Guided bone regeneration at dehiscence comparing synthetic bone substitute versus bovine bone mineral: A multicenter, noninferiority, randomized trial.

AIM: To evaluate the efficacy of guided bone regeneration (GBR) for the treatment of peri-implant dehiscence defects using a synthetic bone substitute (SBS) or a deproteinized bovine bone mineral (DBBM) as a bone substitute. METHODS: Patients with expected dehiscence defects following implant placement were randomized to use either SBS or DBBM together with a bioabsorbable collagen membrane over dehiscenced implant surfaces aimed for GBR. The changes in the bone defect size were measured before the GBR procedure and 6 months after implant placement at the re-entry surgery. Secondary outcomes included peri-implant health outcomes, implant cumulative survival rates, bone level changes, and patient-reported outcomes (PROMs) at prosthesis delivery and 1-year follow-up. RESULTS: Of the 49 included patients, 24 were treated with SBS and 25 with DBBM. In the SBS group, the defect height (DH) at implant insertion was 5.1 ± 2.6 mm and was reduced at re-entry to 1.3 ± 2.0 mm (74.5%). In the DBBM group, the respective changes in DH were 4.1 ± 1.7 mm and 1.5 ± 1.9 mm (63.4%). These differences were not statistically significant (p = 0.216). The complete defect resolution rate was also comparable in both groups without statistical difference (62.5% of patients (15/24) vs. 44% of patients (11/25)). Overall, the marginal bone levels remained stable during the 1-year follow-up in both groups. CONCLUSION: The SBS is noninferior to DBBM for simultaneous GBR to implant placement at implant sites with buccal dehiscences in terms of defect resolution and evaluated secondary outcomes (KCT0008393 - this clinical trial was not registered before participant recruitment and randomization).

Local delivery of pamidronate with collagen matrix mitigates buccal bone resorption following immediate implant placement - An experimental in vivo study.

AIMS: The aim of this experimental in vivo pilot study was to evaluate the effect of the local delivery of pamidronate within a collagen membrane on the changes in the buccal soft and hard tissue dimensions at the time of immediate implant placement and whether this effect was influenced by the placement of bone substitutes. METHODS: In six beagle dogs, the distal roots of the third and fourth premolars were extracted, and immediate implants were placed. Treatment groups were randomly allocated to each socket: (i) covering the buccal bone with pamidronate-soaked collagen membrane (BP group), (ii) filling the gap defect with synthetic bone substitute (BS group), (iii) filling the gap defect with synthetic bone substitute and covering the buccal bone with pamidronate soaked collagen membrane (BP/BS group), (iv) no treatment (control group). Intraoral scanning was performed immediately after the surgery and at 20 weeks. Histomorphometric and micro-computed tomography (CT) outcomes were evaluated at 20 weeks. RESULTS: The micro CT analysis demonstrated that the BP group showed no apparent difference in vertical bone level with residual mesial root area, while control group showed significant buccal bone resorption at the implant site. The histomorphometric analysis demonstrated that the vertical bone level of buccal plate was significantly differed between the BP and control group (0.34 ± 0.93 and 1.27 ± 0.56 mm, respectively; p = .041). There was no statistically significant difference in the horizontal ridge width (HRW 1, 2, 3) among the groups. Also, the thickness, height and buccal contours of the soft tissue did not reveal significant changes among the groups. CONCLUSION: The local delivery of pamidronate to the outer surface of the buccal wall at the time of immediate implant placement effectively limits buccal bone resorption. The results from the present investigation should be interpreted with caution, as well as its clinical translatability. Further investigation is needed to understand the pamidronate binding and releasing kinetic, as well as the ideal carrier of this drug for its topical application.

Randomized controlled trial on the efficacy of a custom-made, fully guided implant system for flapless crestal sinus floor elevation: Accuracy and patient-reported outcomes.

OBJECTIVE: To compare fully guided flapless implant surgery using a light-cured surgical guide (FG group) with partially guided open flap surgery (PG group) in the posterior maxilla when performing simultaneous sinus floor elevation in terms of the accuracy, time requirements, and patient/clinician-reported outcomes (PROMs and CROMs). MATERIALS AND METHODS: In this study, 56 tissue-level implants were placed with crestal sinus floor elevation in 56 patients at single-tooth sites, with 28 implants allocated to the PG group and 28 to the FG group. The deviations of the placed implants from the virtually planned positions were measured at the implant platform and apex and for the angular deviation. The presurgical preparation time and the duration of surgery were measured. PROMs and CROMs were made by administering questionnaires at multiple time points. RESULTS: Horizontal deviations at the platform and apex and the angular deviation were significantly smaller in the FG group than the PG group (p < .05). Presurgical preparation and surgery times were significantly shorter in the FG group (p < .001). Patient satisfaction and willingness to receive repeat treatment were significantly better in the FG group than in the PG group (p < .005 and .025, respectively). Clinicians were more satisfied in the FG group than the PG group (p < .05). CONCLUSION: When placing an implant with sinus floor elevation, the flapless approach using a fully guided surgical system can be more accurate, faster, and increase the satisfaction of both the clinician and patient compared to the partially guided surgery.

Synchrotron Analysis of Damaged Extraction Sockets Augmented Using a Synthetic Bone Block: A Pilot Study.

This study aimed to investigate the dimensional stability and quality of the alveolar ridge augmented using a synthetic bone block (SBB) at damaged extraction sockets. Four participants were included, and socket augmentation was performed using SBB and a collagen membrane. Intraoral and CBCT scans were performed before extraction (baseline), immediately postoperative (IP), and at 6 months postoperative (6M). At 6M, a trephine biopsy sample was obtained during implant placement, and the sample was observed using synchrotron. Soft tissue profile changes were assessed using profilometric analysis of the intraoral scan data, while dimensional changes in hard tissue were evaluated based on CBCT measurements. Bone quality was analyzed using synchrotron imaging. There were minimal changes in the soft tissue profile between baseline and IP, baseline and 6M, and IP and 6M (0.11 ± 1.08 mm3, 0.02 ± 0.8 mm3, and -0.65 ± 0.82 mm3, respectively). Horizontal bone width was measured at 1-mm increments from the augmented bone crest to 5 mm apically and revealed only a slight reduction (< 1 mm) at all levels between IP and 6M. The augmented bone height was well maintained from IP until 6M (-0.21 ± 0.53 mm). Synchrotron analysis revealed low to moderate bone quality after 6M (percentage of new bone: 16.49% ± 4.91%). Socket augmentation using SBB appears to be a viable technique for regenerating damaged extraction sockets, with the augmented ridge dimensions maintained up to 6M. Further long-term randomized clinical trials are needed.

Risk of post-operative bleeding after dentoalveolar surgery in patients taking anticoagulants: a cohort study using the common data model.

This retrospective study aimed to determine risk factors associated with post-operative bleeding after dentoalveolar surgery in patients taking anticoagulants. Patients taking anticoagulants who were planned to undergo periodontal flap operation, tooth extraction or implant surgery were included. Patients were divided into two subgroups according to the maintenance of anticoagulants following medical consultation: (1) maintenance group and (2) discontinuation group. The analysed patient-related factors included systemic diseases, maintenance of anticoagulants and types of anticoagulant. Intra- and post-operative treatment-related factors, haemostatic methods and post-operative bleeding were collected for statistical analyses. There were 35 post-operative bleeding complications (6.5%) in the 537 included patients: 21 (8.6%) in maintenance group and 14 (4.8%) in discontinuation group. The type of anticoagulant (p = 0.037), tooth extraction combined with bone grafting (p = 0.016) and type of implant surgery (p = 0.032) were significantly related to the post-operative bleeding rate. In the maintenance group, atrial fibrillation [odds ratio (OR) = 6.051] and vitamin K inhibitors (OR = 3.679) were associated with a significantly higher bleeding risk. From this result, it can be inferred that the decision to continue anticoagulants should be made carefully based on the types of anticoagulant and the characteristics of dentoalveolar surgeries performed: extraction with bone grafting, multiple implantations and involvement of maxillary arch.

Effects of a modified surgical protocol on the positional accuracy of dental implants placed using fully guided implant surgery in the partially edentulous posterior ridge with distal extension: a dentiform model study.

PURPOSE: The present experiment aimed to evaluate the placement accuracy of fully guided implant surgery using a mucosa-supported surgical guide when the protocol of osteotomy and installation was modified (MP) compared to when the protocol was sequentially and conventionally carried out (CP). MATERIALS AND METHODS: For 24 mandibular dentiform models, 12 dentists (6 experts and 6 beginners) performed fully guided implant placements two times at the right first and second molar sites using a mucosa-supported surgical guide, once by the CP (CP group) and at the other time by the MP (MP group). The presurgical and postsurgical stereolithographic images were superimposed, and the deviations between the virtually planned and actually placed implant positions and the procedure time were compared statistically (P < .05). RESULTS: The accuracies were similar in the CP and MP groups. In the CP group, the mean platform and apex deviations at the second molar site for the beginners were +0.75 mm and +1.14 mm, respectively, which were significantly larger than those for the experts (P < .05). In the MP group, only the mean vertical deviation at the second molar site for the beginners (+0.53 mm) was significantly larger than that for the experts (P < .05). The procedure time was significantly longer for the MP group (+94.0 sec) than for the CP group (P < .05). CONCLUSION: In fully guided implant surgery using a mucosa-supported guide, the MP may improve the placement accuracy when compared to the CP, especially at sites farther from the most-posterior natural tooth.

Flapless early implant placement into the uncalcified provisional matrix-Does it lead to osseointegration of the implant? A preclinical study.

AIM: To test whether early implant placement into the extraction socket containing an uncalcified provisional matrix leads to successful osseointegration and stable marginal bone levels. MATERIALS AND METHODS: In six mongrel dogs, the mandibular molars were extracted. Three weeks later, early implant placement was performed according to three experimental protocols: (i) flapless implant placement with preservation of the provisional matrix; (ii) flap elevation, socket debridement and implant placement; and (iii) flap elevation, socket debridement, implant placement and guided bone regeneration (GBR). One untreated extraction socket served as a control group. Data analyses were based on histologic slides 3 months after implant placement. RESULTS: There were no differences in bone-to-implant contact between the three experimental groups (66.97%, 58.89% and 60.89%, respectively) (inter-group comparison p = .42). Marginal bone levels, first bone-to-implant contact as well as the thickness of the connective tissue did not reveal any significant differences between the groups (p = .85, .60 and .65, respectively). CONCLUSIONS: Flapless early implant placement into posterior extraction sockets was as effective as an open flap approach in conjunction with GBR. Mineralization of the socket seems to occur irrespective of the presence of dental implants or biomaterials.

Ridge preservation using a self-retaining block type bone substitute for extraction sockets with buccal dehiscence defects - A preclinical study.

OBJECTIVE: To evaluate the effect of a self-retaining block-type bone substitute (srBB) on the dimensional stability of the horizontal ridge width at the coronal level in a buccal dehiscence model. MATERIALS AND METHODS: Four box-shaped bone defects with a buccal dehiscence were surgically prepared in the partially edentulous mandible (n = 6). Experimental biomaterials were randomly assigned to each site: (1) Control group: no treatment, (2) particle-type bone substitute (PBS) group, (3) collagenated soft block bone substitute (csBB) group, and (4) self-retaining synthetic block bone (srBB) group. In all grafted groups, a collagen membrane covered the biomaterials. At 16 weeks, clinical, histological, and radiographic analyses were performed. RESULTS: Three of the six blocks in the srBB group became exposed and fell out during the first week after surgery. Therefore, the remaining three specimens were renamed RsrBB group. The RsrBB group showed an increase horizontal ridge compared to the pristine bone width at 2-4 mm below the CEJ, while the other groups showed resorption (augmented width at 2 mm below: 4.2, 42.4, 36.2, and 110.1% in the control, PBS, csBB, and RsrBB groups, respectively). The mineralized bone area was largest in the RsrBB group (4.74, 3.44, 5.67, and 7.77 mm2 in the control, PBS, csBB, and RsrBB groups, respectively.). CONCLUSIONS: The srBB group demonstrated the highest volume stability at the coronal level. These findings would potentially suggest that self-retaining block bone substitute might be a good candidate for alveolar ridge preservation.

Host modulation therapy for improving the osseointegration of dental implants under bone healing-suppressed conditions: a preclinical rodent-model experiment.

PURPOSE: Placing dental implants in areas with low bone density or in conditions where bone healing is suppressed is challenging for clinicians. An experiment using a rodent model was performed with the aim of determining the efficacy of host modulation by increasing the systemic level of cholesterol sulfate (CS) using Irosustat in the context of the bone healing process around dental implants. METHODS: In 16 ovariectomised female Sprague-Dawley rats, 2 implant fixtures were placed in the tibial bones (1 fixture on each side). At 1 week after surgery, the high-CS group (n=8) received Irosustat-mixed feed, while the control group (n=8) was fed conventionally. Block specimens were obtained at 5 weeks post-surgery for histologic analysis and the data were evaluated statistically (P<0.05). RESULTS: Unlike the high-CS group, half of the specimens in the control group demonstrated severe bone resorption along with a periosteal reaction in the cortex. The mean percentages of bone-to-implant contact (21.5%) and bone density (28.1%) near the implant surface were significantly higher in the high-CS group than in the control group (P<0.05), as was the number of Haversian canals (by 5.3). CONCLUSIONS: Host modulation by increasing the CS level may enhance the osseointegration of dental implants placed under conditions of impaired bone healing.

Synchrotron Analysis of Damaged Extraction Sockets Augmented Using a Synthetic Bone Block: A Pilot Study.

AIM: To investigate the dimensional stability and quality of the alveolar ridge augmented using a synthetic bone block (SBB) at damaged extraction sockets. MATERIALS AND METHODS: Four participants were included in whom socket augmentation was performed using SBB and a collagen membrane. Intraoral scan (IOS) was performed before extraction (baseline), immediately postoperative (IP), and at 6 months (6M). Cone-beam computed tomography (CBCT) was performed at IP and 6M. At 6M, a trephine biopsy was obtained during implant placement and the sample was observed using synchrotron. Profilometric change of soft tissue was measured from the IOS data, hard tissue dimensional change was measured from the CBCT data and the bone quality from synchrotron data. RESULTS: There were minimal changes in the soft tissue profile between baseline and IP, baseline and 6M, and IP and 6M (0.11±1.08 and 0.02±0.8, and -0.65±0.82 mm3). Horizontal bone width measured at 1 mm increments from the augmented bone crest to 5 mm apically revealed only slight reduction (less than 1 mm) at all levels between IP and 6M. The augmented bone height was well maintained from IP until 6M (-0.21±0.53 mm). Synchrotron analysis revealed low to moderate bone quality after 6M (percentage new bone = 16.49±4.91). CONCLUSIONS: Augmentation of the damaged extraction socket using SBB is a viable technique, in which the dimensions of the augmented ridge can be maintained up to 6M. Further long term randomized clinical trial is needed.

Soft-tissue dimensional change following guided bone regeneration on peri-implant defects using soft-type block or particulate bone substitutes: 1-year outcomes of a randomized controlled clinical trial.

AIM: To compare the peri-implant soft-tissue dimensional changes following guided bone regeneration between particulate (particle group) and collagenated soft-block-type (block group) biphasic calcium phosphate (BCP). MATERIALS AND METHODS: This study investigated 35 subjects: 18 in the particle group and 17 in the block group. Cone-beam computed tomography obtained at 6 months post surgery and optical impressions taken periodically (before surgery, 6 months post surgery, and 1 year post surgery) were superimposed. The ridge contour changes over time and the peri-implant mucosal thicknesses were measured diagonally and horizontally, and analysed statistically. RESULTS: The increases in diagonal (1.12 ± 0.78 mm) and horizontal (2.79 ± 1.90 mm) ridge contour of the block group were significantly higher than those in the particle group during the first 6 months (p < .05); however, the contour hardly changed thereafter (diagonal: 0.07 ± 0.75 mm; horizontal: -0.34 ± 1.26 mm), resulting in the 1-year contour changes similar between the two groups. Regardless of the type of BCP, the ridge contour increased significantly over 1 year when the dehiscence defect had a contained configuration (p < .05). CONCLUSIONS: The increase in soft-tissue dimensions for 1 year was similar between the two groups. The mucosal contour increase was larger when the surgery was conducted in a more contained defect, and this was not influenced by the type of BCP.

Immediate loading of fixed partial prostheses reconstructed using either tapered or straight implants in the posterior area: A randomized clinical trial.

BACKGROUND: In immediately loaded implants within 72 h after the implant placement in the unilaterally and partially edentulous ridge, primary stability is considered critical, which can be influenced by the design of the implant fixture. PURPOSE: To determine the outcomes at 1 year after the immediate loading of multiunit fixed partial prostheses over either tapered implants (TIs) or straight implants (SIs) in the posterior region. MATERIALS AND METHODS: Forty-eight patients (24 patients, 52 implants in TI group; 24 patients, 50 implants in SI group) were included for the study. Except for the one SI group patient whose two implants showed the insertion torque less than 30 Ncm, provisional prostheses designed and fabricated from intraoral scan data obtained immediately after implant surgery were delivered to rest of the 47 subjects at 3-7 days. After a year, the survival rate was estimated by intention-to-treat (ITT) and per-protocol (PP) analyses, and marginal bone loss (MBL) and implant stability were also analyzed statistically (p < 0.05). RESULTS: Survival rate at implant level in TI group was 96.2%, and that of SI group in the ITT analysis was 86.0%. Intergroup difference, however, was not statistically significant (p > 0.05). Insertion torque was significantly higher in TI group than SI group (47.12 ± 6.37 Ncm vs. 41.60 ± 9.77 Ncm; p < 0.05). MBLs of both groups were less than 0.1 mm at 1-year follow-up and was similar between two groups (p > 0.05). CONCLUSIONS: Immediate loading of fixed partial prostheses after TI and SI placement showed reliable outcomes in the partially edentulous posterior ridge. In terms of the initial mechanical stability, the performance was superior for TIs than for SIs.

Addition of autogenous bone chips to deproteinized bovine bone mineral does not have additional benefit in lateral ridge augmentation-A preclinical in vivo experimental study.

OBJECTIVE: To compare the outcome after extensive lateral guided bone regeneration using deproteinized bovine bone mineral (DBBM) with or without autogenous bone chips in a canine model of chronic horizontal alveolar ridge defect. MATERIALS AND METHODS: The second, third and fourth lower premolars of both sides were extracted, and the buccal bone walls were completely removed in five beagle dogs. After 4 weeks, DBBM particles mixed with autogenous bone chips at a ratio of 1:1 were grafted at one side (DBBM/Auto group), while DBBM particles alone were grafted at the contralateral side (DBBM group). The graft materials on both sides were covered by a resorbable collagen membrane and fixation pins. Microcomputed tomographic volume and histomorphometric analyses were performed at 16 weeks post-surgery. RESULTS: The ridges of both groups were recovered horizontally, but new bone formation beyond the original ridge contour at the defect site was not found. The DBBM group exhibited a larger total radiographic augmented volume and new bone volume compared with the DBBM/Auto group, but the differences were minimal (p > .05). Histologically, the regenerated area and new bone area were also slightly larger without any statistical significance in the DBBM group than in the DBBM/Auto group (p > .05). CONCLUSION: The addition of autogenous bone chips to DBBM for lateral ridge augmentation may confer no advantage over grafting DBBM alone with respect to both space maintenance and de novo bone formation in dogs.

Accuracy of Dental Implant Placement by a Novel In-House Model-Free and Zero-Setup Fully Guided Surgical Template Made of a Light-Cured Composite Resin (VARO Guide®): A Comparative In Vitro Study.

BACKGROUND: This in vitro study mainly aimed to compare VARO Guide® to the surgical guide fabricated by CAD/CAM (NAVI Guide®) in terms of accuracy and efficacy of the implant surgery held in the dentiform model. METHODS: Twenty surgeons, 10 dentists in the beginner group and 10 dentists in the expert group, participated in the study. Each surgeon conducted fully guided surgery in dentiform models twice, once with VARO Guide® (VG surgery) and the other time with a conventional type of templates, NAVI Guide® (NG surgery). Based on the superimposition of presurgical and postsurgical STL files, the positional deviations between the virtually planned and actually placed implants and the time spent on presurgical preparation and surgical procedures were estimated and compared. RESULTS: All dimensional deviations were similar between the two groups (p > 0.05), and there was no significant difference between the expert and beginner groups regardless of the guide system. The total procedure time (mean (median)) of the VG surgery (26.33 (28.58) min) was significantly shorter than that of the NG surgery (378.83 (379.35) min; p < 0.05). While the time spent only for the fully guided implant surgery (from the start of the surgical guide sitting onto the dentiform model to the final installation of the implant fixture) was comparable (p > 0.05), the presurgical preparation time spent on virtual implant planning and surgical guide fabrication in the VG surgery (19.63 (20.93) min) was significantly shorter compared to the NG surgery (372.93 (372.95) min; p < 0.05). CONCLUSIONS: Regardless of experience, both VG and NG surgery showed reliable positional accuracy; however, the total procedure time and the preparation time were much shorter in the VG surgery compared to the NG surgery.

Intranuclear Delivery of Nuclear Factor-Kappa B p65 in a Rat Model of Tooth Replantation.

After avulsion and replantation, teeth are at risk of bone and root resorption. The present study aimed to demonstrate that the intra-nuclear transducible form of transcription modulation domain of p65 (nt-p65-TMD) can suppress osteoclast differentiation in vitro, and reduce bone resorption in a rat model of tooth replantation. Cell viability and nitric oxide release were evaluated in RAW264.7 cells using CCK-8 assay and Griess reaction kit. Osteoclast differentiation was evaluated using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and tartrate-resistant acid phosphatase (TRAP) staining. Thirty-two maxillary rat molars were extracted and stored in saline (n = 10) or 10 µM nt-p65-TMD solution (n = 22) before replantation. After 4 weeks, specimens were scored according to the inflammatory pattern using micro-computed tomography (CT) imaging and histological analyses. nt-p65-TMD treatment resulted in significant reduction of nitric oxide release and osteoclast differentiation as studied using PCR and TRAP staining. Further, micro-CT analysis revealed a significant decrease in bone resorption in the nt-p65-TMD treatment group (p < 0.05). Histological analysis of nt-p65-TMD treatment group showed that not only bone and root resorption, but also inflammation of the periodontal ligament and epithelial insertion was significantly reduced. These findings suggest that nt-p65-TMD has the unique capabilities of regulating bone remodeling after tooth replantation.

Immunohistochemical characteristics of lateral bone augmentation using different biomaterials around chronic peri-implant dehiscence defects: An experimental in vivo study.

AIM: To investigate the immunohistochemical characteristics of a highly porous synthetic bone substitute and a cross-linked collagen membrane for guided bone regeneration. METHODS: Three experimental groups were randomly allocated at chronic peri-implant dehiscence defect in 8 beagle dogs: (i) biphasic calcium phosphate covered by a cross-linked collagen membrane (test group), (ii) deproteinized bovine bone mineral covered by a natural collagen membrane (positive control) and (iii) no treatment (negative control). After 8 and 16 weeks of submerged healing, dissected tissue blocks were processed for immunohistochemical analysis. Seven antibodies were used to detect the remaining osteogenic and angiogenic potential, and quantitative immunohistochemical analysis was done by software. RESULTS: The antigen reactivity of alkaline phosphatase was significantly higher in the test group compared to the positive and negative controls, and it maintained till 16 weeks. The intensity of osteocalcin was significantly higher in the positive control at 8 weeks than the other groups, but significantly decreased at 16 weeks and no difference was found between the groups. A significant large number of TRAP-positive cells were observed in the test group mainly around the remaining particles at 16 weeks. The angiogenic potential was comparable between the groups showing no difference in the expression of transglutaminase II and vascular endothelial growth factor. CONCLUSION: Guided bone regeneration combining a highly porous biphasic calcium phosphate synthetic biomaterial with a crosslinked collagen membrane, resulted in extended osteogenic potential when compared to the combination of deproteinized bovine bone mineral and a native collagen membrane.

Immediate versus delayed application of bone morphogenetic protein-2 solution in damaged extraction sockets: a preclinical in vivo investigation.

OBJECTIVE: To compare the clinical, radiographic, and histological healing patterns between the immediate and delayed applications of bone morphogenetic protein-2 (BMP-2) in damaged extraction sockets in dogs. MATERIALS AND METHODS: The distal roots of the fourth premolars of the mandible were extracted bilaterally in five beagle dogs, and buccal bone defects (4 mm wide and 9 mm high) were surgically created. Collagenated biphasic calcium phosphate (CBCP) soaked for 10 min in 100 µL of BMP-2 solution was applied immediately to the defect site in the control group. In the test group, the BMP-2 solution of same dose was injected into the grafted site 2 weeks after grafting with a saline-soaked CBCP. The dogs were sacrificed 2 weeks later. Clinical, histological, and radiographic analyses were followed. RESULTS: Swelling and inflammatory reactions were predominantly observed in the control group at 2 weeks. The area of new bone formation was significantly larger in the control group compared with the test group (10.8 ± 7.0 mm2 [mean ± SD] and 6.3 ± 3.1 mm2, respectively; p = 0.043). No significant difference was found in ridge width at 2 mm, 4 mm and 6 mm below the lingual bone crest between the control (2.6 ± 1.0 mm, 3.2 ± 0.9 mm and 4.5 ± 0.5 mm, respectively) and test group (3.3 ± 1.0 mm, 3.7 ± 1.3 mm and 4.2 ± 1.0 mm; all p > 0.05). CONCLUSIONS: Delayed application of BMP-2 2 weeks after surgery did not show any advantage over immediate application of BMP-2 in terms of new bone formation. CLINICAL RELEVANCE: This study suggests that it might be better to apply BMP-2 immediately in alveolar ridge preservation, instead of delayed application, in order to enhance new bone formation.

Dimensional changes of the maxillary sinus augmented with a collagenated synthetic bone block or synthetic bone particulates: A pre-clinical study in rabbits.

OBJECTIVE: To compare the efficacy of a collagenated synthetic bone substitute (C-SBS) to a particulated synthetic bone substitute (P-SBS) in volume maintenance and new bone formations in a rabbit sinus model. MATERIALS AND METHODS: Either C-SBS or P-SBS was grafted in both sinuses of 16 rabbits. Four (N = 8) or 12 (N = 8) weeks after the surgery, total augmented volume (TAV) and area (TAA), as well as new bone volume (NBV) and area (NBA), were statistically compared by radiographic and histomorphometric analyses (p < .05). RESULTS: The differences in TAV, NBV, TAA and NBA between C-SBS and P-SBS groups at 4 weeks were not statistically significant. The TAV (267.13 ± 62.08 vs. 200.18 ± 40.32 mm3 ) and NBV (103.26 ± 10.50 vs. 71.10 ± 7.58 mm3 ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05). The TAA (19.36 ± 2.88 vs. 14.48 ± 2.08 mm2 ) and NBA (5.43 ± 1.20 vs. 3.76 ± 0.78 mm2 ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05). CONCLUSIONS: Collagenated synthetic bone substitute grafted in rabbit sinuses demonstrated more favourable outcomes across all outcome measures compared to P-SBS at 12 weeks.

Effects of soft tissue grafting prior to orthodontic treatment on preventing gingival recession in dogs.

PURPOSE: This study was conducted to assess the efficacy of prophylactic gingival grafting in the mandibular anterior labial area for preventing orthodontically induced gingival recession. METHODS: Eight mongrel dogs received gingival graft surgery at the first (I1) and third (I3) mandibular incisors on both sides based on the following group allocation: AT group (autogenous connective tissue graft on I1), AT-control group (contralateral side in the AT group), CM group (xenogeneic cross-linked collagen matrix graft on I3) and CM-control group (contralateral side in the CM group). At 4 weeks after surgery, 6 incisors were splinted and proclined for 4 weeks, followed by 16 weeks of retention. At 24 weeks after surgery, casts were made and compared with those made before surgery, and radiographic and histomorphometric analyses were performed. RESULTS: Despite the proclination of the incisal tip (by approximately 3 mm), labial gingival recession did not occur. The labial gingiva was thicker in the AT group (1.85±0.50 mm vs. 1.76±0.45 mm, P>0.05) and CM group (1.90±0.33 mm vs. 1.79±0.20 mm, P>0.05) than in their respective control groups. CONCLUSIONS: The level of the labial gingival margin did not change following labial proclination of incisors in dogs. Both the AT and CM groups showed enhanced gingival thickness.

Locally Applied Slow-Release of Minocycline Microspheres in the Treatment of Peri-Implant Mucositis: An Experimental In Vivo Study.

BACKGROUND: The objective of this is preclinical investigation was to evaluate the differential drug sustainability and pharmacodynamic properties of two local minocycline microsphere carriers: chitosan-coated alginate (CA) and poly(meth)acrylate-glycerin (PG). METHODS: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Each implant was randomly assigned to receive one of the following four treatments: (i) CA (CA-based minocycline), (ii) placebo (CA substrate without minocycline), (iii) PG (PG-based minocycline) and (iv) control (mechanical debridement only). After inducing peri-implant mucositis, the randomly assigned treatments were administered into the gingival sulcus twice at a 4-week interval using a plastic-tipped syringe. Drug sustainability and pharmacodynamic (clinical, radiographical and cell marker intensity) evaluations were performed after each administration. RESULTS: The CA microspheres remained longer around the healing abutment compared to the PG microspheres at both administrations and a longer bacteriostatic effect was observed from CA (7.0 ± 5.7 days) compared to PG (1.2 ± 2.6 days). The efficacy of the applied therapies based on clinical, radiographical and histological analyses were comparable across all treatment groups. CONCLUSIONS: CA microspheres showed longer carrier and bacteriostatic effect sustainability when compared to PG microspheres, however, longer drug sustainability did not lead to improved treatment outcomes.