Boron- and Boric Acid-Treated Titanium Implant Surfaces in Sheep Tibia: A Histologic, Histomorphometric and Mechanical Study.

The aim of this study was to compare the topographical, chemical and osseointegration characteristics of sandblasting and acid-etching (SLA) surfaces and dental implants treated by boron compounds. Titanium (Ti) disks (n = 20) were modified using boron (B) and boric acid (H3BO3) and then compared with the conventional SLA surface via surface topographic characterizations. Dental implants (3.5 mm in diameter and 8 mm in length) with the experimental surfaces (n = 96) were inserted into the tibias of six sheep, which were left to heal for 3 and 7 weeks. Histologic, histomorphometric (bone−implant contact (BIC%)) and mechanical tests (removal torque value (RTV)) were performed. The boron-coated surface (BC group) was smoother (Rz: 4.51 µm ± 0.13) than the SLA (5.86 µm ± 0.80) and the SLA-B (5.75 µm ± 0.64) groups (p = 0.033). After 3 weeks, the highest mean RTV was found in the SLA group (37 N/cm ± 2.87), and the difference compared with the BC group (30 N/cm ± 2.60) was statistically significant (p = 0.004). After 7 weeks, the mean RTV was >80 N/cm in all groups; the highest was measured in the H3BO3-treated (BS) group (89 N/cm ± 1.53) (p < 0.0001). No statistically significant differences were found in the BIC%s during both healing periods between the groups. H3BO3 seems to be a promising medium for dental implant osseointegration.

May Autogenous Grafts Increase the Effectiveness of Hyalonect Membranes in Intraosseous Defects: An Experimental In Vivo Study.

Background and Objectives: Guided bone regeneration (GBR) surgeries are used for dental implant placements with insufficient bone volume. Biomaterials used in GBR are expected to produce sufficient volume and quality of bone swiftly. This study aims to histologically evaluate the effectiveness of the use of Hyalonect membranes alone or with autogenous grafts in intraosseous defects. Materials and Methods: This study is an experimental study on sheep. Surgeries were performed under general anesthesia in accordance with ethical rules. Five 10 mm defects were surgically created in each ilium of six sheep. One defect was left empty in each ilium (group ED). The defects in the experimental group were covered with Hyalonect membrane while unfilled (group HY) or after being filled with autogenous bone grafts (ABG) (group G+HY). In the control group, the defects were either covered with collagen membrane while unfilled (group CM) or after being filled with the ABG group (G+CM). The sheep were histologically and histomorphometrically evaluated after being postoperatively sacrificed in the third and sixth week (three animals in each interval). Results: All animals completed the study without any complications. No difference was found between groups in the third and sixth weeks regarding the inflammation, necrosis, and fibrosis scores. The G+CM (52.83 ± 3.06) group was observed to have a significantly higher new bone formation rate than all the other groups in the third week, followed by the G+HY group (46.33 ± 2.25). Similar values were found for HY and CM groups (35.67 ± 4.55 ve 40.00 ± 3.41, respectively, p = 0.185), while the lowest values were observed to be in group ED (19.67 ± 2.73). The highest new bone formation was observed in group G+CM (82.33 ± 4.08) in the sixth week. There was no difference in new bone formation rates between groups G+CM, G+HY (77.17 ± 3.49, p = 0.206), and CM (76.50 ± 2.43, p = 0.118). The insignificant difference was found ED group and group HY (55.83 ± 4.92, 73.50 ± 3.27, respectively, p = 0.09). The residual graft amount in the G+CM group was found to be statistically significant at 3 weeks (p = 0.0001), compared to the G+HY group, and insignificantly higher at the 6th week (p = 0.4). Conclusions: In this study, close values were observed between G+HY and G+CM groups. Further experimental and clinical studies with different graft materials are required to evaluate the effectiveness of HY in GBR.

Effects of Platelet-Rich Fibrin on Hard Tissue Healing: A Histomorphometric Crossover Trial in Sheep.

Bone defects lead to aesthetic and functional losses, causing dental rehabilitation to be more difficult. The objective of this work is to histologically assess the hard tissue healing of bone defects filled with platelet-rich fibrin (PRF) alone or as an adjuvant for mixing with and covering anorganic bovine bone (ABB), compared to ABB covered with a resorbable collagen membrane (CM). This study was designed as a crossover animal study. Four 5-mm tibia defects, 5 mm apart from each other, were surgically created on the tibias of 6 sheep. The defects were randomly filled with ABB + CM; PRF alone; ABB+PRF; or were left empty. The animals were euthanized on days 10, 20, and 40 post-operatively. No group showed any signs of bone necrosis. Inflammation was observed in 2 control and 3 test defects with no statistically significant difference between groups at each time point. The ABB + CM and ABB + PRF groups experienced the highest bone regeneration ratios. No differences between the empty-defect and PRF groups were observed in regard to bone regeneration. No statistical difference was observed between the ABB+PRF and ABB + CM groups in regard to bone regeneration and the amount of residual graft material at each time point. The use of PRF should be preferred due to its autogenous origin, low cost, and ease of use.

Thermal oxidation and hydrofluoric acid treatment on the sandblasted implant surface: A histologic histomorphometric and biomechanical study.

OBJECTIVES: This study aimed to analyze and compare the topographical, chemical, and osseointegration characteristics of a sandblasted acid-etched surface (SLA group), a sandblasted thermally oxidized surface (SO group), and a surface chemically modified by hydrofluoric (HF) acid (SOF group). MATERIALS AND METHODS: Following the preparation and characterization of the relevant surfaces, 90 implants (30 for each group) were placed on the pelvic bone of six sheep. Resonance frequency analysis (RFA), insertion (ITV), removal torque value (RTV), and histomorphometric analyses (BIC%) were performed after three and 8 weeks of healing. The results were analyzed by nonparametric tests (p < 0.05). RESULTS: The roughness value (Ra) in the SOF group was significantly lower than the SLA and the SO group (p = 0.136, p < 0.001, respectively). This resulted in a substantially inferior ITV 14.83 N/cm (SD: 4.04) than those achieved in the SLA and SO groups (19.50 (SD: 6.07) and 20.17 N/cm (SD: 8.95), respectively; p = 0.001). A statistically significant change in the RFA from the baseline (47.36 ISQ, SD: 6.93) to the 3rd week (62.56 ISQ, SD: 5.29) was observed in the SOF group only (p = 0.008). The highest postplacement RFA and RTV values were measured from the SLA group (61.11 ISQ, SD: 7.51 and 78.22 N/cm, SD: 28.73). The early-term (3rd week) BIC% was highest in the SO group (39.93%, SD: 16.14). After 8 weeks, the differences in BIC% values were statistically not significant. CONCLUSIONS: Adjunct HF acid application on the thermally oxidized surface did not provide an additional benefit compared to the sandblasted and acid-etched surface (SLA group).

Combined effect of parathyroid hormone and strontium ranelate on bone healing in ovariectomized rats.

OBJECTIVE: Parathyroid hormone (PTH) enhances bone healing. Strontium ranelate (SR) is an antiresorptive agent that increases bone formation. Reports about combined effects of PTH and SR on local bone regeneration in osteoporotic subjects are limited. We aimed at investigating the efficacy of PTH and SR for promoting new bone formation in critical-sized defects of ovariectomized rats. MATERIALS AND METHODS: Parathyroid hormone- and/or SR-containing poloxamer implant tablets with/without chitosan microparticles were delivered locally to calvarial defects of 90 Wistar rats. Biopsies were analyzed histologically and histomorphometrically at 4 and 8 weeks of healing. RESULTS: Histomorphometry revealed that PTH alone promoted new bone formation at 4 weeks but the efficiency declined in 8 weeks. There was no positive effect of SR alone on bone formation at 4 or 8 weeks. Calvarial defects treated with PTH+SR combinations showed statistically significant greater new bone formation than either treatment alone at both time intervals. Tissue responses were modest and supported the good biocompatibility of the biomaterials used. CONCLUSION: Parathyroid hormone and SR combinations can be effective for calvarial bone regeneration of ovariectomized rats. PTH plus SR may have potential use as bone graft material in orthopedic and dental surgery to enhance bone healing and osseointegration.

Vascular endothelial growth factor and biphasic calcium phosphate in the endosseous healing of femoral defects: An experimental rat study.

BACKGROUND/PURPOSE: The presence of adequate bone volume is a critical factor in rehabilitative dentistry. Despite the use of many promising alloplasts, success in stimulating bone formation has been limited, mostly due to poor local biological response. Growth factors have been introduced to stimulate angiogenesis and new bone formation. This histologic and histomorphometric study aimed to evaluate the effect of vascular endothelial growth factor (VEGF) and a biphasic alloplastic graft material (BA) on the healing of endosseous defects in rats. MATERIALS AND METHODS: Twenty male Wistar rats were used. Two critical-sized bone defects were created in both the right and left femurs of each rat. Each defect was randomly assigned to be treated with VEGF, BA, or VEGF + BA, or to be left empty as a control. Half of the animals were sacrificed after 1 week, and the remaining half were sacrificed after 2 weeks. Inflammation, necrosis, and new bone areas were evaluated by means of histologic and histomorphometric analyses. RESULTS: Compared to the control group, defects treated with VEGF alone or in combination with BA showed higher rates of bone formation (33.10-46.60%) on Day 7. Additionally, VEGF significantly reduced inflammation and necrosis (P < 0.001). However, the differences were no longer discernable on Day 14. CONCLUSION: VEGF makes a significant contribution to angiogenesis and osteogenesis in the early stages of bone defect healing, and its combination with an osteoconductive grafting material (BA) may further enhance new bone formation.

Histologic and Histomorphometric Comparison of Bone Regeneration Between Bone Morphogenetic Protein-2 and Platelet-Derived Growth Factor-BB in Experimental Groups.

Efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human platelet-derived growth factor-BB (rhPDGF-BB) delivered via absorbable collagen sponge (ACS) on bone formation was evaluated in guinea pig tibias. Three-millimeter-circular bone tibia defects were created in 24 guinea pigs assigned randomly to 4 groups according to the following defect filling materials: ACS only, rhBMP-2+ACS, rhPDGF-BB+ACS, or empty. New bone formation was evaluated histologically and histomorphometrically at 15 (early healing) and 45 days (late healing). Mean new bone per total defect area ratio was 0.73, 0.57, 0.43, and 0.42 in rhBMP-2+ACS, rhPDGF-BB+ACS, ACS only, and empty groups at early healing, respectively. During early healing, significantly more new bone formation was observed in rhBMP-2+ACS and rhPDGF-BB+ACS groups than in the control groups. New bone formation was significantly higher with rhBMP-2+ACS than with rhPDGF-BB+ACS. Mean new bone per total defect area ratio was 0.81, 0.86, 0.74, and 0.75 in the rhBMP-2+ACS, rhPDGF-BB+ACS, ACS only, and empty groups at late healing, respectively. During late healing, new bone formation was significantly higher in the rhPDGF-BB+ACS group relative to both control groups, but the results did not differ significantly from those in the rhBMP-2+ACS group. New bone formation in the rhBMP-2+ACS group did not change significantly between the healing periods. In the rhPDGF-BB+ACS group, however, new bone formation was significantly higher in the late healing period. Both growth factors accelerated new bone formation in the early healing period. Although rhBMP-2 was more effective in the early healing period, the effects of rhPDGF-BB were longer lasting.

Evaluation of the autogenous bone block transfer for dental implant placement: Symphysal or ramus harvesting?

BACKGROUND: The absence of sufficient bone volume is the most relevant problem in implant dentistry. Grafting from exogenous sources may provide a limited gain but exhibits poor performance in large bone defects. Autogenous bone block transfer (ABBT) from the mandibular symphysis and ramus has been used with varying rates of success. The aim of this study was to compare the efficacy of symphysal and ramus ABBT for the restoration of lost horizontal alveolar bone volume in the anterior maxilla. Implants placed in the augmented areas were also evaluated. METHODS: The maxillary alveolar bone deficits of 32 patients were treated by similar-sized autogenous bone blocks (7 × 7 × 4 mm) harvested from the symphysis or ramus area. After 4 to 5 months of healing, implants were inserted. At the end of the osseointegration period, the implants were restored by fixed prostheses. Baseline bone thickness was determined by Cone beam computed tomography and was compared to post-op and one-year post-loading bone thickness values where the implants were inserted. Any complications or consequences were noted. The success and survival of the 45 implants were evaluated. The results were analyzed using the Student t-test and Fisher's exact test (p < 0.05). RESULTS: Post-op complications were frequent in both groups. Baseline bone thickness values were similar at the beginning of the study (p = 0.71) and exhibited a significant increase after the ABBT surgery (6.29 (SD 0.86) and 6.01 (SD 0.92) mm in the symphysis and ramus groups, respectively). The amount of bone thickness gain was 4.34 mm (SD: 0.92) and 4.36 mm (SD: 1.01) in the symphysis and ramus groups, respectively. After one year, the mean surface resorption was 0.6 mm (SD: 0.78) and 0.80 mm (SD: 0.56) for the symphysis and ramus groups, respectively (p = 0.089). The success and survival rates of the implants were 94.11 and 96.42 %, respectively. No graft failures were observed. CONCLUSIONS: Both symphysal and ramus ABBT procedures were successful for the restoration of a horizontal bone defect in the anterior maxilla. Ramus harvesting may be advisable due to fewer complications. Implants placed in the grafted regions exhibited a high success and survival rate within the one-year follow-up period.

Clinical evaluation of the stability of implants placed at different supracrestal levels.

PURPOSE: The aim of this study was to evaluate the stability during healing and before loading of implants placed at two different supracrestal levels according to their collar texture. MATERIALS AND METHODS: This retrospective study included patients who received posterior implants with the same macro design. Implants with a machined collar were placed 0.3 mm above the crestal bone (M group), while those with a laser-microtextured collar were placed 1 mm above the crestal bone (L group). All implants healed in a single stage with healing abutments. Implant stability quotient (ISQ) values were determined using resonance frequency analysis immediately after implant placement during surgery and after 1, 4, 8, and 12 weeks after surgery. Other evaluated factors for stability included the implant diameter and length and the site of placement (maxilla or mandible). RESULTS: In total, 103 implants (47 L, 56 M) were evaluated. The median ISQ values at baseline and 1 week after placement were significantly higher for the M group than for the L group (p=0.006 and p=0.031, respectively). There were no differences at the subsequent observation points. The ISQ value was higher for wide-diameter than regular diameter (p=0.001) and mandibular implants than maxillary implants (p=0.001 at 0-8. weeks; p=0.012 at 12 weeks) at all observation points. When diameter data were neglected, the implant length did not influence the ISQ value at all observation points. CONCLUSION: Our results suggest that submerging implant more inside bone may only influence primary stability. Moreover, the implant diameter and site of placement influence primary and secondary stability before loading, whereas the implant length does not when its diameter is not accounted for.

Sinus Augmentation With Platelet-Rich Fibrin in Combination With Bovine Bone Graft Versus Bovine Bone Graft in Combination With Collagen Membrane.

The purpose of this study was to compare the efficacy between the use of bovine bone graft material and platelet-rich fibrin (PRF) mixture (test group) and bovine bone graft material and collagen membrane combination (control group) in 2-stage maxillary sinus augmentation. According to specific inclusion/exclusion criteria, patients treated between 2008 and 2012 were selected. Panoramic radiographs were used for radiologic assessments. To evaluate the relationship between sinus-graft height and each implant, the bone level (BL) was divided by implant length (IL). To evaluate the change in the height of grafted sinus, the grafted sinus floor above the lowest part of the original sinus height (GSH) was divided by the original sinus height (OSH). Samples taken during implant surgery were used for histologic and histomorphometric analyses. Twenty-five patients, 32 augmentation surgeries, and 66 one-stage implants were included in the study. No implant loss or complication was observed in either group. There were no statistical differences according to new bone formation (P = .61) and biomaterial remnant (P = .87). During the evaluation period, the test group showed statistically less change in the BL/IL ratio (P = .022). The difference of GSH/OSH ratio was found to be insignificant between groups (P = .093). It was observed that the grafted sinus covering the implant apex and sinus floor was above the original sinus height in both groups. It may be concluded from this study that both combinations can be successfully used for sinus augmentation. Further studies evaluating different graft materials and PRF combinations in the early phases of healing would be beneficial.

The comparison of two techniques to increase the amount of peri-implant attached mucosa: free gingival grafts versus vestibuloplasty. One-year results from a randomised controlled trial.

AIMS: The objective of this randomised controlled trial was to compare the efficacy of two techniques for increasing the amount of keratinised mucosa around implants: free gingival grafts versus classic vestibuloplasty. MATERIALS AND METHODS: Sixty-four patients with 64 implants presenting keratinised mucosa <1.5 mm and showing signs of peri-implant mucositis were randomly assigned to two groups. Thirty-two implants received free gingival grafts (FGG group) while 32 implants were treated via vestibuloplasty (VP group). Plaque Index (PI), Gingival Index (GI), probing depth (PD) and the width of attached mucosa (WAM) were measured at baseline and 1, 3, 6 and 12 months following surgery. RESULTS: WAM in the FGG group was significantly greater than the VP group at 3, 6 and 12 months (P = 0.000). In the FGG group, the final gain in WAM was greater (2.36 mm in FGG group, 1.15 mm in VP group) (P = 0.000) and the postoperative relapse was smaller (2.00 mm in FGG group, 3.06 mm in VP group) (P = 0.000). The VP group had higher PD values at 3, 6 and 12 months (P = 0.02, P = 0.024, P = 0.000, respectively). CONCLUSIONS: The application of FGG is a more predictable method for enhancing the width of attached mucosa in the vicinity of implants compared with classic vestibuloplasty.

Efficacy of quick-release lornoxicam versus placebo for acute pain management after dental implant surgery: a randomised placebo-controlled triple-blind trial.

AIM: To assess the efficacy of quick-release lornoxicam (LNX) on patient-reported acute pain after dental implant surgery. MATERIALS AND METHODS: The study included subjects in good general health, aged 18 to 65 and scheduled to receive a maximum of three implants in the same quadrant. Participants received either 8 mg LNX or placebo and were asked to use the medications in case of pain in the first 120 min after implant surgery. Assessment of efficacy was performed using self-assessment questionnaires for the evaluation of pain intensity and pain relief for 12 h post dosing. Patients were also asked to record the rescue analgesic number. Evaluation of patient satisfaction was assessed using a 7-point scale. Safety was evaluated by the incidence of adverse events. RESULTS: A total of 83 (LNX/placebo, 42/41) patients who met the inclusion criteria and finished the evaluation period were included in the study. The proportion of patients experiencing postoperative pain was significantly lower in the LNX-treated group compared to the placebo group. Patients in the LNX group reported significantly higher pain relief scores than the placebo group. Twenty-nine patients in the placebo group and 6 patients in the LNX group used rescue analgesics. The number of used rescue analgesics was 1.024 ± 0.79 and 0.167 ± 0.43 in the placebo and LNX groups, respectively. The level of patient satisfaction was significantly higher in the LNX-treated patients (P = 0.007). No adverse events were reported during the study period. CONCLUSIONS: Quick-release LNX is effective in postoperative acute pain control and has a high safety profile following dental implant surgery.

Evaluation of periimplant crevicular fluid prostaglandin E2 and matrix metalloproteinase-8 levels from health to periimplant disease status: a prospective study.

OBJECTIVE: To compare the levels of prostaglandin E2 (PGE2) and matrix metalloproteinases-8 (MMP-8) in periimplant crevicular fluid (PICF) after osseointegration and loading. MATERIALS AND METHODS: PICF was collected at the 3rd, 6th, 12th, and 18th months after implantation of 72 implants. PGE2 and MMP-8 levels besides clinical parameters were evaluated. RESULTS: Plaque and gingival index at the 6th, 12th, and 18th months presented higher values. Probing depth showed an increase after the 12th month. PGE2 presented a higher value at the 18th month. MMP-8 level demonstrated higher values after the sixth month. PGE2 and MMP-8 demonstrated positive correlations with gingival index and probing depth. CONCLUSION: The detection of PGE2 and MMP-8 in PICF serve to be useful for monitoring the course of periimplant disease. MMP-8 promises to be an early signal of periimplant inflammation.

Evaluation of 316 narrow diameter implants followed for 5-10 years: a clinical and radiographic retrospective study.

OBJECTIVES: Narrow diameter implants (NDIs; diameter >3.75 mm) are useful in replacement of missing incisor teeth and when the bucco-lingual width of the edentulous crest is insufficient. The present study evaluated the success and survival rates, peri-implant parameters, mechanical and prosthetic post-loading complications of NDIs followed over a 10-year period. MATERIAL AND METHODS: Three hundred and sixteen NDIs were inserted into 139 patients and restored with 120 prostheses. Clinical and radiographic assessment data were collected during recall visits. Implant success (SC), cumulative survival rate (CSR), marginal bone loss (MBL), peri-implant conditions and prosthetic complications were assessed. Cox proportional hazards regression analysis, Kaplan-Meier survival curves with the log-rank test and life table analysis were used to evaluate the outcome of NDIs within comparable subgroups. MBL and peri-implant parameters measured annually were further analyzed. RESULTS: The mean follow-up time was 9.1 years (range: 60-124 months). Twelve implants were lost in the healing phase and two during function. The mean MBL in the maxilla and the mandible was 1.32 +/- 0.13 and 1.28 +/- 0.3 mm, respectively, after 10 years. SC and CSR were 91.4% and 92.3%, respectively, after 124 months. Smoking and posterior localization were associated with an increased risk of failure. Cement loosening (16.8%) was the most common prosthetic complication. No implants were fractured. CONCLUSIONS: NDIs can be used with confidence where a regular diameter implant is not suitable. MBL around NDIs occurred predominantly within 2 years of loading and was minimal thereafter. Further studies are required to clarify the possible risks associated with smoking and posterior placement.