in a particular case, a treatment recommendation may then be given in favour or against tooth retention. Whilst single risks are possibly accepted for single tooth restorations, teeth with questionable prognosis and multiple pre-treatment requirements are better not included as abutments in fixed dental prostheses to reduce the risk to survival of the entire restoration.

Donati M, Liljenberg B, Zitzmann NU, Berglundh T. B-1a cells and plasma cells in periodontitis lesions. J Periodont Res 2009; doi: 10.1111/j.1600-0765.2008.01178.x.(c) 2009 The Authors. Journal compilation (c) 2009 Blackwell MunksgaardBackground and Objective: Host response mechanisms in periodontal tissues are complex and involve numerous systems of interactions between cells. The B-cell lineage seems to predominate in chronic periodontitis lesions. The aim of the present investigation was to study the correlation between inflammatory cells and some functional markers in gingival lesions obtained from subjects with severe chronic periodontitis. Material and Methods: Thirty-eight Caucasian subjects volunteered to take part in the study. A gingival biopsy from one randomly selected diseased proximal site (probing pocket depth > 6 mm and bleeding on probing positive) was obtained from each patient. Immunohistochemical preparation was used to identify inflammatory cells and functional markers. Correlations between the different percentages of cell markers were analyzed by pairwise correlation. Results: B cells (B-1a and B-2 cells) occurred in larger proportions than T cells and plasma cells. A statistically significant correlation was found between the percentage of B-1a cells and plasma cells and between all B lymphocytes and plasma cells. About 60% of B lymphocytes exhibited autoreactive features. Conclusion: It is suggested that B-1a cells constitute a significant part of the host response in periodontitis lesions and that plasma cells may develop from both B-2 and B-1a cells.

AIM: To investigate (i) the impact of post fit (form-congruence) and (ii) the influence of post length on the fracture resistance of severely damaged root filled extracted teeth. METHODOLOGY: Ninety-six single-rooted human teeth were root filled and divided into four groups (n = 24 per group). Post spaces were prepared with a depth of 6 mm (group 1, 3) and 3 mm (group 2, 4). Form-congruence with a maximal fit of the post within the root canal space was obtained in groups 1 and 2, whereas there was no form-congruence in groups 3 and 4. In all groups, glass fibre reinforced composite (FRC) posts were adhesively cemented and direct composite crown build-ups were fabricated without a ferrule. After thermo-mechanical loading (1200000x, 5-50 degrees C), static load was applied until failure. Loads-to-failure [in N] were compared amongst the groups. RESULTS: Post fit did not have a significant influence on fracture resistance, irrespective of the post length. Both groups with post insertion depths of 6 mm resulted in significantly higher mean failure loads (group 1, 394 N; group 3, 408 N) than the groups with post space preparation of 3 mm (group 2, 275 N; group 4, 237 N). CONCLUSIONS: Within the limitations of this study, the fracture resistance of teeth restored with FRC posts and direct resin composite crowns without ferrules was not influenced by post fit within the root canal. These results imply that excessive post space preparation aimed at producing an optimal circumferential post fit is not required to improve fracture resistance of roots.

Membranes made of several different materials are available in the market, nonresorbable (e.g. ePTFE), resorbable (e.g. synthetic or collagen) and liguid applicable (e.g. Polyethylene glycol or Atrisorb). The purpose of the present study was to evaluate whether or not in situ application of Atrisorb could be used as a barrier membrane for guided bone regeneration. Ten patients with insufficient alveolar ridge width for implant placement participated in the study. Atrisorb in conjunction with various bone grafts was used to treat 10 different sites, 3 sites treated prior to implant placement and 7 sites in conjunction with implant placement. Augmented sites were allowed to heal for 3 to 7 months, with mean healing time of 4.7 months. Healing was uneventful with no major complications. Two sites experienced a flap dehiscence accompanied by barrier exposure during the initial healing period. Secondary healing was achieved soon after with no signs of infection, giving Atrisorb a barrier exposure rate of 20% for the present study, which corresponds to favorably to that of resorbable membranes. The liquid membrane has the potential of being a viable alternative to traditional resorbable membranes for use in GBR procedures.

OBJECTIVES To evaluate the space-maintaining capacity of titanium mesh covered by a collagen membrane after soft tissue expansion on the lateral border of the mandible in rabbits, and to assess bone quantity and quality using autogenous particulate bone or bone-substitute (Bio-Oss(®)), and if soft tissue ingrowth can be avoided by covering the mesh with a collagen membrane. MATERIAL AND METHODS In 11 rabbits, a self-inflatable soft tissue expander was placed under the lateral mandibular periosteum via an extra-oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft and deproteinized bovine bone mineral (DBBM)(Bio-Oss(®)) were placed in the expanded area and covered by a titanium mesh. The bone and DBBM were separated in two compartments under the mesh with a collagen membrane in between. The mesh was then covered with a collagen membrane. After 3 months, the animals were sacrificed and specimens were collected for histology. RESULTS The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, no soft tissue dehiscence was recorded. The mean bone fill was 58.1±18% in the bone grafted area and 56.9±13.7% in the DBBM area. There was no significant difference between the autologous bone graft and the DDBM under the titanium mesh with regard to the total bone area or the mineralized bone area. Scanning electron microscopy showed that new bone was growing in direct contact with the DBBM particles and the titanium mesh. There is a soft tissue ingrowth even after soft tissue expansion and protection of the titanium mesh with a collagen membrane. CONCLUSION This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue, and that new bone can subsequently be generated under a titanium mesh with the use of an autologous bone graft or DBBM.

OBJECTIVES To evaluate the extent of bone fill over 3 years following the surgical treatment of peri-implantitis with bone grafting with or without a membrane. MATERIAL AND METHODS In a non-submerged wound-healing mode, 15 subjects with 27 implants were treated with a bone substitute (Algipore(®)) alone and 17 subjects with 29 implants were treated with the bone substitute and a resorbable membrane (Osseoquest(®)). Implants with radiographic bone loss ≥1.8 mm following the first year in function and with bleeding and/or pus on probing were included. Following surgery, subjects were given systemic antibiotics (10 days) and rinsed with chlorhexidine. After initial healing, the subjects were enrolled in a strict maintenance programme. RESULTS Statistical analysis failed to demonstrate changes in bone fill between 1 and 3 years both between and within procedure groups. The mean defect fill at 3 years was 1.3 ± (SD) 1.3 mm if treated with the bone substitute alone and 1.6 ± (SD) 1.2 mm if treated with an adjunct resorbable membrane,(p=0.40). The plaque index decreased from approximately 40-10%, remaining stable during the following 2 years. CONCLUSION Defect fill using a bone substitute with or without a membrane technique in the treatment of peri-implantitis can be maintained over 3 years.

PURPOSE The aims of the current study were to:(1) evaluate the results of vertical guided bone regeneration (GBR) with particulate autogenous bone grafts,(2) determine clinically and radiographically the success and survival rates of 82 implants placed in such surgical sites after prosthetic loading for 12 to 72 months, and (3) compare defects that were treated simultaneously with sinus augmentation and vertical GBR to other areas of the jaw treated with vertical GBR only. MATERIALS AND METHODS Eighty-two implants were inserted in 35 patients with 36 three-dimensional vertical bone defects. The patients were divided into three groups: single missing teeth (group A), multiple missing teeth (group B), and vertical defects in the posterior maxilla only (group C). All group C subjects were treated simultaneously with sinus and vertical augmentations. All patients were treated with vertical ridge augmentation utilizing titanium-reinforced polytetrafluoroethylene (e-PTFE) membranes and particulated autografts. After removal of the e-PTFE membrane, all sites received a collagen membrane. RESULTS At membrane removal, mean vertical augmentation was 5.5 mm (+/-2.29 mm). Mean combined crestal remodeling was 1.01 mm (+/-0.57 mm) at 12 months, which remained stable through the 6-year follow-up period. There were no statistically significant differences between the three groups in mean marginal bone remodeling. One defect had a bone graft complication (2.78%, 95% CI: 0.00%, 8.15%). The overall implant survival rate was 100% with a cumulative success rate of 94.7%. CONCLUSIONS (1) Vertical augmentation with e-PTFE membranes and particulated autografts is a safe and predictable treatment;(2) success and survival rates of implants placed in vertically augmented bone with the GBR technique appear similar to implants placed in native bone under loading conditions;(3) success and failure rates of implants placed into bone regenerated simultaneously with sinus and vertical augmentation techniques compare favorably to those requiring only vertical augmentation.

AIM The study was designed to evaluate the clinical treatment outcome of placing transmucosal implants into extraction. The purpose of the present clinical study was to test whether peri-implant bone defects can successfully be filled by applying both the bone and the bioresorbable materials for the guided tissue regeneration. METHODS Twelve patients who required extraction of a single molar were treated with immediate placement of an ITI implant (Dental Implant System). Guided bone regeneration (GBR) technique was always applied simultaneously using deproteinized bovine bone mineral. Implants and bone were covered with a resorbable collagen membrane. Clinical measurements were taken at 6 sites around each implant. Radiological and clinical parameters were measured at the time of implant placement and at follow-up after 1, 3, 6, 12 and 24 months. Prosthetic rehabilitation was performed 3 months after surgery using a porcelain fused to metal crown. RESULTS Soft tissue healing, at all sites, was free of complications, independently on the width of bone defect. Radiographs showed strength contact between peri-implant bone and the fixture without any defect between bone and implant. Clinical examination showed absolute implant stability complying with Albrekts-son's requirements. CONCLUSIONS The use of GBR with resorbable membrane to cover Bio-oss, in association with immediate implant insertion at posterior sites when there is a wide bone defect, also allows early defect filling and good stability, already in the first month, with the possibility of prosthetic loading after only 3 months.

Objectives: The aim of the present study was to evaluate immunohistochemically the pattern of guided bone regeneration (GBR) using different types of barrier membranes. Material and methods: Standardized buccal dehiscence defects were surgically created following implant bed preparation in 12 beagle dogs. Defects were randomly assigned to six different GBR procedures: a collagen-coated bone grafting material (BOC) in combination with either a native, three cross-linked, a titanium-reinforced collagen membrane, or expanded polytetrafluorethylene (ePTFE), or BOC alone. After 1, 2, 4, 6, 9, and 12 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin - OC, transglutaminase II - angiogenesis) and histomorphometrical analysis [e.g., bone-to-implant contact (BIC), area of new bone fill (BF)]. Results: In general, angiogenesis, OC antigen reactivity, and new bone formation mainly arose from open bone marrow spaces at the bottom of the defect and invaded the dehiscence areas along the implant surface and BOC. At 4 weeks, membranes supporting an early transmembraneous angiogenesis also exhibited some localized peripheral areas of new bone formation. However, significantly increasing BIC and BF values over time were observed in all groups. Membrane exposure after 10-12 weeks was associated with a loss of the supporting alveolar bone in the ePTFE group. Conclusion: Within the limits of the present study, it was concluded that (i) angiogenesis plays a crucial role in GBR and (ii) all membranes investigated supported bone regeneration on an equivalent level.

BACKGROUND This study compared bone regeneration following guided bone regeneration with two bioabsorbable collagen membranes in saddle-type bone defects in dog mandibles. METHODS Three standardized defects were created, filled with bone chips and deproteinized bovine bone mineral (DBBM), and covered by three different methods: control = no membrane; test 1 = collagen membrane; and test 2 = cross-linked collagen membrane (CCM). Each side of the mandible was allocated to one of two healing periods (8 or 16 weeks). The histomorphometric analysis assessed the percentage of bone, soft tissue, and DBBM in the regenerate; the absolute area in square millimeters of the bone regenerate; and the distance in millimeters from the bottom of the defect to the highest point of the regenerate. RESULTS In the 8-week healing group, two dehiscences occurred with CCM. After 8 weeks, all treatment modalities showed no significant differences in the percentage of bone regenerate. After 16 weeks, the percentage of bone had increased for all treatment modalities without significant differences. For all groups, the defect fill height increased between weeks 8 and 16. The CCM group showed a statistically significant (P = 0.0202) increase over time and the highest value of all treatment modalities after 16 weeks of healing, CONCLUSIONS The CCM showed a limited beneficial effect on bone regeneration in membrane-protected defects in dog mandibles when healing was uneventful. The observed premature membrane exposures resulted in severely compromised amounts of bone regenerate. This increased complication rate with CCM requires a more detailed preclinical and clinical examination before any clinical recommendations can be made.

The aim of this study was to immunohistochemically investigate bone regeneration following application of either hydroxyapatite+beta tricalcium phosphate (BCG) or a collagen-coated natural bone mineral (BOC) in combination with a collagen membrane at dehiscence-type defects in dogs. Standardized buccal dehiscence defects were surgically created following implant bed preparation in six beagle dogs. Defects were randomly filled with either BOC (BioOss Collagen((R))) or BCG (Bone Ceramic((R))) according to a split-mouth design, and covered with a native porcine derived collagen membrane (BioGide((R))). After 1, 4 and 9 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin) and histomorphometrical analysis (residual defect length, new bone-implant contact, area of new bone fill, percentage of osseointegrated bone-graft particles). Both groups revealed a significant decrease in mean residual defect length, and increases in mean new bone-implant contact, bone fill and percentage of osseointegrated bone-graft particles after 4 and 9 weeks of healing. Remaining BCG and BOC granules were completely integrated into a secondarily formed network of spongiosa, but there was no osteoclastic activity at the surface of either type of bone-graft particle. Both BCG and BOC may provide an osteoconductive scaffold to support guided bone regeneration procedures at dehiscence-type defects.

The purpose of this study was to evaluate the percentage of bone-to-implant contact following guided bone regeneration using expanded polytetrafluoroethylene (e-PTFE) membranes and various bone fillers in a beagle dog model. A staged approach was used for initial bone regeneration of surgically created defects and subsequent implant placement in newly regenerated ridges. Three months after bilateral extraction of the mandibular premolars and first molars, rectangular, distal-extension defects that included the entire width of the ridge buccolingually were surgically created in the alveolar processes. All defects were covered with an e-PTFE membrane, and several bone fillers were placed, in a randomized fashion, under the membrane: autogenous bone, demineralized freeze-dried bone, anorganic bovine bone, tricalcium phosphate granules, and collagen sponge. One site in each animal was treated with e-PTFE barrier membrane alone as control. Following an 8-month healing period, nonsubmerged titanium implants (36 total) were placed in regenerated bone following membrane removal. Three months later, the animals were sacrificed, and nondecalcified buccolingual sections were evaluated histometrically for bone-to-implant contact. All sites demonstrated high percentages (50% to 65%) of bone-to-implant contact, with no significant differences across the various treatment groups. In addition, all tested bone fillers formed a complex that supported and maintained the osseointegrated implants in a healthy state, with no apparent signs of peri-implantitis. Using a staged approach, the present study provided histologic and histometric evidence that implants placed in entirely regenerated bone can achieve and maintain osseointegration, regardless of the type of bone fillers used.

PURPOSE The purpose of this prospective clinical trial was to monitor the outcomes of periradicular surgery in large periapical lesions with or without guided tissue regeneration (GTR) and anorganic bovine bone. MATERIALS AND METHODS All teeth in the study revealed a periradicular lesion measuring at least 10 mm. A total of 63 teeth in 44 patients were included according to specific selection criteria. In the test group, after root end filling was completed, the defect was filled with anorganic bovine bone and was covered with a resorbable collagen membrane. In the control group, neither graft nor membrane was used. RESULTS A total of 59 teeth in 41 patients were evaluable at 1-year follow-up. Of these, 24 teeth belonged to the test group and 35 to the control group. Overall, 46 teeth (78%) had successfully healed, 10 (16.9%) demonstrated uncertain healing, and 3 exhibited treatment failure. Investigators found no statistically significant differences in outcome between test and control groups. CONCLUSIONS The present study showed that the use of GTR in association with anorganic bovine bone in the treatment of patients with large periradicular lesions of strictly endodontic origin has no beneficial effect on outcome.