Indications for implant-supported rehabilitation of the posterior atrophic maxilla: A multidisciplinary consensus among experts in the field utilising the modified Delphi method.

PURPOSE: To establish consensus-driven guidelines that could support the clinical decision-making process for implant-supported rehabilitation of the posterior atrophic maxilla and ultimately improve long-term treatment outcomes and patient satisfaction. MATERIALS AND METHODS: A total of 33 participants were enrolled (18 active members of the Italian Academy of Osseointegration and 15 international experts). Based on the available evidence, the development group discussed and proposed an initial list of 20 statements, which were later evalu-ated by all participants. After the forms were completed, the responses were sent for blinded ana-lysis. In most cases, when a consensus was not reached, the statements were rephrased and sent to the participants for another round of evaluation. Three rounds were planned. RESULTS: After the first round of voting, participants came close to reaching a consensus on six statements, but no consensus was achieved for the other fourteen. Following this, nineteen statements were rephrased and sent to participants again for the second round of voting, after which a consensus was reached for six statements and almost reached for three statements, but no consensus was achieved for the other ten. All 13 statements upon which no consensus was reached were rephrased and included in the third round. After this round, a consensus was achieved for an additional nine statements and almost achieved for three statements, but no consensus was reached for the remaining statement. CONCLUSION: This Delphi consensus highlights the importance of accurate preoperative planning, taking into consideration the maxillomandibular relationship to meet the functional and aesthetic requirements of the final restoration. Emphasis is placed on the role played by the sinus bony walls and floor in providing essential elements for bone formation, and on evaluation of bucco-palatal sinus width for choosing between lateral and transcrestal sinus floor elevation. Tilted and trans-sinus implants are considered viable options, whereas caution is advised when placing pterygoid implants. Zygomatic implants are seen as a potential option in specific cases, such as for completely edentulous elderly or oncological patients, for whom conventional alternatives are unsuitable.

Lateral augmentation of the jaw by the split expansion ridge technique. A critical review.

Bone augmentation has become a routine procedure to enhance and/or repair a deficient or resorbed alveolar ridge for predictable and successful implant placement. The split expansion ridge i.e., the alveolar ridge splitting (ARS) procedure, is one of the less invasive procedures, and is characterized by minor morbidity. This would allow to widen narrow ridges in order to allow implant reconstruction in a sufficient bone volume. Its efficacy and long-term stability rely upon clinical opinions and long-term retrospective studies, while prospective comparative studies and randomized controlled trials are rare. This critical review presents the development of this technique, describes the surgical procedure, and provides technical notes and modifications. The learning curve and in-depth knowledge of the oral anatomy, as well as the recognition of incidence and management of complications are of utmost importance in the clinical application of the ARS procedure.

Stromal cells associated with soft tissue augmentation by a volume stable collagen matrix (VCMX) are predominated by anti-inflammatory/reparative macrophages.

Aim: To define immunophenotypes of stromal inflammatory and endothelial cells and fibroblasts 3-months post-augmentation of the peri-implant soft tissue using a porcine cross-linked collagen matrix (VCMX). Methods: Peri-implant soft tissue samples were obtained from 12 patients at the lining mucosa (LM) - masticatory mucosa (MM) junction, before and at 3-months post-augmentation. Immunohistochemical stains for identification of inflammatory cells [T (CD3) and B (CD20) lymphocytes, plasma cells (CD138)], macrophages (CD68-pro-inflammatory, CD163-anti-inflammatory/reparative), endothelial cells (CD31, CD34) and fibroblasts (CD90, TE-7), were performed. Differences in the mean positively-stained cells pre- and post-augmentation was analyzed by Wilcoxon Signed-Rank Test. Results: CD31+ endothelial cells showed increased mean numbers in MM2 compared to MM1 (p=0.025) and in LM2 compared to LM1 (p=0.047). CD163+ anti-inflammatory macrophages showed mean numbers in MM2 higher than MM1 (p=0.021) and in LM2 than LM1 (p=0.012). All other cell phenotypes showed insignificant changes between pre- and post-augmentation. Conclusion: This molecular study provided novel insight on the frequency of phenotypes of stromal cells in the wound healing process 3-months post-augmentation with VCMX, with anti-inflammatory CD163+ macrophages being predominant. This should be further investigated in order to find novel therapeutic approaches to modulate and promote the VCMX-related healing process.

Sinus augmentation procedure via the lateral window technique-Reducing invasiveness and preventing complications: A narrative review.

Sinus augmentation has become an integrated surgical phase in posterior maxillary implant prosthesis reconstruction. Since the residual alveolar bony height usually requires additional volume particularly at this anatomical region, sinus floor augmentation is advocated routinely. Over the years, Implant success rate is proved to be comparable to the one in the pristine bone, which is well documented in the literature. Anatomical aspects as well as surgeon skills are at most importance to achieve predictable outcome. In this narrative review, the different osteotomy techniques, the indications toward 1 or 2-stage approaches, the control of the Schneiderian membrane integrity as well as the management of intra- and post-operative complications are thoroughly discussed according the current data. In light of the excellent long-term implant success rate concurrent with the application of contemporary advanced techniques of the sinus augmentation via the lateral wall osteotomy approach, reduce invasiveness and less complication occurrences are well documented. A well-codified patient selection involving the rhinologist as an integral medical team would be significantly beneficial toward early diagnosis. In-depth knowledge of the anatomy, execution of a well standardized surgical technique, and understanding the complication etiology and their management are prerequisites for reducing patient morbidity to minimal discomfort and predictable successful outcome.

Radiographic protrusion of dental implants in the maxillary sinus and nasal fossae: A multidisciplinary consensus utilising the modified Delphi method.

The aim of the present study was to generate an international and multidisciplinary consensus on the clinical management of implant protrusion into the maxillary sinuses and nasal fossae. A total of 31 experts participated, 23 of whom were experts in implantology (periodontologists, maxillofacial surgeons and implantologists), 6 were otolaryngologists and 2 were radiologists. All the participants were informed of the current scientific knowledge on the topic based on a systematic search of the literature. A list of statements was created and divided into three surveys: one for all participants, one for implant providers and radiologists and one for otolaryngologists and radiologists. A consensus was reached on 15 out of 17 statements. According to the participants, osseointegrated implants protruding radiographically into the maxillary sinus or nasal fossae require as much monitoring and maintenance as implants fully covered by bone. In the event of symptoms of sinusitis, collaboration between implant providers and otolaryngologists is required. Implant removal should be considered only after pharmacological and surgical management of sinusitis have failed.

Contour Changes Following Implant Placement and Concomitant Soft Tissue Augmentation Applying a Volume-Stable Collagen Matrix.

The objective of this study was to assess volumetric and linear changes of buccal mucosal thickness at implant sites following soft tissue augmentation with a volume-stable collagen matrix (VCMX). Soft tissue augmentation using a VCMX was performed in 12 patients at the time of implant placement. Hydrocolloid impressions were taken prior to surgery and at 1 and 6 months postsurgery. Stone cast models were scanned, and stereolithography (STL) files from the three time points were uploaded to an image-analysis software. At all time points, linear and volumetric measurements of the contour changes up to 3 mm apical to the mucosal margin were performed and were analyzed statistically. At 1 mm apical to the mucosal margin, the change in soft tissue thickness between presurgery (T1) and 1 month (T2) amounted to 0.21 ± 1.22 mm, and the change between T1 and 6 months (T3) was 0.08 ± 1.47 mm. At 3 mm apical to the mucosal margin, the change in soft tissue thickness was 1.92 ± 1.70 mm between T1 and T2 and 0.31 ± 1.26 mm between T1 and T3. Contour (volumetric) changes revealed an increase of 0.58 ± 0.73 mm between T1 and T2 and an overall gain of 0.55 ± 0.73 mm between T1 and T3. Soft tissue augmentation with VCMX increased the ridge profile. The increase in ridge width was greater at 3 mm below the ridge crest than at 1 mm below the ridge crest. Remodeling processes during healing showed a decrease in the ridge contour between 1 and 6 months.

Autogenous Particulate Dentin in Socket Site Preservation Procedures: Histologic and Histomorphometric Observations.

PURPOSE: To evaluate the efficacy of autogenous particulate dentin as a bone substitute to maintain dimensional volume in human socket preservation procedures. MATERIALS AND METHODS: Particulate dentin was used in socket site preservation procedures. The extracted natural tooth was ground to particles 250 to 1,200 µm in size to fill the socket site. At 6 months, during the implant placement stage, hard tissue biopsy specimens were harvested by a 2.5-mm cylindrical trephine bur for the histologic analysis. Histomorphometry was carried out with ImageJ software to calculate direct bone to grafted dentin particles contact, newly formed bone, and particulate dentin area fractions. RESULTS: Fifteen patients went through the socket preservation procedure using particulate dentin as the grafted bone substitute. De novo bone formation filled the entire grafted area. Newly formed bone was observed throughout the entire grafted area, particularly around the grafted dentin particles. The majority of particles were surrounded by direct contact with newly formed osseous tissue enriched by osteocytes. Newly formed bone ankylosed to particulate dentin and became a solid matrix preserving the ridge dimension. Histomorphometric measurements showed that the new bone formation area fraction was on average 38.4% ± 16.5%, while the residual particulate dentin showed an average of 29.9% ± 14.4%, and 31.7% ± 14.2% was captured by the connective tissue component. Particulate dentin was in direct contact with newly formed bone at an average rate of 69.1% ± 22.8%. CONCLUSION: Particulate dentin showed complete biocompatibility and high osteoconduction. Thus, it can be used as an appropriate grafting biomaterial to maintain socket site volume dimensionally for subsequent implant placement procedures.

Histologic composition of marginal mucosal tissue augmented by a resorbable volume-stable collagen matrix in soft tissue thickening procedures in humans: a morphometric observational study.

AIM: This study aims to examine the composition of lining and masticatory mucosa at the pre- and post-soft tissue augmentation procedures with a volume-stable cross-linking collagen matrix (VCMX) in humans. MATERIALS AND METHODS: In 12 patients, single implant sites were augmented with a VCMX. Biopsies were obtained including masticatory (MM) and lining (LM) mucosa before augmentation and at 12 weeks post-augmentation procedures. Rete pegs density (RPD), length (RPL), and blood vessel density (BVD) were histomorphometrically analyzed at both time points. Picrosirius red staining under polarized light microscopy was used to evaluate collagen fiber organization. The effects of time and tissue type were evaluated by ANOVA with repeated measures. RESULTS: Both MM and LM areas demonstrated an increase in mean RPL following augmentation, 382.6 µm ± 95.1 vs. 290.5 µm ± 79.3 and 335.6 µm ± 94.2 vs. 292.9 µm ± 77.0, respectively (p < .05). There was a significant difference in the numbers of RP per 1 mm length (RPD) between the MM (9.2 ± 1.7) and LM (6.1 ± 2.8) mucosa but not between the pre- and post-VCMX augmentation time points. The mean BVD in the LM was greater than in the MM (5.5 ± 2.4 and 6.3 ± 2.4 vs. 3.4 ± 3.3 and 3.7 ± 1.8, respectively, p < .05) but not between time points. The collagen fiber arrangements pre- and post-augmentation were not significantly different. CONCLUSION: Augmentation with VCMX did not alter the composition of lining and masticatory mucosa at implant sites. CLINICAL RELEVANCE: A thick soft tissue phenotype around the implant neck is an important factor to maintain peri-implant health. A non-autogenous cross-linking collagen matrix is proposed as an alternate graft substitute in soft tissue augmentation procedures in order to improve implant soft tissue phenotype.

The impact of supportive periodontal treatment on the outcome of regenerative surgical therapy in aggressive periodontitis patients.

Objective: The aim was to evaluate the efficacy of periodontal regenerative therapy using enamel matrix derivatives (EMDs) in aggressive periodontitis patients, and to determine the contribution of maintenance via periodic supportive periodontal treatment. Method and materials: In total, 28 patients were evaluated, comprising 74 intrabony sites. In 50 sites EMD gel was applied, and in 24 sites EMD was combined with deproteinized bovine xenograft. Patients were assigned to a supportive periodontal treatment program; 18 patients fulfilled the program, defined as the well-maintained (WM) group; 10 did not comply, defined as the nonmaintained (NM) group. Probing depth (PD), clinical attachment level (CAL), and radiographic bone level (BL) were recorded. Data were compared presurgically (T0), 6 months postsurgery (T1), and 3 to 10 years posttreatment (T2). Results: Both surgical modalities achieved similar PD reduction, CAL gain, and BL gain, maintained over time. T1 to T2 showed a mean gain/loss of 0.21 ±â€¯0.5 mm and 0.04 ±â€¯1.1 mm, and -0.65 ±â€¯3.0 mm and -0.73 ±â€¯3.0 mm for PD and CAL, respectively, at the WM/NM groups, respectively. BL gain was 21.6% and 11.5% for the WM/NM groups, respectively (P < .05). The courses of the PD, CAL, and BL differed between the WM and NM groups during the observation periods (P < .05). Conclusion: Periodontal regeneration via EMD with/without the combination of deproteinized bovine xenograft can be maintained in aggressive periodontitis cases. It appears that periodic supportive periodontal treatment is a determinant factor in achieving this task.

Monitoring crestal bone level of single- and two-stage implant placement modes up to final prosthetic delivery: an observational study.

OBJECTIVES: To monitor and compare the nonsubmerged (single-stage, SS) and submerged (two-stage, TS) implant placement techniques up to the final prosthesis delivery. Marginal bone level and marginal bone loss rate of both surgical techniques were compared. METHOD AND MATERIALS: Marginal bone level was measured, using an image processing program (ImageJ), from periapical radiographs at the times of placement (T0), exposure (Te), initial loading (T1), and at the final prosthetic delivery (T2), with a total time span of a mean of 13.2 ± 3.3 months. By timing normalization, marginal bone level and marginal bone loss rate (mm/month), following SS and TS implant placement techniques and other local and systemic parameters were analyzed. Asymmetric analyses using Mann-Whitney test followed by the correlation Pearson analyses were applied. A P value < .05 defined statistical significance. RESULTS: In total, 268 implants (42 patients) were monitored. Marginal bone loss rate was 0.15 ± 0.13 mm and 0.13 ± 0.11 mm, between T0 and T2, for the SS and TS techniques, respectively. Marginal bone level and marginal bone loss rate were higher among smokers for both techniques at various time points. Bruxers had higher marginal bone loss rate than nonbruxers between T0 and T1, and T0 and T2. Marginal bone loss rate around implants that were placed at the posterior maxilla was higher than those at the posterior mandible between T1 and T2. Interproximal implant distance correlated negatively with marginal bone loss rate between T0 and T2 (P < .05). CONCLUSIONS: The results suggest that both techniques achieved similar clinical outcome. Smoking, bruxism, anatomical location, and interproximal implant distance apparently affect the marginal bone level and marginal bone loss rate of both implant placement approaches. The implant placement surgical mode, combined with various systemic and/or anatomical factors could play a significant role in maintaining marginal osseous level around the implant neck.

Bone-implant-contact and new bone formation around implants placed in FDB blocks compared to placement at the adjunction of particulate FDB.

BACKGROUND: The efficacy of human freeze-dried bone (h-FDB) as particulate vs block forms as a proper onlay augmented bone graft material to accommodate implants is undetermined. PURPOSE: To evaluate osseointegration and new bone formation at implants placed in FDB blocks (BL group) and those at the adjunction of particulate FDB (PR group). MATERIALS AND METHODS: Twelve pairs of h-FDB blocks were stabilized bilaterally to the calvaria of 12 rabbits. Twenty-four SLA implants were placed at the remodeled grafted blocks, 4 months later. A circumferential gap was created around one implant in each pair and packed with particulate h-FDB. Section biopsies were obtained at 2-month post implant placement (6 months post-block grafting). Bone-to-implant contact (BIC) and bone-area fraction (BAF) were histomorphometrically calculated. RESULTS: The mean BIC was 34.4% and 33.5% for the BL and PR groups, respectively. The mean BAF was 23.9% and 26.4% for the corresponding groups, respectively. Osseointegration and newly formed bone were evident mostly between the threaded portions of the implants in proximity to the host rabbit calvaria compared to its cervical neck. CONCLUSION: The particulate and the cancellous block h-FDB forms yielded similar BIC and BAF outcome. Full revascularization/revitalization is questioned.

Biomaterials and regenerative technologies used in bone regeneration in the craniomaxillofacial region: Consensus report of group 2 of the 15th European Workshop on Periodontology on Bone Regeneration.

BACKGROUND AND AIMS: To review the regenerative technologies used in bone regeneration: bone grafts, barrier membranes, bioactive factors and cell therapies. MATERIAL AND METHODS: Four background review publications served to elaborate this consensus report. RESULTS AND CONCLUSIONS: Biomaterials used as bone grafts must meet specific requirements: biocompatibility, porosity, osteoconductivity, osteoinductivity, surface properties, biodegradability, mechanical properties, angiogenicity, handling and manufacturing processes. Currently used biomaterials have demonstrated advantages and limitations based on the fulfilment of these requirements. Similarly, membranes for guided bone regeneration (GBR) must fulfil specific properties and potential biological mechanisms to improve their clinical applicability. Pre-clinical and clinical studies have evaluated the added effect of bone morphogenetic proteins (mainly BMP-2) and autologous platelet concentrates (APCs) when used as bioactive agents to enhance bone regeneration. Three main approaches using cell therapies to enhance bone regeneration have been evaluated: (a) "minimally manipulated" whole tissue fractions; (b) ex vivo expanded "uncommitted" stem/progenitor cells; and (c) ex vivo expanded "committed" bone-/periosteum-derived cells. Based on the evidence from clinical trials, transplantation of cells, most commonly whole bone marrow aspirates (BMA) or bone marrow aspirate concentrations (BMAC), in combination with biomaterial scaffolds has demonstrated an additional effect in sinus augmentation and horizontal ridge augmentation, and comparable bone regeneration to autogenous bone in alveolar cleft repair.

Regeneration of the Periodontal Apparatus in Aggressive Periodontitis Patients.

The purpose of this study is to evaluate and compare, retrospectively, the outcome of two different periodontal regeneration procedures in patients suffering from aggressive periodontitis (AgP). Twenty-eight patients were diagnosed with AgP, suffering from several intra-bony defects (IBD); that were treated by one of two periodontal regeneration techniques randomly assigned to each patient: a. guided tissue regeneration (GTR) or b. an application of extracted enamel matrix derivatives (EMD) combined with demineralized bone xenograft particles (DBX). Probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession were recorded. Pre-treatment and follow-up (up to 10 years from the surgery) recordings were analyzed statistically within and between groups. A significant reduction was shown at time on PPD and CAL values, however, not between subject groups. CAL values decreased in all sites. At the EMD group (44 sites), CAL gain was 1.92 mm (±1.68) from pre-treatment to follow-up (p < 0.001) and at the GTR group (12 sites) CAL gain of 2.27 (±1.82) mm. In conclusion, 1⁻10 years observations have shown that surgical treatment of AgP patients by either GTR or by application of EMD/DBX results in similar successful clinical results.

Influence of operator skill level on the clinical outcome of non-surgical periodontal treatment: a retrospective study.

OBJECTIVES: The aim of this study is to evaluate the effect of operators experience and skill on treatment results of initial non-surgical periodontal therapy. MATERIALS AND METHODS: Initial periodontal treatment was carried out by either second-year periodontal residents (PR) or last year dental students (DS). From the treatment records of patients in each group, plaque and bleeding indices, and pocket depth (PD) at baseline and at re-evaluation were collected retrospectively on each tooth at six locations. Data were separated according to tooth type, area, and probing depth categories, sub-grouped to 1-3, 4-5, and ≥ 6 mm. RESULTS: Fifty and 49 records of DS and PR patients, accordingly, were analyzed. Initial periodontal treatment improved patient compliance in both groups and reduced signs of inflammation with significantly superior results in the PR group. Significant change in percentage of pockets was recorded in each category. The increase in percentage of sites with PD 1-3 mm and decrease in percentage of PD ≥ 6 mm pockets was significantly (p ≤ 0.001) superior in patients treated by PR. Percentage of 4-5 mm pockets was significantly reduced in both groups (p ≤ 0.01), with a significantly greater reduction in the mandibular molar and anterior teeth in the PR group. CONCLUSIONS: Experience and skill significantly affect the outcome of non-surgical periodontal therapy, with more positive improvement in patient compliance and clinical parameters when performed by a more qualified operator. CLINICAL RELEVANCE: Improvement of operator skills may decrease the number of residual pockets and increase patient compliance following non-surgical periodontal treatment.

Bone-to-Implant Contact and New Bone Formation Within Human Freeze-Dried Bone Blocks Grafted Over Rabbit Calvaria.

PURPOSE: To assess the extent of osseointegration with rough-surface implants and new bone formation (NBF) within human freeze-dried bone blocks (h-FDB) grafted over rabbit calvaria. MATERIALS AND METHODS: A total of 18 rectangular h-FDB blocks were stabilized bilaterally to the calvaria of nine New Zealand rabbits by two mini titanium screws each. A total of 18 rough-surface implants (5.0 × 6.0-mm) were placed, 9 simultaneously (immediate placement [IP]) on one side and 9 at 3 months after block grafting (delayed placement [DP]) on the contralateral side. At 12 weeks after the second surgical procedure, block biopsies were harvested and processed for histologic analysis. Morphometric measurements consisted of bone-to-implant contact (BIC) and the extent of NBF from the calvarial surface and outward into the block. A paired t test was applied for statistical analysis. RESULTS: All h-FDB blocks were integrated, and the implants showed clinical stability. Histologically, the BIC was primarily between the apical end of the implants and the host rabbit calvaria. Bone growth between the implant threads was minimal and inconsistent among all animals. Morphometric measurements showed that the mean BIC of the IP and DP implants with the blocks was 10.50% ± 5.99% and 23.06% ± 9.58%, respectively (P < .001). NBF was observed primarily in the cancellous compartment of the block adjacent to the recipient calvarial bed. The extent of NBF into the block around the IP and DP implants was 9.95% ± 8.41% and 12.90% ± 11.07%, respectively (P = 0.2). CONCLUSION: In this model, a significantly lower BIC was demonstrated when implants were placed simultaneously with h-FDB block grafting compared to those placed in a two-stage mode. However, both techniques showed limited osseointegration.

Deproteinized bovine bone in association with guided tissue regeneration or enamel matrix derivatives procedures in aggressive periodontitis patients: a 1-year retrospective study.

OBJECTIVES: To retrospectively evaluate and compare two regenerative periodontal procedures in young individuals with aggressive periodontitis (AgP). METHODS: Thirty-two patients aged 14-25 years (mean ± SD 19.3 ± 5.7) were diagnosed as having AgP with multiple intra-bony defects (IBDs) and treated by one of two regenerative modalities of periodontal therapy: guided tissue regeneration (GTR) using deproteinized bone xenograft (DBX) particles and a resorbable membrane (the GTR group), or an application of enamel matrix derivatives (EMD) combined with DBX (the EMD/DBX group). Periodic monitoring of treated sites included recording of probing depth (PD), clinical attachment level (CAL) and gingival recession. Pre-treatment and 1-year post-operative findings were statistically analysed within and between groups. RESULTS: The PD and CAL values decreased significantly with time, but not those between study groups. The mean pre-treatment and 1-year post-treatment PDs of the IBDs of the GTR group (n = 16; sites = 67) were 8.93 ± 1.14 mm and 3.58 ± 0.50 mm, respectively, and the mean CALs were 9.03 ± 1.03 mm and 4.16 ± 0.53 mm respectively. The mean PDs of the EMD/DBX group (n = 16; sites = 73) were 8.77 ± 1.04 mm and 3.61 ± 0.36 mm, respectively, and the mean CALS were 8.79 ± 1.04 mm and 3.77 ± 0.22 mm respectively (p < 0.001 for all). CONCLUSION: Surgical treatment of AgP patients by either GTR or by application of EMD/DBX yielded similarly successful clinical results at 1-year post-treatment.

Collagen barrier membranes may accelerate bacterial growth in vitro: a potential clinical risk to regenerative procedures.

OBJECTIVES: Evaluate the antibacterial properties of three commercial collagen membranes for guided bone regeneration (GBR). METHOD AND MATERIALS: BioGide®, OsseoGuard®, and CopiOs® membranes were tested for antibacterial properties against Streptococcus sanguinis, Staphylococcus aureus, and Staphylococcus epidermidis using a direct contact test (DCT). Samples of each membrane, sized 5 × 2 mm, were fixed to the side wall of 6 wells in a 96-well microtiter plate. Bacterial suspension was placed on each sample. The plate was incubated at 37°C for 1 hour to allow suspension fluid evaporation. Fresh medium was added to each well and the plate was mixed. Non-contaminated membrane samples served as negative control. Bacterial growth was monitored spectrophotometrically at 650 nm for 24 hours. ANOVA and Tukey's comparison tests were used for the statistical analysis. RESULTS: The presence of the membrane samples did not disrupt bacterial growth. However, the presence of OsseoGuard membrane accelerated bacterial growth rate of S sanguinis and S epidermidis as compared to the other two membranes and control samples (P < .001), and of S aureus as compared to the control alone (P < .001). CONCLUSIONS: The tested collagen membranes have no antibacterial properties. However, OsseoGuard presents a significant bacterial growth enhancement effect with possible significant clinical implications on the success of regenerative procedures around teeth and implants.

Timing of implant placement and augmentation with bone replacement material: clinical assessment at 8 and 16 months.

PURPOSE: The purpose of this study is to evaluate implants placed at different times of bone augmentation. MATERIALS AND METHODS: Four implants were placed in seven dogs: one at a 6-month bovine mineral grafted site (6-month Bio-Oss® grafted site [6mBio]), one at a grafted membrane-protected simultaneously augmented (Fresh Bio-Oss® grafted site [FrBio]) site, one at a clotted (nongrafted clotted membrane-protected site [Clot]) membrane-protected site, and one at a pristine (nongrafted uncovered site [Cont]) site. Implants were exposed after 6 months. The same protocol was repeated on the contralateral side, at a delay of 8 months. Peri-implant care was performed throughout the hygienic phase (2 and 10 months, respectively) every 48 to 72 hours. Probing depth and bleeding on probing were recorded. Implant stability was determined by a Periotest® (Medizintechnik Gulden, Modautal, Germany). Statistical analysis was conducted using analysis of variance with repeated measures. RESULTS: Average probing depth at the simultaneously grafted sites was 2.21 mm and 2.03 mm at 8 and 16 months, respectively. At the 6-month grafted sites, it was 1.96 mm and 1.57 mm. At the Clot sites, it was 2.68 mm and 2.07 mm, and 2.21 mm and 1.82 mm at the Cont sites, respectively. The average bleeding on probing was 0.50 and 0.42 at the FrBio sites, and 0.35 and 0.07 at the 6mBio sites during the respective periods. At the Clot sites, it was 0.50 and 0.28, and at the Cont sites, 0.43 and 0.21, respectively. Probing depth significantly reduced over the time at 6mBio, Clot, and Cont sites (p < .03). Average implant stability score at the FrBio sites was -0.24 and -0.27, and -0.50 and -0.46 at the 6mBio sites, at 8 and 16 months, respectively. At the Clot sites, it was -0.35 and -0.46. Cont sites averaged -0.37 at both periods. Implant stability was significantly higher (p < .005) comparing 6mBio over FrBio, 6mBio over Cont, and Clot over FrBio sites. CONCLUSIONS: Immediate and delayed augmentations are safe modes. Probing depth and bleeding indices gradually improved along time. Implant stability was higher at the delayed mode.

Socket site preservation using bovine bone mineral with and without a bioresorbable collagen membrane.

The purpose of this study was to compare extraction sites augmented with bovine bone mineral (BBM) with and without resorbable membrane coverage. BBM particles were grafted in fresh human extraction sockets of 23 patients; in 12 of these patients, a guided tissue regeneration (GTR) membrane was applied. After 9 months of histomorphometric evaluation, cylindric hard tissue specimens were obtained. Percent bone area fractions (BAFs) of the crestal, middle, and apical sections from each specimen were calculated using the point-counting technique. Changes in values were compared. In sites augmented with BBM, the mean BAF ranged from 22.8% (coronal) to 36.3% (apical) compared to sites augmented with BBM and collagen membrane (35.2% [coronal] to 47% [apical]). Comparison between the different depths and the two groups showed a distinct increase in BAF from coronal to apical regions (P < .001). This pattern was observed in both groups (P < .001) and was significantly higher in the group augmented with BBM and collagen membrane (P < .05). In the immediate postextraction phase, BBM as a grafted biomaterial preserved the socket volume and enabled newly formed bone for future implant site preparation. The amount of the osseous fraction increased with GTR membrane.

Effect of guided tissue regeneration on newly formed bone and cementum in periapical tissue healing after endodontic surgery: an in vivo study in the cat.

INTRODUCTION: The purpose of this study was to evaluate the influence of anorganic bovine bone as a grafted biomaterial on newly formed bone and cementum in periapical regions after surgical endodontic treatment in cats. METHODS: After inducing apical periodontitis in 9 cats, root canal and surgical endodontic treatment were performed on 72 roots of first and second maxillary premolars. Bone defects were treated with biomaterial particles + a membrane, biomaterial only, a membrane only, or left unfilled (control). Histomorphometry on nondecalcified sections were performed at 3 and 6 months after surgery. Analysis of variance with repeated measures was used within 2 and 3 subject factors to analyze newly formed bone, cementum, biomaterial conduction, and resorption. RESULTS: At each time period, bone formation was greater at the grafted membrane-protected sites than in the grafted-unprotected sites. At 6 months, the bone area fraction at membrane nongrafted sites was greater than in the grafted-protected sites. The new cementum was significantly greater at 6 months than at 3 months and greater at the grafted membrane-protected sites over the unprotected ones at 6 months. Statistically, the grafted biomaterial, the membrane, and the time contributed significantly to the amount of new bone (P<.05) with no significant interaction. Biomaterial osteoconduction was significantly affected by the time. All 3 variables showed a significant interaction on new cementum. CONCLUSIONS: There was significantly more bone formation after surgical endodontic treatment when membrane and bone grafts were used as compared with bone grafts only or unfilled control sites. However, it appears that the key factor to the enhanced tissue regeneration is the membrane and not the grafted biomaterial.