Dental Implants in 18 Patients with Systemic Scleroderma: A Retrospective Radiographic Analysis Over a 5-Year Period with Focus on Marginal Bone Loss.

PURPOSE: Patients with systemic scleroderma (SSc) often suffer from premature tooth loss. The aim of this study was to radiologically investigate bone loss at dental implants in patients with SSc and compare it with data from the literature on healthy patients. MATERIALS AND METHODS: Mesial and distal bone level changes at implants were independently determined on panoramic and intraoral radiographs. They were double-checked after determination of evaluability by three different raters. Cohen's kappa was used to test for interrater reliability. Mean bone loss was estimated using linear regression analysis considering the patient as a random-effect implant and performed separately in predefined implant regions for different time points and for the mesial and distal sides of the implants. RESULTS: Mesial and distal bone level changes were analyzed in 61 implants using periapical and panoramic radiographs. In total, 114 radiographs from 18 patients were evaluable in both the mesial and distal regions. After a maximum observation period of 60 months, the mean peri-implant bone loss was 1.68 mm (range: 0.83 to 2.54 mm) at the distal aspect and 1.65 mm (range: 0.81 to 2.48 mm) at the mesial aspect in the right posterior mandible (region 44 to 47 [FDI numbering system]), whereas in the left posterior maxilla (regions 24 to 27), the mean peri-implant bone loss was 0.61 mm (range: 0.32 to 0.91 mm) at the distal aspect and 0.59 mm (range: 0.16 to 1.03 mm) at the mesial aspect. The mean bone loss 60 months after surgery was 1.05 mm (range: 0.85 to 1.25 mm). CONCLUSIONS: Marginal bone loss at implants in patients with SSc is comparable to data from the literature collected in healthy subjects.

Dental implants in patients suffering from systemic sclerosis: a retrospective analysis of clinical outcomes in a case series with 24 patients.

PURPOSE: Patients with systemic sclerosis (SSc) often suffer from premature tooth loss. This is a retrospective case series of patients with systemic sclerosis who were treated with dental implants. METHODS: SSc patients treated with at least one dental implant between 5 August 1998 and 31 December 2018 were included in this long-term retrospective study. The primary study variables were the plaque index (PLI), sulcus bleeding index (SBI), peri-implant pocket depth (PPD) and interincisal distance (ID). The test for marginal homogeneity analysed whether the SBI and PLI values changed between examination and follow-up. A linear regression was performed for the PPD measurement. The rank correlation coefficient compared the SBI with the PLI and the PPD with the PLI. The survival rate data for the implants were analysed by the Kaplan-Meier procedure. P < .05 was considered significant. RESULTS: Twenty-four patients [(age: mean 59.6 years (SD ± 13.08)] received a total of 72 implants. ID resulted in a mean value of 29.54 mm (SD ± 6.4 mm). The mean value of the PPD was between 2.4 mm and 2.8 mm. A comparison of the SBI with the PLI and the PPD with the PLI showed a significantly positive correlation between the SBI and the PLI and between the PPD and the PLI. The correlation between the PPD and the PLI (Spearman rho: 0.36, p < 0.001) was less pronounced than that between the SBI and the PLI (Spearman rho: 0.61, p < 0.001). Kaplan-Meier analysis showed a post-10-year implant survival rate of 87.6% (95%-KI: 75.5-94.0). CONCLUSION: Implant-supported oral rehabilitation can be carried out and maintained successfully in SSc patients.

Prevalence of Oral and Maxillofacial Disorders in Patients with Systemic Scleroderma-A Systematic Review.

BACKGROUND: Systematic scleroderma is a rare chronic autoimmune disease of unknown aetiology. The aim of this study was to identify the prevalence of orofacial pathognomonic conditions in patients with systemic scleroderma using only randomised prospective studies that investigated the treatment of oral and maxillofacial changes, highlighted associations between the disease and Sjogren's syndrome, and/or analysed the effect of oral hygiene. METHODS: The literature was systematically reviewed based on Cochrane Library, EMBASE, PubMed, Scopus, and Web of Science articles published up to March 2020. The primary endpoint of this analysis was defined as an estimation of the prevalence of oral mucosal changes in different areas of the oral cavity (oral mucosa, tongue, lip, periodontal status, bones, and other regions) in patients suffering from scleroderma. Therefore, a systematic literature search (Cochrane Library, EMBASE, PubMed, Scopus, and Web of Science) was conducted and limited by the publication date (1950-03/2020) and the publication language (English). Extracted frequencies were pooled using methods for meta-analysis. In order to obtain the highest level of evidence, only prospective study reports were considered to be eligible. RESULTS: After full-text screening, 14 (766 patients) out of 193 publications were eligible for the final analysis. Twelve studies produced reliable results in the final data sets. Calculation of the pooled effect estimate (random effects model) revealed a prevalence of 57.6% (95% CI: 40.8-72.9%) for the main area "lip". For the area "oral mucosa", a prevalence of 35.5% (95% CI: 15.7-62.0%) was calculated. The prevalence for "other regions" was only based on studies with salivary changes and was calculated to be 25.4% (95% CI: 14.2-41.3%). CONCLUSION: The most pathognomonic conditions in the orofacial region in patients with systemic scleroderma affect the lips, oral mucosa, and salivary glands.

Guided implant surgery for one-piece ceramic implants: a digital workflow.

BACKGROUND: Accurate implant placement in the bone is key to successful implant treatment. Once inserted, it can be difficult to correct the orientation of the implant axis, especially of a one-piece implant. Prosthetic-driven digital implant planning in combination with fully guided implant surgery can offer additional safety in such cases. CASE PRESENTATION: The patient presented with a wide, edentulous interdental space extending from sites 13 to 16, which was to be restored with three one-piece zirconia implants supporting a zirconia fixed partial denture comprizing a cantilever to the mesial aspect. Digital planning based on DICOM (Digital Imaging and Communications in Medicine) and intraoral surface data was performed to ensure optimal positioning. Guided implant placement was executed using a contra-angle handpiece with special attachments and a compatible, sleeveless drill guide. Impressions of the implants for the final restoration were acquired using an intraoral scanner. Reflection-related errors were compensated for by using the given digital abutment geometry. The DICOM and STL datasets were superimposed and used as the basis for fabricating a monolithic zirconia restoration through a subtractive milling process. The final restoration was adhesively cemented. CONCLUSIONS: By using a prosthetic-driven implant planning strategy, it was possible to place the one-piece ceramic implants without an available implant manufacturer's guide-based solution. This was accomplished using a contra-angle surgical handpiece with special attachments and a compatible drill guide. This approach is particularly recommended for the placement of one-piece implants, which otherwise require irreversible abutment grinding for the adjustment of the implant axis orientation after placement. To increase the precision of the digital impressions of the implants, the ideal abutment geometry was imported and superimposed onto the scan data. The results demonstrate that the proposed method can dispense with the need for gingival retraction when acquiring impressions for implants of this type in the future.

Premature exposure of dental implant cover screws. A retrospective evaluation of risk factors and influence on marginal peri-implant bone level changes.

OBJECTIVES: The objectives of this study were to identify risk factors associated with the premature cover screw exposure (pCSE) at dental implants and to evaluate the influence of a pCSE on peri-implant marginal bone level (MBL) change compared to non-exposed implants. MATERIALS AND METHODS: Retrospective data assessment from 165 patients (mean age = 54.0 ± 14.4 years) who received 395 submerged implants included demographic, health-related, and therapeutic variables which were analyzed for their respective impact. MBL change was detected at digital radiographs obtained from first- and second-stage surgeries. RESULTS: pCSE were detected in 43 patients (26.1%) and 53 implants (13.4%). An increased frequency of exposure was significantly associated with (I) male gender (p = 0.012) at patient level and (II) the posterior region of the jaws (p = 0.005), implant systems with platform-matching cover screws, and a vertical distance of ≥0.5 mm between bone crest and the implant platform (both p < 0.001) at implant level. The decrease in mesial, distal, and total MBL differed significantly (mean total = 0.8 ± 0.7 vs. 0.3 ± 0.5; mean mesial = 0.8 ± 0.8 vs. 0.3 ± 0.6; mean distal = 0.8 ± 0.8 vs. 0.3 ± 0.6 mm; p < 0.001) between non-exposed and pCSE implants. CONCLUSIONS: Male patients, implants with platform-matched cover screws, or when placed supracrestally or in posterior sites revealed significantly more pCSE, resulting in significantly decreased peri-implant MBL compared with non-exposed implants. CLINICAL RELEVANCE: Patients with an enhanced risk of pCSE should follow frequent regular recalls during the healing period to enable for early diagnosis and intervention.

Sinus Floor Elevation and Augmentation Using Synthetic Nanocrystalline and Nanoporous Hydroxyapatite Bone Substitute Materials: Preliminary Histologic Results.

PURPOSE: To compare the tissue composition of augmented sites after using two different synthetic bone substitute materials, nanocrystalline and nanoporous hydroxyapatite (HA), for sinus floor elevation and augmentation. MATERIALS AND METHODS: Forty-four patients received 88 titanium screw implants (Camlog Promote plus) of 4.3-mm diameter and 11- or 13-mm length, placed simultaneously during sinus floor elevation and augmentation. Nanocrystalline (Ostim) or nanoporous (NanoBone) HA were used exclusively. Bone substitute materials and implant lengths were allocated by randomization. Bone biopsy specimens were obtained from the former area of the lateral access window at implant exposure during healing abutment placement after 6 months. Biopsy specimens were prepared and examined histologically and histomorphometrically. RESULTS: All implants were osseointegrated at the time of exposure. Clinically and histologically, no signs of inflammation in the augmented sites were present. The histomorphometric analysis of 44 biopsy specimens revealed 31.8% ± 11.6% newly formed bone for sites augmented with nanocrystalline HA and 34.6% ± 9.2% for nanoporous HA (P = .467). The proportion of remaining bone substitute material was 28.4% ± 18.6% and 30% ± 13%, respectively (P = .453). The proportion of soft tissue within the biopsy specimens was 39.9% ± 11.1% and 35.4% ± 6.8%, respectively (P = .064). No significant differences were found between the area fractions of bone, bone substitute material, and soft tissue concerning the bone substitute material utilized. CONCLUSION: Within the present study, both synthetic bone substitute materials, nanocrystalline and nanoporous HA, were found to support bone formation in sinus floor elevation and augmentation procedures by osteoconductivity. They were not completely resorbed after 6 months. The amounts of newly formed bone, soft tissue, and bone substitute material remnants were found to be similar, indicating that both materials are likewise suitable for sinus floor elevation and augmentation procedures.

Local, systemic, demographic, and health-related factors influencing pathogenic yeast spectrum and antifungal drug administration frequency in oral candidiasis: a retrospective study.

OBJECTIVES: In order to identify oral candidiasis patients being at risk of carrying potentially drug-resistant Candida, the aim of the study was to detect local, systemic, demographic, and health-related factors influencing (I) yeast spectrum composition and (II) antifungal administration frequency. Additionally, the aim was to investigate (III) species shift occurrence. MATERIALS AND METHODS: Data from 798 patients (496 females, 302 males; mean age 59.7) with oral candidiasis diagnosed based on positive clinical and microbial findings (species identification and CFU count) between 2006 and 2011 were retrospectively analyzed using Pearson's chi(2) test and regression analysis. RESULTS: Among 958 isolates, Candida albicans was the most frequently detected (76.8 %). Also, species intrinsically resistant to azoles were frequently isolated (15.8 and 17.7 % of isolates and patients). (I) Infections only caused by C. albicans were significantly associated with the use of inhalation steroids (p = 0.001) and antibiotics (p = 0.04), super-infection of lichen planus (p = 0.002), and the absence of removable dentures (p < 0.001). (II) Anti-mycotics were significantly more frequently administered in patients using inhalation steroids (p = 0.001), suffering from asthma/COPD, or smoking heavily (p = 0.003) and if C. albicans and non-albicans species were detected together (p = 0.001). (III) Pathogen composition did not change over time within the examined period (p = 0.239). CONCLUSIONS: Different variables enhance the presence of certain Candida and the antifungal prescription frequency. No species shift was evident. CLINICAL RELEVANCE: The major pathogen in oral candidiasis remains C. albicans. Nevertheless, therapeutic problems may be caused by the frequent presence of species intrinsically resistant to azoles, especially in patients wearing dentures.

Impact of platform switching on marginal peri-implant bone-level changes. A systematic review and meta-analysis.

OBJECTIVE: To address the focused question, is there an impact of platform switching (PS) on marginal bone level (MBL) changes around endosseous implants compared to implants with platform matching (PM) implant-abutment configurations? MATERIAL AND METHODS: A systematic literature search was conducted using electronic databases PubMed, Web of Science, Journals@Ovid Full Text and Embase, manual search for human randomized clinical trials (RCTs) and prospective clinical controlled cohort studies (PCCS) reporting on MBL changes at implants with PS-, compared with PM-implant-abutment connections, published between 2005 and June 2013. RESULTS: Twenty-two publications were eligible for the systematic review. The qualitative analysis of 15 RCTs and seven PCCS revealed more studies (13 RCTs and three PCCS) showing a significantly less mean marginal bone loss around implants with PS- compared to PM-implant-abutment connections, indicating a clear tendency favoring the PS technique. A meta-analysis including 13 RCTs revealed a significantly less mean MBL change (0.49 mm [CI95% 0.38; 0.60]) at PS implants, compared with PM implants (1.01 mm [CI95% 0.62; 1.40] (P < 0.0001). CONCLUSIONS: The meta-analysis revealed a significantly less mean MBL change at implants with a PS compared to PM-implant-abutment configuration. Studies included herein showed an unclear as well as high risk of bias mostly, and relatively short follow-up periods. The qualitative analysis revealed a tendency favoring the PS technique to prevent or minimize peri-implant marginal bone loss compared with PM technique. Due to heterogeneity of the included studies, their results require cautious interpretation.

Impact of implant-abutment connection, positioning of the machined collar/microgap, and platform switching on crestal bone level changes. Camlog Foundation Consensus Report.

OBJECTIVES: The aim of this consensus meeting was to assess the impact of implant-abutment connection, positioning of the machined collar/microgap, and platform switching on crestal bone level changes. MATERIALS AND METHODS: Two comprehensive systematic reviews were prepared in advance of the meeting. Consensus statements, practical recommendations, and implications for future research were based on within group as well as plenary scrutinization and discussions of these systematic reviews. RESULTS: Placing the smooth part of the implant below the alveolar crest may lead to bone loss. Despite a more pronounced bone remodeling, the subcrestal positioning of the microgap may help to retain the bony coverage of the rough surface. Crestal bone remodeling has been observed for either internal and external, or conical and butt-joint connections. There was a trend favoring the platform switching concept to prevent or minimize peri-implant marginal bone loss. CONCLUSIONS: Future research should consider an uniform and comparable study design, either excluding or exactly documenting possible confounding factors.

Implant-prosthetic rehabilitation of the edentulous maxilla and mandible with immediately loaded implants: preliminary data from a retrospective study, considering time of implantation.

PURPOSE: This study sought to evaluate treatment outcomes of implant-prosthetic rehabilitation with implants in the edentulous maxilla or mandible that were immediately loaded by fixed prostheses. Special consideration was given to the time of implantation (immediate, delayed, or late implant placement). MATERIALS AND METHODS: Twenty-five patients who received 283 immediately loaded screw-type implants were included in this retrospective study. Data captured included patient file information, panoramic and periapical radiographs obtained during treatment, and clinical parameters examined during the recall period. Clinical and radiographic status of peri-implant soft and hard tissue was evaluated, as well as the function of prostheses and subjective assessment by the patients of the treatment. Survival/success rates were analyzed with respect to the time of implantation. RESULTS: Following a maximum observation period of 120 months (median 29 months) postimplantation and subsequent immediate functional loading, implant survival was 99.6% (one implant failed after 20 months). The success rates were 98.2% for implants and 88% for patients; five implants in three patients did not meet success criteria. Neither the implant site nor the time of implantation were associated with unsuccessful outcomes. Implant-related evaluations revealed a significant association between implant success and implant length of 10 mm or less (P < .018). CONCLUSION: Within the limits of this study, immediate loading of rough-surfaced, screw-type implants supporting fixed dentures for the treatment of edentulous maxilla or mandible appears to be a reliable treatment option with a high probability of success. The time of implantation did not influence implant survival or success rates.

Lateral alveolar ridge augmentation using a synthetic nano-crystalline hydroxyapatite bone substitution material (Ostim): preliminary clinical and histological results.

OBJECTIVES: The purpose of this preliminary two-center clinical prospective study was to evaluate the tissue composition of augmented sites after the use of a nano-crystalline hydroxyapatite (ncHA) bone substitution material by clinical and histological examinations. MATERIAL AND METHODS: A synthetic ncHA augmentation material was used without any additives in 14 patients requiring lateral ridge augmentation 6-7 months before (10 patients) or at implant placement (four patients). The ncHA material was covered by a titanium mesh for space maintenance. Clinical and radiographic parameters were evaluated and bone biopsy cores, obtained 6-7 months following augmentation, were assessed histologically and histomorphometrically. RESULTS: One patient showed gingival swelling, redness and pain at the augmentation site requiring removal of the titanium mesh 6 weeks postoperatively. In seven patients, a premature exposure of the titanium mesh without any inflammatory symptoms was noted. The width of the fixed gingival and the alveolar ridge height did not change significantly at least 6 months following augmentation (P>0.5), whereas a significant gain in alveolar ridge width (P=0.01) was noted. After a median period of prosthetic loading of 24 months, no implant was considered to be a failure. Histology revealed ncHA remnants in peripheral and central parts of biopsy cores obtained from seven patients after at least 6 months without histological symptoms of inflammation, whereas histomorphometry of bone cores revealed no significant differences of the mean percentage area of ncHA in peripheral (23.4%) and central (15.1%) parts of biopsy cores (P=0.262). The mean percentage area of bone colonizing the defect was 52.3%. CONCLUSIONS: Small amounts of ncHA were found after at least 6 months in bone biopsies. The former defect space was filled with bone. The alveolar ridge width gain was found to be significant after lateral augmentation utilizing ncHA, providing a quantitatively and qualitatively sufficient site for primary stable implant placement.

Oral rehabilitation using Camlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface. Results from a prospective study with special consideration of short implants.

OBJECTIVES: The purpose of the present clinical study was to report on the clinical performance of screw-cylinder implants with special consideration of the survival rate of short implants. MATERIAL AND METHODS: In this prospective study with consecutive patient recruitment, Camlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface and a triple-cam tube-in-tube implant-abutment connection have been used only. Two groups of implants were evaluated: implants of 9 and 11 mm in length were considered short, those of 13 and 16 mm were considered long. Besides clinical and radiographic parameters, data of complications, patients' subjective evaluation of treatment outcome, general medical history and smoking habits were recorded. RESULTS: Three hundred and thirty-three Camlog screw-cylinder implants were inserted in 133 patients. One hundred and twenty-nine patients were available for follow-up, representing 325 implants. The median observation period was 33 months (Q(25%) 26; Q(75%) 38). After a maximum observation period of 55 months, the Kaplan-Meier-survival analysis revealed no significant difference between the mean survival probabilities of 98.3% (n=59, patient-related) of short implants, and of 95.7% of long implants (n=70, patient-related) (P=0.162). No significant difference was found between implant survival rates considering maxilla (98.7%) and mandible (98.2%). A stratified analysis of short implants revealed a significant influence of premature cover screw exposures (P=0.02) and smoking (P=0.008) on implant survival. These influences were not found significant for long implants. CONCLUSIONS: The prognosis of short Camlog implants is comparable with that of long implants. Therefore, their clinical use instead of performance of sophisticated vertical augmentation procedures before installation of long implants might be considered as alternative treatment option. In smokers, the use of short implants should be considered cautiously, however. The risk of premature cover screw exposure should be minimized.

Smoking interferes with the prognosis of dental implant treatment: a systematic review and meta-analysis.

AIM: This systematic literature review was performed to investigate if smoking interferes with the prognosis of implants with and without accompanying augmentation procedures compared with non-smokers. METHODS: A systematic electronic and handsearch (articles published between 1989 and 2005; English and German language; search terms "dental or oral implants and smoking"; "dental or oral implants and tobacco") was performed to identify publications providing numbers of failed implants, related to the numbers of smokers and non-smokers for meta-analysis. Publications providing statistically examined data of implant failures or biologic complications among smokers compared with non-smokers were included for systematic review. RESULTS: Of 139 publications identified, 29 were considered for meta-analysis and 35 for systematic review. Meta-analysis revealed a significantly enhanced risk for implant failure among smokers [implant-related odds ratio (OR) 2.25, confidence interval (CI(95%)) 1.96-2.59; patient-related OR 2.64; CI(95%) 1.70-4.09] compared with non-smokers, and for smokers receiving implants with accompanying augmentation procedures (OR 3.61; CI(95%) 2.26-5.77, implant related). The systematic review indicated significantly enhanced risks of biologic complications among smokers. Five studies revealed no significant impact of smoking on prognosis of implants with particle-blasted, acid-etched or anodic oxidized surfaces. CONCLUSION: Smoking is a significant risk factor for dental implant therapy and augmentation procedures accompanying implantations.

Retrospective evaluation of the success of oral rehabilitation using the Frialit-2 implant system. Part 1: Influence of topographic and surgical parameters.

PURPOSE: This retrospective longitudinal study evaluated the success of implant-prosthetic rehabilitation with the Frialit-2 implant system. MATERIALS AND METHODS: The study was performed with 504 patients, from two treatment centers, who had received a total of 1,554 implants between May 1990 and May 2001. The data of these patients, who received the implants in various regions and for various indications, were analyzed with respect to clinical, topographic, and radiographic parameters. The mean observation period was 6.2 years, with a maximum of 134 months. RESULTS: A survival rate of 94.8% was found for all implants. The implant survival rate of 92.6% in the maxilla remained constant after 68 months of observation. In the mandible, the implant survival rate of 96.7% showed no changes after 76 months. Kaplan-Meier analysis identified jaw, occurrence of postoperative complications, and region as statistically significant factors influencing implant survival. Multivariate Cox regression showed that gender, occurrence of postoperative complications, and jaw were factors that increased the risk of implant loss. Statistically significant correlations were found between the incidence of implant loss and vertical bone loss adjacent to the implant at the time of second-stage surgery. CONCLUSION: Implant survival rate is influenced by implant site, gender, and occurrence of complications. On the whole, the Frialit-2 system proved successful in all areas of indication after long-term observation.

Patient's informed consent prior to implant-prosthetic treatment: a retrospective analysis of expert opinions.

PURPOSE: The purpose of this retrospective analysis of expert opinions was to optimize the level of patient information prior to implant-prosthetic treatment. MATERIALS AND METHODS: Twenty-eight expert opinion reports on implant treatment cases compiled between 1996 and August 2001 were analyzed. RESULTS: Seventy-five percent of all cases subjected to expert opinion reports revealed generally inadequate patient information. Significant associations were found between diagnostic mistakes and a lack of or inadequate information about complications that occurred (P = .04). Inadequate prosthetic or periodontal pretreatment of the patient prior to implant treatment was associated with a lack of information concerning implant and periodontal maintenance (P = .023) as well as insufficient oral hygiene status (P = .001). DISCUSSION: In addition to a general lack of patient information, a lack of information about possible complications and inadequate information about treatment risks, treatment costs, and treatment alternatives were also found. CONCLUSION: Optimization of pretreatment information for patients, as well as improvement of communication with patients throughout the whole treatment and maintenance period, seem to be necessary.

Peri-implant alveolar bone loss with respect to bone quality after use of the osteotome technique: results of a retrospective study.

Knife-edge configurations or non space-maintaining defects of the alveolar ridge limit the indications for implant-prosthetic rehabilitation. If ridge expansion is required, bone splitting and bone spreading techniques may be applied. Summers introduced a modified approach for ridge expansion by osteotome technique. The principles of this nonablative implant bed preparation technique are lateral and apical bone relocation and condensation. The peri-implant alveolar bone loss after use of the osteotome technique was evaluated radiographically with respect to the bone quality in 22 patients with 22 implants. Differences between the alveolar crest and the implant shoulder in radiographs obtained immediately after implant insertion, after the end of unloaded healing period and after different periods of functional loading were calculated. The osteotome technique was used in bone quality classes 2 and 3, respectively, according to the Lekholm and Zarb classification. Two implants failed. Significant differences were found between the bone levels after implant insertion and at the end of the healing period as well as after functional loading (P = 0.028). The bone quality was significantly correlated (r = - 0.505; P = 0.023) with the change of the peri-implant marginal bone height level 6 months after the implant installation. The present data indicate the importance of bone quality evaluation before application of the osteotome technique.

Histological assessment of augmented jaw bone utilizing a new collagen barrier membrane compared to a standard barrier membrane to protect a granular bone substitute material.

Successful bone augmentation requires predictable space maintenance and adequate exclusion of those cells that lack osteogenetic potential from the defect area. Natural bone mineral is considered to be osteoconductive and is used as space maker in combination with membrane barrier techniques. The aim of this study was to compare qualitative histological results achieved by using deproteinized bovine bone mineral (DBBM) as a space maintainer and a new collagen barrier (Ossix, test group) vs. the same bone substitute and the standard e-PTFE membrane (Gore-Tex), control group). Twenty-eight patients were randomly assigned to the test or the control group. Seven months after augmentation procedures, biopsies were obtained at reentry and were analysed histomorphometrically. In all, 14 specimens of group I (test group, Ossix) and 13 specimens of group II (controls, PTFE-membranes) showed close qualitative similarity of their histologies. Histomorphometrically, total mineralized bone area was 42% +/- 18% in group I vs. 39% +/- 15% in group II. The unmineralized tissue area was 44% +/- 15% vs. 46% +/- 12% and the area of DBBM remnants 14% +/- 9% and 15% +/- 12%, respectively. The differences were statistically nonsignificant (Mann-Whitney test). The occurrence of barrier exposure did not interfere with the histological outcome either in the test or in the control group. The new collagen barrier combined with the DBBM provided qualitative bone regeneration comparable to the standard e-PTFE material combined with the same mineral.