Effects of Orthognathic Surgery on Voice Characteristics.

PURPOSE: Orthognathic surgery not only corrects dentofacial deformities but also affects some vital structures involving voice production. The primary aim of this study was to analyze the effects of bimaxillary orthognathic surgery on voice characteristics of patients with class II and III skeletal deformities; the second aim was to evaluate possible associations among acoustic parameters, pharyngeal airway, and skeletal changes after surgery. MATERIALS AND METHODS: Using a prospective cohort study design, we enrolled a sample of patients who underwent bimaxillary orthognathic surgery in the university hospital between January 2018 and January 2019. Voice records and cone-beam computed tomography (CBCT) scans of the patients were acquired before surgery and 6 months after surgery. Pharyngeal airway volume, minimum cross-sectional area, hyoid bone position, and skeletal movements of the maxilla and mandible were assessed with Dolphin Imaging software using CBCT data as predictor variables. Acoustic analysis of voice samples (vowel/a/) were performed with Praat software as outcome variables. The within-group and between-group differences in data were analyzed using paired-sample and independent-sample t tests. The degree of relationship between voice and CBCT parameters was assessed using Pearson correlation and multiple regression analysis. RESULTS: The study sample comprised 33 patients; 14 patients had class II skeletal deformity and 19 patients had class III skeletal deformity. Orthognathic surgery in both patients with class II and III skeletal deformities resulted in significant changes in all the voice parameters (All P < .05). Only patients with class II skeletal deformity showed significant changes in airway parameters (increase; all P < .001) and hyoid bone positions (anterosuperior movement; P = .001 and P = .008, respectively). Multiple regression analysis showed that some specific structural changes significantly affected some specific acoustic parameters. CONCLUSIONS: Bimaxillary orthognathic surgery significantly changed the acoustic parameters of voice in patients with class II and III skeletal deformities. Some of the structural changes were significantly associated with some of the acoustic parameters.

Effect of Botulinum Toxin Type A on Mandibular Fracture Healing: An Experimental Study in Rabbits.

PURPOSE: The effect of botulinum toxin type A (BTX-A) on fracture healing of the long bones is controversial, and no controlled clinical or experimental study has investigated the effect of BTX-A on mandibular fractures. The purpose of this study was to investigate whether BTX-A injection into the masseter muscles affects bone healing by reducing the displacing forces in an unfavorable mandibular fracture model. MATERIALS AND METHODS: Forty-eight male New Zealand white rabbits were used. Ten units of BTX-A was injected into each masseter muscle in the animals in the BTX-A group, whereas saline solution was injected in the animals in the control group. A unilateral osteotomy and fixation with a microplate were performed. Bone healing was evaluated by radiodensitometric, biomechanical, histologic, and histomorphometric methods after 21 days. RESULTS: The mean bone mineral density in the fracture area was significantly higher in the BTX-A group (P = .038). The mean failure load and bending modulus values were significantly higher in the BTX-A group than in the control group (P = .032 and P = .005, respectively). The mean histologic bone healing scores, bone volume-total volume values, and trabecular diameter values were significantly higher in the BTX-A group than in the control group (P = .001, P = .001, and P = .026, respectively). CONCLUSIONS: BTX-A application into the masseter muscles improves bone healing of a unilateral mandibular fracture in rabbits.

Comparison of autogenous and allograft bone rings in surgically created vertical bone defects around implants in a sheep model.

OBJECTIVES: The aim of this study was to compare autogenous and allograft bone rings in surgically created vertical bone defects. MATERIAL AND METHODS: Four male, 1-year-old sheep were used in this study. In each sheep, eight vertical bone defects 7 mm in diameter were created using trephine drill in the iliac wing. Autogenous and allograft bone rings 5 mm in height and 7 mm in diameter were used for vertical augmentation around implants. The study consisted of four groups according to the bone ring type and amount of vertical augmentation, autogenous 2 mm, allograft 2 mm, autogenous 4 mm, and allograft 4 mm. Two of the animals were sacrificed after 4 months, and the remaining two animals were sacrificed after 8 months. Undecalcified sections were prepared from harvested samples. Histological assessment and histomorphometric analysis were performed. RESULTS: Autogenous 2 mm group showed higher values than allograft 2 mm group, and autogenous 4 mm group showed higher values than allograft 4 mm group in terms of bone area and bone-to-implant contact (BIC) after 4 months. However, allograft 2 mm group showed higher bone area and BIC values than autogenous 2 mm group after 8 months. Also, autogenous 4 mm and allograft 4 mm groups showed comparable results after 8 months. Allograft 2 mm and allograft 4 mm groups showed higher bone area and BIC values at 8 months compared with 4 months. CONCLUSIONS: Allograft bone ring looks promising in augmentation of surgically created vertical bone defects around implants after 8 months of healing.

Nonvascularized Cartilage Grafts Versus Vascularized Cartilage Flaps: Comparison of Cartilage Quality 6 Months After Transfer.

PURPOSE: Subchondral perfusion of osteochondral grafts has been shown to be important in preventing long-term cartilage degeneration. In carpal reconstruction, subchondral perfusion from the graft bed is limited. This study's purpose was to compare the histological characteristics of cartilage in osteochondral grafts supported by synovial imbibition alone to cartilage of vascularized osteochondral flaps that have both synovial and vascular pedicle perfusion. METHODS: Two adjacent osteochondral segments were harvested on the medial femoral trochlea in domestic 6- to 8-month-old pigs. Each segment measured approximately 12 mm × 15 mm × 17 mm. One segment was maintained on the descending geniculate artery vascular pedicle. The adjacent segment was separated from the pedicle to serve as a nonvascularized graft. A thin layer of methylmethacrylate cement was used to line the harvest site defect to prevent vascular ingrowth to the subsequently replaced specimens. The pigs were maintained on a high-calorie feed and returned to ambulation and full weight-bearing on the surgical legs. The animals were sacrificed after 6 months and the specimens were reharvested, sectioned, and examined. The cartilage was graded by 2 pathologists blinded to the origin of specimens as vascularized flaps or nonvascularized grafts. RESULTS: All specimens were assigned scores utilizing the International Cartilage Repair Society grading system. Scoring for chondrocyte viability, cartilage surface morphology, and cell and matrix appearance was significantly higher in the vascularized osteochondral group than in the graft group. CONCLUSIONS: When deprived of subchondral perfusion from underlying bone, osteochondral vascularized flaps in an intrasynovial environment demonstrate superior cartilage quality and survival compared with nonvascularized grafts. CLINICAL RELEVANCE: In locations in which perfusion from surrounding bone may be limited (ie, proximal scaphoid or proximal lunate reconstruction), articular reconstruction using vascularized osteochondral flaps will yield superior cartilage organization and architecture than nonvascularized osteochondral grafts. The clinical and functional relevance of this finding requires further study.

Effects of Local and Systemic Zoledronic Acid Application on Titanium Implant Osseointegration: An Experimental Study Conducted on Two Surface Types.

The aim of this study was to evaluate the effects of local and systemic zoledronic acid (ZA) applications on titaniumoksit ceramic blasted (TiO-CB)- and sandblasted large acid-grit (SLA)-surfaced titanium implant osseointegration. Twelve New Zealand White rabbits were used in the study, divided into 6 groups: the TiO-CB (TiO-CB-CNT) (n = 2) and SLA (SLA-CNT) (n = 2) control groups in which TiO-CB- and SLA-surfaced titanium implants were surgically inserted into rabbit tibias but no treatment was applied; the TiO-CB (TiO-CB-LZA) (n = 2) and SLA (SLA-LZA) (n = 2) local ZA groups in which 1 mL of normal saline solution containing 2 mg of ZA was injected into sockets and after this the implants were integrated; and the TiO-CB (TiO-CB-SZA) (n = 2) and SLA (SLA-SZA) (n = 2) systemic ZA groups in which a single infusion of 0.1 mg/kg of ZA was administered during surgical implant insertion. Following a period of osseointegration, bone implant contact (BIC) was recorded as a proportion of the total implant surface length in direct contact with the bone. Results of this study indicate that BIC was greater in the systemic ZA application groups than in the local ZA application groups, and BIC was greater in the local ZA groups than in the controls. Statistically significant differences in BIC were not detected between the TiO-CB- and SLA-surfaced implants in all the groups. Furthermore, this study did not reveal significant differences between the 2 types of surfaces due to similar average roughness values. Overall, systemic ZA application was found to be more effective in increasing BIC than local ZA application based on the results obtained by testing 2 implant surfaces.

A clinical prospective study on alveolar bone augmentation and dental implant success in patients with type 2 diabetes.

OBJECTIVES: The objective of this prospective, controlled clinical study was to determine the outcomes of dental implant therapy with staged guided bone regeneration procedures in patients with type 2 diabetes. PATIENTS AND METHODS: Twenty-four patients were included in the study. Half of the patients were diagnosed with type 2 diabetes mellitus (group 1) while the other half (group 2) of the patients consisted of patients without diabetes. The edentulous maxillary anterior/premolar regions with sufficient vertical height but inadequate horizontal width were treated with staged guided bone regeneration technique and with one or two implant-supported fixed restorations. The patients were followed up at least for 12 months. The parameters that were evaluated were radiographic evaluations on CBCT images and periapical radiographs, histomorphometric analysis, resonance frequency analysis (RFA) and wound-healing parameters. The data were analyzed statistically. RESULTS: A total of 43 implants were placed in 24 patients (22 implants in group 1 and 21 implants in group 2). The survival rates of implants were 100% for both groups. The success rate of implants was 95% for group 1 and 100% for group 2. None of the parameters including CBCT findings, RFA values, success rates and wound-healing scores showed a significant difference between the two groups. CONCLUSION: Staged guided bone regeneration is a feasible augmentation procedure for the treatment of horizontal bone deficiencies of the maxillary anterior/premolar regions in well-controlled type 2 diabetic patients.

Effects of zoledronic acid on physiologic bone remodeling of condylar part of TMJ: a radiologic and histomorphometric examination in rabbits.

OBJECTIVE: The purpose of the present study is to evaluate the effects of systemically administered zoledronic acid (ZA) on the physiological bone remodeling and the microarchitectural parameters of the condylar part of TMJ in a rabbit model. STUDY DESIGN: Thirty skeletally mature male New Zealand white rabbits were randomly divided into two groups. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA diluted with 15 mL of saline in a 15-minute perfusion with an infusion pump. The control group was administered only saline infusion for 15 minutes. All rabbits were sacrificed on the 21st postoperative day. Radiodensitometric and histomorphometric examinations were performed on the harvested mandibular condyles. The data were analyzed statistically. RESULTS: Radiodensitometric findings showed that ZA treatment resulted in a significant increase in the mineralization of mandibular condyle. This result was supported by the histomorphometric findings. CONCLUSION: The present study has revealed that a temporary delay in the physiological bone remodeling using single dose of ZA increases bone mineral content and makes the microarchitecture of the mandibular condyle more compact. These effects may be regarded as base data and considered in numerous clinical situations including TMJ.

Comparison of two different forms of bovine-derived hydroxyapatite in sinus augmentation and simultaneous implant placement: an experimental study.

PURPOSE: The aim of this study was to compare two different forms of bovine-derived hydroxyapatite (HA) in sinus augmentation and simultaneous implant placement. MATERIALS AND METHODS: The schneiderian membranes of 12 domestic pigs were elevated bilaterally through an extraoral approach. One sinus of each pig was grafted with bovine-derived granular HA (GHA) and the other was grafted with bovine-derived spongiosa block HA (BHA) (Unilab Surgibone). One dental implant was placed simultaneously into each grafted sinus. Animals were sacrificed after 6 months of healing. Primary implant stability (ISQi) and secondary implant stability (ISQf) were measured by resonance frequency analysis. Undecalcified sections were prepared for histomorphometric analysis. RESULTS: Mean ISQi values for implants placed in sinuses grafted with BHA and GHA were 68.8 +/- 5.0 and 68.2 +/- 3.7, respectively (P > .05). The mean ISQf value for implants in GHA increased to 72.0 +/- 5.1 and for implants in BHA decreased to 52.3 +/- 8.8 (P < .01). There was a statistically significant difference between ISQi and ISQf values for implants placed in BHA (P = .03) and GHA (P = .037). Mean bone-implant contact (BIC) in residual bone was 61.3% +/- 2.1% for BHA and 61.2% +/- 1.7% for GHA (P > .05). In augmented bone, mean BIC percentages were 20.6% +/- 2.1% and 35.6% +/- 1.8% for BHA and GHA, respectively (P = .002). Mean percentages of connective tissue were 61.9% +/- 9.5% and 48.4% +/- 10.7% (P = .036), new bone formation percentages were 12.8% +/- 5.5% and 27.9% +/- 4.6% (P = .012), and percentages of graft material around the implants were 25.3% +/- 5.8% and 22.4% +/- 6.2% (P > .05) for BHA and GHA, respectively. CONCLUSION: The form of graft material affects the osseointegration of implants in sinus augmentation and simultaneous implant placement.

Comparison of vascularized osteoperiosteal femur flaps and nonvascularized femur grafts for reconstruction of mandibular defects: an experimental study.

PURPOSE: The aim of this study was to compare the vascularized osteoperiosteal femur flaps (VFFs) and the nonvascularized femur grafts (NVFGs) for reconstruction of the mandibular defects of pigs. MATERIALS AND METHODS: Eight adult domestic pigs were used. The defects created in the mandibular angle were reconstructed with VFFs in 4 pigs (group 1) and NVFGs in the other 4 pigs (group 2). All the pigs were killed after 3 months of healing. Undecalcified and decalcified sections were prepared for histomorphometric analysis and histologic examination. Radiodensitometric absorptiometry was used to assess the differences in bone mineral density between the 2 groups. RESULTS: The bone volume to the total measured volume, trabecular thickness, and trabecular number were significantly greater in the VFF group than in the NVFG group (P < .05). However, the trabecular separation was significantly lower in the VFF group than the NVFG group (P = .029). Although the VFF group had a greater bone mineral density value than the NVFG group, the difference was not statistically significant (P = .057). In histologic examination, the viability of bone in the VFF group, enchondral bone healing, and lamellar bone formation in the NVFG group were apparent. CONCLUSIONS: The results of this study suggest that NVFGs have a greater bone resorption rate than do VFFs. Furthermore, the histomorphometric results imply that reconstruction of the mandibular defects with vascularized osteoperiosteal femur flaps will provide greater strength.

Dental and radiographic findings as predictors of osteoporosis in postmenopausal women.

AIM: The objective of this study was to evaluate the relationship between dental findings and osteoporosis in postmenopausal women. METHODS: One hundred and eight postmenopausal women were recruited for the study. All participants underwent dual X-ray absorptiometry (DXA). The number of remaining teeth, clinical attachment loss, pocket depth and mobility of each tooth were determined. Radiodensitometric analyses were performed on digital periapical radiographs utilizing an aluminum stepwedge technique. The appearance of inferior mandibular cortex posterior of the mental foramina region was scored according to the classification by Klemetti. RESULTS: The number of remaining teeth, attachment loss values, Klemetti Index scores and the radiodensitometric scores showed a significant relationship with skeletal bone density. CONCLUSION: Tooth loss, an increased clinical attachment level, reduced density on digital periapical radiographs and an eroded appearance of the inferior mandibular cortex in panoramic radiographs are associated with low-skeletal bone mineral density.

Placement of implants in the mandible reconstructed with free vascularized fibula flap: comparison of 2 cases.

The reconstruction of mandibular continuity defects after tumor resection with free vascularized bone flaps is considered to be a treatment option. Although the fibula flap presents many advantages, it does not offer sufficient bone height to restore the alveolar arch when reconstruction involves a dentate mandible. In this report, 2 patients who were referred to our clinic with reconstructed mandibles with diagnosis of amelablastoma are presented and compared. The mandibles of these patients were reconstructed with free vascularized fibula flaps. Whereas one of the reconstructed mandibles was vertically distracted before implant placement, distraction procedure was not carried out for the other patient. Increasing height of the fibula flap by distraction osteogenesis before implant placement in dentate mandible is desirable from a functional and esthetic point of view.

Histomorphometric evaluation of implants coated with enamel or dentine derived fluoride-substituted apatite.

OBJECTIVES: The aim of this study was to compare osseous healing characteristics of titanium implants coated with enamel-derived fluoride-substituted apatite (EFSA) or dentin-derived fluoride-substituted apatite (DFSA). METHODS: Fluoride-substituted apatite was derived from extracted human teeth with calcination method at 850 degrees C. DFSA and EFSA were separated and carefully ground with a blade grinder. Twenty-four titanium implants were prepared from a 99.99% pure titanium bar. EFSA and DFSA powders were sprayed separately on implants. As control group, unsprayed and sandblasted pure titanium implants were used. Eight adult rams were used in the study. One EFSA coated, 1 DFSA coated and 1 control implants were placed into right tibia of each rams. The rams were sacrificed after 6 months of healing. Undecalcified sections were prepared according to Donath's method and histomorphometric evaluation of implants was made. RESULTS: The mean bone contact percentage of DFSA-coated, EFSA-coated and control implants was 89.88%+/-2.34, 70.19%+/-13.11 and 53.12%+/-5.76 respectively. This study suggests that DFSA-coated implants achieved better bone contact than EFSA-coated implants (P<0.05). Also study groups presented better bone contact than control group (P<0.05). CONCLUSIONS: The results of this study show that although DFSA-coated implants achieved better bone contact, both DFSA and EFSA can be considered as appropriate coating materials.