Does the Outcome of Graft Materials at Dental Implant Sites Differ Between Patients With Normal and Compromised Bone Health?

The objective of this paper was to assess the outcome of bone graft material at alveolar bone augmentation sites combined with dental implants in postmenopausal women with compromised bone health by evaluating cone beam computerized tomography (CBCT) scans at multiple time points.CBCT scans were analyzed on 55 postmenopausal women with compromised bone health status to determine the fate of alveolar bone augmentation. CBCT scans were taken immediately after surgery and 9 and 24 months postoperatively. The patient's medication regimens and durations were recorded, and the pixel intensity value (PIV) was measured and standardized using scoring criteria and visual assessment. Statistical analyses included 2-sample t tests for continuous variables and Fisher's exact tests for categorical variables.Among the normal patients, 73% received a grade 2 visual score, and 27% received a grade 1 visual score. After 24 months, 45% of patients received a grade 2 score, and 27% received a grade 3 score. In the osteoporotic group receiving medication, 77% of participants received a grade 1 visual score at the 9-month postoperative evaluation, while 23% received a grade 2 score. At the 24-month assessment, 55% of patients received a grade 1 score, 41% received a grade 2 score, and only 5% received a grade 3 score. Notably, although the graft material did not remodel into native bone, it was a scaffold for implants in controlled osteoporotic patients. The study's results show that the pixel intensity values of particulate graft materials are similar across the three different time points, suggesting that the graft material's pixel intensity value remains constant in postmenopausal women with osteoporosis. The study's limitations include a small sample size and a restricted 24-month follow-up period. This limited time frame may need to capture long-term changes or variations in graft materials adequately. Future research should include a larger sample size and have a longer follow-up duration to provide a more comprehensive understanding of the change in graft materials between patients with normal and compromised bone health.

Dental implant and bone augmentation treatment in bone-compromised patients: Oral health-related quality of life outcomes.

STATEMENT OF PROBLEM: Patient-reported outcomes represent an additional and often overlooked measure of dental implant and bone augmentation treatment. Few implant studies have evaluated patient-reported outcomes in those with systemic bone compromise. PURPOSE: The purpose of this cohort study was to assess oral health-related quality of life (OHRQoL) outcomes in postmenopausal women receiving dental implants with normal bone density or mild osteopenia ("healthy" group; all DXA T-scores at femoral neck, total hip, and L1-L4 spine>-2.0) versus moderate osteopenia or osteoporosis ("bone compromised" group; any DXA T-score at femoral neck, total hip, or L1-L4 spine≤-2.0). MATERIAL AND METHODS: A total of 115 patients were recruited at the University of Connecticut School of Dental Medicine as part of a standard of care, prospective, nonrandomized cohort study. All participants received 1 of 3 bone augmentation procedures with implant placement. At baseline and at various intervals after implant placement, OHRQoL was measured by using the Oral Health Impact Profile-14 (OHIP-14) and surveys of patient expectations and satisfaction. These measures were compared between healthy and bone compromised groups (α=.05). RESULTS: For all OHRQoL measures across linear mixed effects models, no significant differences were found between bone groups at baseline and at each time point after implant placement (P>.05). Using the minimally important difference (MID) for OHIP-14, no definitive clinical differences were found in patient outcomes between bone groups at all postimplant time points (P>.05). From baseline to 24 months after implant placement, both healthy and bone compromised groups exhibited significant improvements in OHIP-14 and patient expectations scores (P<.05). While no within group differences were found in patient satisfaction scores, the mean satisfaction score remained high over time in both groups. CONCLUSIONS: Patient-reported outcomes as measured through OHIP-14, patient expectations, and patient satisfaction surveys suggest similar postimplant OHRQoL improvement in healthy and bone compromised individuals. OHRQoL improvements between bone groups were similar both in continuity and in scope, with no evidence of statistically significant score differences between groups at 24 months after implant placement across all measures and with no definitive evidence of clinical differences as measured by OHIP-14 MID comparisons across all timepoints.

Bone microRNA-21 as surgical stress parameter is associated with third molar postoperative discomfort.

OBJECTIVE: To evaluate an association between bone levels of inflammation/oxidative stress mediators and postoperative discomfort after third molar conventional or piezosurgery. MATERIAL AND METHODS: Twenty-six subjects with bilaterally impacted mandibular third molars, who underwent either piezo or conventional surgery, were included in a split-mouth design study. MicroRNA-21 (miR-21) expression, interleukin-1 beta (IL-1ß), and vascular endothelial growth factor (VEGF) proteins, as well as superoxide dismutase (SOD) activity in alveolar bone, were evaluated. Pain intensity, the first pain appearance, analgesic first use and total dose taken, trismus, and swelling were clinically recorded. RESULTS: MiR-21 expression was higher while VEGF protein was lower in piezosurgery vs. conventional groups. The differences in IL-1ß protein and SOD activity were not significant between groups. The pain intensity on the first day was significantly decreased in piezosurgery group. The first pain appearance and the first analgesic taken were reported sooner in conventional vs. piezosurgical group. Significantly pronounced trismus on the third day following conventional surgery was found. In conventional group, significantly increased trismus was observed on the third compared to the first postoperative day. MiR-21 showed significant correlation with the first pain appearance. CONCLUSION: Delayed onset of less pronounced postoperative pain after piezosurgical vs. conventional extraction of impacted lower third molar was significantly associated with expression of bone miR-21. CLINICAL RELEVANCE: Alveolar bone miR-21 may reflect surgical stress and is associated with third molar postoperative pain onset.

Implant-guided supracrestal alveolar bone growth using scaffolds, BMP-2, and novel scaffold-retaining device.

OBJECTIVE: To evaluate the efficacy of various scaffold systems and a Ti scaffold-retaining device with and without non-glycosylated rhBMP-2 (BMP-2) for increasing the vertical alveolar bone growth in the intra-oral mini-pig model. METHODS: Forty-eight Straumann Bone Level implants with hydrophilic (SLActive) surfaces were partially embedded in mandibles of 12 adult mini-pigs with the shoulder of the implant located 3 mm above the bone crest. Twenty-four implants were placed in conjunction with BMP-2 (50 µg) incorporated within resorbable scaffolds. Twenty-four additional control implants were placed with scaffolds only. Scaffolds were placed around the implant and stabilized with a newly developed Ti "umbrella" scaffold retainer. Scaffolds included (i) HA-coated collagen (Healos); (ii) biphasic HA/ß-TCP crystals (Straumann Bone Ceramic, SBC); and (iii) SBC crystals infused with polyethylene glycol (PEG) hydrogel. Eight test and control pairs for each scaffold group were implanted. At 9 weeks, soft tissue healing was assessed and the extent of new vertical bone was evaluated with microCT and histomorphometry. RESULTS: microCT analysis revealed a mean of 167 ± 47 mm3 new supracrestal mineralized tissue volume formation around the test sites where BMP-2 was released from the scaffold whereas the control group (no BMP-2) showed a significantly lower mineralized tissue volume of 106 ± 55 mm3 . The SBC+BMP-2 group had the highest mineralized tissue volume of 189 ± 36 mm3 . Histomorphometry showed bone-to-implant contact of 54.5% for the test groups and 33.3% for the control groups and new vertical bone growth of 2.2 ± 1.0 and 1.0 ± 0.9 mm, respectively. The SBC+BMP-2 group again demonstrated the best outcome (2.7 ± 0.4 mm). The qualitative scoring of soft tissue dehiscence showed that the presence of BMP-2 yielded far superior outcomes, 0.63 vs. 1.75 for all control implant sites (with scores ranging from 0, reflecting no soft dehiscence, to 4, showing a completely exposed umbrella). CONCLUSION: The release of BMP-2 from a SBC scaffold adjacent to a hydrophilic, rough Ti implant and scaffold retention umbrella consistently regenerated the greatest volume and height of new vertical bone along the length of the implant.

Comparison of bone morphogenetic protein-2 delivery systems to induce supracrestal bone guided by titanium implants in the rabbit mandible.

OBJECTIVE: To compare the ability of three non-glycosylated/rhBMP-2 (BMP-2) delivery systems to induce supracrestal bone. MATERIAL AND METHODS: Thirty-six custom SLActive dental implants were partially embedded in transverse orientation into the posterior mandibles of 18 adult rabbits with the head of the implant located 3 mm supracrestal. Delivery of BMP-2 (30 µg) from the following materials was studied: (1) Ti implant + BMP-2 with hydroxyapatite (HA)-coated collagen (Col/HA) scaffold, (2) Ti implant with Col/HA infused with PEG hydrogel + BMP-2, or (3) Ti implant with HA/ß-TCP/PEG hydrogel scaffold + BMP-2. Scaffolds were secured with a metal "umbrella." Non-BMP-2 contralateral controls were included. MicroCT imaging and histological analysis was performed after 10 weeks to assess new supracrestal bone formation. In vitro BMP-2 release studies were conducted. RESULTS: All treatment groups displayed new supracrestal bone formation. Ti + BMP-2 with Col/HA (3.0 ± 0.2 mm) and Ti with Col/HA/PEG hydrogel + BMP-2 (2.7 ± 0.4 mm) had significantly greater (P < 0.05) outcomes than without BMP-2. Maximum bone volume occurred in the Ti implant with HA/ß-TCP/PEG hydrogel scaffold + BMP-2 group. CONCLUSIONS: The use of an implant system composed of a partially inserted Ti implant, adjacent scaffold and scaffold stabilizer resulted in the formation of new supracrestal bone across all test groups with and without BMP-2. Delivery of BMP-2 directly from the Ti implant increased bone height, BIC and bone volume as compared to no BMP-2 when a Col/HA was used, but did not improve performance of the HA/ß-TCP/PEG scaffold.

CBCT evaluation of buccal bone regeneration in postmenopausal women with and without osteopenia or osteoporosis undergoing dental implant therapy.

STATEMENT OF PROBLEM: Because alveolar bone augmentation in women with osteoporosis/osteopenia has an uncertain prognosis, objective and reliable methods should be used to study standard surgical approaches. PURPOSE: The purpose of this clinical study was to evaluate bone regeneration 9 months after bone augmentation and implant placement in postmenopausal women with different levels of systemic bone health by using cone beam computed tomography (CBCT) and to test proof of concept for this measurement approach. MATERIAL AND METHODS: A subset of 14 participants was analyzed in a best practice study of postmenopausal women receiving dental implants and simultaneous horizontal ridge augmentation. Women were categorized as osteopenic/osteoporotic or normal based on the results of preoperative dual-energy x-ray absorptiometry. All implant study sites received a particulate graft and/or buccal plate expansion. The study sites were evaluated with CBCT preoperatively, immediately postoperatively, and 9 months postoperatively. Nonparametric statistics were used for all analyses. The related samples Wilcoxon signed rank test was used to assess the differences in bone width between time points (α=.05 for all tests). RESULTS: After 9 months, 13 out of 14 participants showed increased bone width compared to the preoperative baseline measurements. The increase was statistically significant for the participants with osteoporosis/osteopenia (P=.007), but not for those with normal bone health (P=.066). The CBCT scans showed that mineralized tissue buccal to the implant surface had the radiographic appearance of mature bone. CONCLUSIONS: CBCT showed evidence of bone regeneration, with an increase in alveolar ridge width in postmenopausal osteopenic/osteoporotic women subsequent to surgical reconstruction.

Evaluation of a Polyethylene Glycol-Osteogenic Protein-1 System on Alveolar Bone Regeneration in the Mini-Pig.

Alveolar bone regeneration associated with the local release of osteogenic protein-1 (OP-1) from a polyethylene glycol (PEG) scaffold was evaluated in 14 mini-pigs. Following extraction of mandibular teeth and 26-weeks of healing time, standardized bone defects were created bilaterally in the posterior mandibles (3 sites for each hemimandible) that were randomly assigned to treatment groups. Seven treatments groups were compared: 4 different concentrations of the PEG/OP-1 test system (n = 14 for each), a positive control (collagen/OP-1, n = 14), a negative control (PEG only, n = 7) and nontreated defects (n = 7). Each animal provided all test and control groups. The animals were sacrificed after 3 weeks of healing and samples were processed for histology and histomorphometry. Three weeks after implantation, there were positive clinical responses for all test groups. Earlier bone maturation was observed in the test groups that had higher concentrations of OP-1 (0.25, 0.5, or 1 mg/mL) compared to the negative control group (PEG alone), the low concentration group (0.1 mg/mL), and the positive control group (collagen/OP-1). However, histomorphometric quantitative analyses did not reveal any statistical difference between any of the groups. No residual PEG biomaterial or inflammatory responses to the biomaterial or growth factor were observed. This study confirmed the safe local delivery of OP-1 from PEG hydrogel. Alveolar bone regeneration was not statistically different between tests groups, negative control (PEG alone) or commercial positive control (collagen/OP-1). The semi-quantitative analysis, however, showed a trend in favor of the higher concentrations of OP-1 to induce faster bone maturation.

The relationship between implant stability and bone health markers in post-menopausal women with bisphosphonate exposure.

OBJECTIVES: The authors assessed the relationship between implant stability and bone turnover markers in patients with and without a history of bisphosphonate (BP) exposure for treatment of osteopenia/osteoporosis. MATERIALS AND METHODS: One dental implant site was evaluated in 58 post-menopausal women with a spectrum of bone health in a "best practice" prospective cohort study. Each site had a previous or simultaneous bone augmentation procedure. BP exposure at enrollment was categorized as "never" or "past/current" exposure. Implant stability was assessed by resonance frequency analysis (RFA ISQ) at surgery and 8 weeks post-implant. Bone turnover markers, C-telopeptide collagen crosslinks (sCTX) and procollagen -1 N-terminal telopeptide (P1NP), were measured pre-treatment, 1, and 8 weeks following implant surgery. RESULTS: Mean age was 62.4 ± 6.8 years; 66 % were osteopenic/osteoporotic. Average RFA ISQ at placement for all participants was 63.5 ± 11.3, at 8 weeks post-surgery 74.2 ± 9.4 (p < 0.01). Among "past/current" BP users, there was a significant negative correlation between RFA ISQ values at 8 weeks post-implant placement and sCTX and P1NP values at 1 week (ρ = -.65 and ρ = -.55, respectively; p < 0.01) and 8 weeks (ρ = -.64 and ρ = -.52, respectively; p < 0.05). CONCLUSION: RFA ISQ values increased between implant placement and 8 weeks post-surgery demonstrating successful osseointegration. Lower bone turnover was associated with better implant stability among patients with a history of BP exposure. CLINICAL RELEVANCE: Further investigation of the relationship between BP exposure and implant stability is warranted in a larger population, as results may strongly impact on clinical practice decisions.

Use of a perforated scaffold-retaining abutment to achieve vertical bone regeneration around dental implants in the minipig.

OBJECTIVE: To evaluate the effect of perforated scaffold retainers used in conjunction with dental implants and osteoinductive scaffolds to regenerate vertical supracrestal alveolar bone in an intraoral minipig model. MATERIALS AND METHODS: Three months after extraction of mandibular premolars and first molars from six adult minipigs, two titanium (Ti) custom implants were placed bilaterally in the edentulous mandibles for a total of four implants per animal. The upper 2.5 mm of the implant was left above bone level and covered with: (1) wide-neck healing caps; (2) perforated, overhanging custom scaffold retainers (umbrellas); or (3) scaffold retainers and demineralized minipig bone allograft (DBM) and nonglycosylated bone morphogenetic protein 2 (ng/rhBMP-2)-treated implants. All constructs were submerged beneath soft tissue flaps for 8 weeks. Two dental implant surfaces were compared: SLA and SLActive. Samples were retrieved after 8 weeks and analyzed by radiography, micro-computed tomography and histomorphometry. RESULTS: All implants were stable at the end of the experiment. Histomorphometry revealed that the use of the scaffold-retaining umbrellas led to increased, but not statistically significant, vertical bone regeneration as compared to the use of wide-neck healing caps (1.0 ± 0.4 mm vs 0.6 ± 0.3 mm). The combination of DBM and ng/rhBMP-2 released from the surface of the SLA implant resulted in the greatest amount of vertical bone regeneration (2.1 ± 0.2 mm). The bone-to-implant contact was similar for all groups. Mucosal dehiscence areas with healing cap or custom scaffold retainer exposures were reduced in the presence of ng/rhBMP-2. CONCLUSIONS: The combined use of custom perforated Ti scaffold retainers, DBM, and ng/rhBMP-2 regenerated a substantial amount of vertical supracrestal alveolar bone around Ti implants in an intraoral minipig model.

Bone quality evaluation: comparison of cone beam computed tomography and subjective surgical assessment.

PURPOSE: To examine the relationship between dental cone beam computed tomography (CBCT) gray scale values and Hounsfield units (HU), and whether the gray values of edentulous sites correlate with the subjective clinical bone quality assessed at surgery. MATERIALS AND METHODS: Two radiographic phantoms containing varying concentrations of either dipotassium hydrogen phosphate or calcium hydroxyapatite (HA) were imaged using multislice CT or CBCT. Reconstructed DICOM data were analyzed to examine the relationship between CBCT gray values and HU. Presurgical CBCT scans from 52 patients who underwent implant placement in the posterior sextants were used. The gray values of the edentulous implant sites were measured and compared with the subjective bone quality assessed at surgery. RESULTS: There was a strong correlation between CBCT gray values and HU. CBCT gray values increased linearly with increasing calcium HA or bone equivalent density material. CBCT gray values measured at edentulous implant sites ranged from -455 to 642, with a trend of decreasing gray values with bone quality type. The median gray values for the four subjective bone types were: 362 (type 1), 214 (type 2), 76 (type 3), and -454 (type 4). CONCLUSIONS: CBCT gray values can be used to infer bone density and may provide a valuable aid to predict bone quality at potential implant sites.

Implant-guided vertical bone growth in the mini-pig.

OBJECTIVE: To attain and describe guided vertical bone regeneration around titanium (Ti) and titanium zirconium (Ti-Zr) dental implants utilizing non-glycosylated recombinant human bone morphogenetic protein-2 (ng/rhBMP-2), biomaterial scaffolds and a scaffold retainer. MATERIALS AND METHODS: Thirty-two modified Straumann TE implants were partially embedded in the mandibles of eight adult mini-pigs. Pre-shaped resorbable scaffolds were placed around the implant and shielded and stabilized with a newly developed Ti custom scaffold retainer (umbrella) or wide-neck (WN) healing caps to stabilize the scaffold. Ng/rhBMP-2 (50 µg) was applied to the supracrestal portion of the implant or incorporated within the scaffold. At 9 weeks, soft tissue healing was assessed. Vertical bone regeneration outcomes including bone height, bone-to-implant contact (BIC) and bone volume were assessed by micro-computed tomography and histology. RESULTS: Soft tissue healing at the test sites (+ng/rhBMP-2/+scaffold) appeared to be substantially better than the control sites (-ng/rhBMP-2/-scaffold). Bone height, BIC percentage and bone volume were all similar regardless of whether WN healing caps or umbrella scaffold stabilization was used for all biomaterial scaffolds tested. WN healing cap test sites showed greater new bone height and BIC as compared with aggregate data from the control sites (P=0.05). Comparison of aggregate data from the umbrella test sites showed greater BIC and new bone volume as compared with aggregate data from the control sites(P=0.05). CONCLUSION: Vertical bone regeneration was successfully attained utilizing ng/rhBMP-2, biomaterial scaffolds and a scaffold retainer.

An evaluation of BMP-2 delivery from scaffolds with miniaturized dental implants in a novel rat mandible model.

The purpose of this study was three-fold: (a) to develop a new small animal model to evaluate dental implant systems that recapitulates aspects of the challenging intraoral environment, (b) screen several scaffolds for in vivo bone forming efficacy when used to deliver non-glycosylated bone morphogenetic protein-2 (BMP-2) together with a miniaturized titanium (Ti) dental implant, and (c) identify correlations between in vitro BMP-2 release rates and in vivo results. The scaffolds tested were: (1) collagen-hydroxyapatite composite (Col/HA), (2) polyethylene glycol hydrogel (PEG-hydrogel), and (3) Col/HA infused with PEG-hydrogel (Col/HA/PEG-hydrogel). BMP-2 delivery directly from the Ti implants rather than from the scaffolds was also tested. MicroCT analyses at 4 weeks showed that the maximum volume and height of new bone occurred when BMP-2 (10 µg) was delivered from the Col/HA/PEG-hydrogel scaffolds. BMP-2 delivery from the Ti implant was not as effective as from the scaffolds. While in vitro BMP-2 release was highest for the PEG-hydrogel, the scaffold most successful in vivo was the Col/HA/PEG-hydrogel scaffold because it had the necessary mechanical strength to perform well in the mandibular bone environment. The in vitro release studies suggested a threshold dose of 5 µg which was borne out by the in vivo dose response studies.

Implant system for guiding a new layer of bone. Computed microtomography and histomorphometric analysis in the rabbit mandible.

OBJECTIVE: To prove the concept that an implant system with osteoconductive surface characteristics and an osteoinductive scaffold material has the capacity to guide vertical supracrestal bone growth in a rabbit mandible onlay model. MATERIAL AND METHODS: Thirteen adult white New Zealand rabbits each received custom-designed dental implants. All implants had sandblasted, acid-etched (SLA) surfaces, with the coronal aspect (3 mm) of each implant was left outside the lateral aspect of posterior mandibular bone, but covered by periosteum, muscle, subcutaneous tissue, and skin. Bone formation around implants placed adjacent to osteoinductive demineralized bone matrix (DBM) scaffolds were compared with contralateral implants without scaffolds in six rabbits using micro-CT imaging. Bone formation around implants with scaffolds from seven additional rabbits was measured using both micro-CT imaging and quantitative histology. RESULTS: At 8 weeks, new supracrestal bone was seen adjacent to all implants placed with DBM and two implants without DBM. The mean supracrestal bone heights achieved for implants with and without DBM scaffolds as measured by micro-CT was 2.1+/-0.9 and 0.8+/-0.9 mm, respectively (P=0.008). Histomorphometric analysis illustrated that supracrestal bone-to-implant contact for implants with DBM scaffolds was 58.1+/-14% and that mean supracrestal bone height was 2.4+/-0.6 mm. CONCLUSIONS: Successful implant-guided supracrestal osteogenesis has been demonstrated in a rabbit model with the combined use of osteoconductive implant surfaces, an osteoinductive scaffold, and a device that prevents soft tissue downgrowth and provides scaffold stabilization.

Simultaneous dental implant placement and endoscope-guided internal sinus floor elevation: 2-year post-loading outcomes.

AIMS: To determine whether endoscope-guided sinus elevation procedures can be consistently used to create sufficient bone support for stable implant placement and long-term implant success. MATERIAL AND METHODS: Sixty-two implants were surgically placed into 30 patients (14 men and 16 women) following internal sinus elevation without the use of graft material. Panoramic radiographs were made pre-, post-operative and after 24 months in order to evaluate the peri-implant bone and maxillary sinuses. Resonance frequency analysis (RFA) was used to evaluate implant stability immediately upon placement and just before prosthesis delivery. RESULTS: The average pre-operative height of the maxillary alveolar bone was 8.4+/-2.2 mm at the premolar and 7.3+/-3.1 mm at the molar regions. The average bone gain was 3.5+/-1.8 and 4.5+/-1.9 mm in the premolar and molar sites, respectively. Clinical parameters and the RFA (4 and 12 weeks post-operative) outcomes show sufficient stability (ISQ=60) of the inserted implants. Three implants failed during the healing period of 12 weeks. The overall implant success rate was 94%. After loading, no further implant failure was observed. The overall success rate after beginning of implant loading was 100%. CONCLUSIONS: Sinus floor elevation is a well-established procedure for augmentation of the atrophic maxillary posterior region. The minimally invasive internal sinus floor elevation procedure visually guided by an endoscope helped to prevent, diagnose and manage complications such as sinus membrane perforation. The clinical outcomes of this study show that endoscope-controlled internal sinus floor elevation combined with implant placement results in low intra operative trauma, good implant stability upon placement, low incidence of post-operative symptoms and high success rates after 24 months of loading.

Growth of new bone guided by implants in a murine calvarial model.

New methods to increase vertical bone growth are needed to permit dental implant placement in patients with low alveolar ridge height after extended periods of tooth loss. While ectopic rodent models are typically used to evaluate new osteogenic implant surface coatings, a more relevant intramembraneous rodent model was needed to address the particular clinical need to grow a new layer of bone above an existing layer of bone. In this study we report on a novel murine calvaria model in which successful vertical bone growth around miniaturized dental implants was achieved when using non-glycosylated bone morphogenetic protein-2 (ng/rhBMP-2). Twenty CD-1 mice received two Ti implants each consisting of a Ti ring implant stabilized by a Ti screw into the occipital calvarial bone. Four groups were evaluated: control Ti, Ti+20 mug ng/rhBMP-2, hydroxyapatite (HA)-coated Ti, and HA+20 mug ng/rhBMP-2. The mice were sacrificed 21 days following implant placement. MicroCT analysis showed no new bone formation around the untreated Ti or the HA-coated implants, but demonstrated new bone growth in every dimension around and above the Ti+ng/rhBMP-2 and the HA+ng/rhBMP-2 treated implants. Histopathologic analysis showed that a thin fibrous capsule covered the untreated Ti implants. Limited bone-to-implant contact (BIC) was observed for the HA-coated implants, while in contrast both ng/rhBMP-2 treated groups exhibited extensive new supracalvarial woven bone that covered the implant and merged with the calvarial plate. Histomorphometrically, supracalvarial bone heights and bone widths and BIC were not statistically different from one another for the two ng/rhBMP-2 treated groups. However, the total supracalvarial bone surface area was significantly greater (p<0.05) for the Ti+ng/rhBMP-2 implants (7.2 mm(2)) than the HA+ng/rhBMP-2 (4.0 mm(2)) treated implants. The bone density within 1 mm around the implant was also significantly greater (p<0.05) for the Ti+ng/rhBMP-2 implants (9.9%) than the HA+ng/rhBMP-2 (4.0%) implants, indicating that HA coatings may not be required for sustained release when non-glycosylated BMP-2 is used. This new murine model is capable of discriminating between various bone augmentation strategies and may represent a clinically more relevant model for alveolar bone augmentation than the commonly used ectopic muscle pouch or long bone models.

Treatment options in distraction osteogenesis therapy using a new bidirectional distractor system.

PURPOSE: The purpose of this retrospective study was to compare a bidirectional distraction system with a unidirectional system with regard to bone height attained and the need for secondary graft procedures. MATERIALS AND METHODS: Unidirectional and bidirectional distractor devices were used for vertical augmentation of the maxilla and mandible in 2 separate groups of patients (n = 10 and n = 11, respectively). Clinical and radiographic outcome data were collected at postoperative follow-up examinations for up to 2.5 years. The height of the augmented alveolar ridge and the sagittal location of the bone fragment were measured on panoramic radiographs or lateral cephalograms. These data were analyzed with 1-way analysis of variance. Nonparametric data, such as treatment complications, were analyzed with the Fisher exact test. The dental implant survival data were evaluated with a Kaplan-Meier survival analysis. RESULTS: The difference in vertical bone gain observed between unidirectional and bidirectional groups (5.3 +/- 1.8 mm vs 6.1 +/- 2.3 mm) was not statistically significant. In the unidirectional group, additional autogenous bone grafting was required in 6 cases, while grafting was required in only 2 cases in the bidirectional group. This difference was due to the more precise control of the distraction process associated with the bidirectional distractor; however, it was not a statistically significant difference. Postaugmentation, 59 implants were placed in the augmented sites. These implants exhibited primary stability and were restored with good functional and esthetic results. CONCLUSIONS: The need for additional grafting procedures may be reduced in cases where the distraction vector is optimized, as generally seen with bidirectional distractor use.

A review of the association between osteoporosis and alveolar ridge augmentation.

OBJECTIVE: Because of increasing life expectancy and popularity of dental implants, surgeons face a larger number of osteoporotic patients who require bone augmentation. Relationship between low bone density/osteoporosis and bone graft success is still not clear. The purpose of this article is to review and summarize the literature regarding the success of alveolar bone augmentation in osteoporosis. STUDY DESIGN: The study design includes a literature review of relevant preclinical and clinical articles that address the association between osteoporosis and alveolar bone augmentation. RESULTS: Increased rate of complications such as resorption of bone graft, non-integration of bone graft, delayed healing time, and implant failure in augmented bone especially in the maxilla may be associated with compromised bone health. CONCLUSIONS: Despite the decreased success rate, osteoporosis is not an absolute contraindication for bone augmentation and dental implant placement. The modifiable risk factors for osteoporosis should be eliminated before surgery.

Design and use of a prefabricated fiber-reinforced composite substructure for the chairside replacement of missing premolars.

Fiber-reinforced resin composites (FRCs) have been used to make frameworks to support particulate resin composite veneers in the replacement of missing teeth. Both prosthetic laboratory-fabricated and chairside-fabricated approaches have been used with varying degrees of success. The chairside FRC fixed partial denture has been mainly used for anterior tooth replacement where the emphasis is on esthetics rather than withstanding occlusal load. This article focuses on the use of this technology in the chairside replacement of premolars. The concept of using a prefabricated framework is described in detail. This approach allows for the efficient delivery of a consistently made chairside prosthesis. This is in contrast with the time-consuming and less consistent result of FRC framework fabrication directly in the mouth. The goal for this concept is to use a premade framework finalized by the provider at chairside to provide medium- to long-term posterior tooth replacement, with minimal abutment tooth reduction.

Use of a prefabricated fiber-reinforced composite resin framework to provide a provisional fixed partial denture over an integrating implant: a clinical report.

The development of fiber-reinforced composites offers new possibilities in minimally invasive tooth replacement approaches. This article describes the use of a prefabricated fiber-reinforced composite resin framework for the chairside fabrication of a provisional fixed partial denture over an integrating implant. The framework fabrication, theory, and a clinical scenario are illustrated.

Fiber-reinforced composite prostheses.

Metal-free prosthetic dentistry continues to gain interest. Although the metal alloys contribute great strength and stiffness to restorations and prostheses, they do so at a considerable esthetic liability. Two somewhat divergent metal-free approaches to fixed tooth replacement continue to be developed for a variety of clinical applications. These are all-ceramic and all-polymeric systems. The polymeric prostheses are the subject of this article.