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.

The Effects of Maxillary Expansion on Late Alveolar Bone Grafting in Patients With Unilateral Cleft Lip and Palate.

PURPOSE: The purpose of this study was to answer the research question of whether maxillary expansion provides enough postgraft stimulation to decrease the volume loss of alveolar bone grafts in patients with cleft lip and palate (CLP) who missed the appropriate treatment time. MATERIALS AND METHODS: This study was designed as a prospective controlled clinical trial. Thirty patients in the permanent-dentition stage with unilateral CLP were divided into 2 groups: In group I (mean age, 19.33 ± 5.16 years), slow maxillary expansion was performed before secondary alveolar bone grafting (SABG); in group II (mean age, 19.93 ± 3.99 years), slow maxillary expansion was performed 6 weeks after SABG. The iliac crest was preferred as a donor site for autogenous bone graft harvesting. Cone beam computed tomography images were taken 1 week, 6 months, and 12 months postoperatively. The volume and density of the alveolar bone graft were calculated using Mimics software (version 13.1; Materialise, Ann Arbor, MI), and SPSS software (version 19.0; IBM, Armonk, NY) was used for statistical analysis. RESULTS: The bone graft volume loss was significantly higher in group I than in group II after 6 months of healing (P = .003). The increase in bone density was significantly higher in group II than in group I after 6 months of healing (P = .017). Although the mean loss of volume was lower and the mean density of the bone graft was higher in group II, there was no significant difference between the 2 groups in terms of mean graft volume and mean bone density 12 months after the operation. For groups I and II, the mean bone graft volume loss was 46.3% and 34.6%, respectively, and the mean increase in bone density was 16% and 49%, respectively, after 12 months of healing. CONCLUSIONS: Maxillary expansion after late SABG may be taken into consideration as a treatment choice in selected unilateral CLP patients to provide bone graft stimulation.

Histomorphometric Evaluation of Bone Formation in Peri-Implant Defects Treated With Different Regeneration Techniques: An Experimental Study in a Rabbit Model.

PURPOSE: The aim of this study was to investigate the healing of artificially created peri-implant circumferential bone defects using three bone-regeneration techniques. MATERIALS AND METHODS: Rabbit tibias (24 rabbits), in which bone defects (9-mm diameter, 4-mm depth) were created and implant beds (3-mm diameter, 6-mm depth) were prepared in the middle of the created defects, were used as the experimental model. Dental implants (3.0 × 10 mm) were inserted, and the peri-implant bone defects were grafted with demineralized freeze-dried bone allograft (DFDBA) plus saline solution, DFDBA plus platelet-rich fibrin (PRF), or DFDBA plus rifamycin. After 4 weeks, the animals were euthanized and the implants with surrounding bone were removed. Undecalcified histomorphometric examinations with toluidine blue staining were performed, and the bone-to-implant contact (BIC) and percentage of new bone formation were evaluated. RESULTS: The BIC was 50.94% ± 24.39% in the DFDBA-plus-saline solution group, 60.07% ± 4.91% in the DFDBA-plus-rifamycin group, and 73.43% ± 3.86% in the DFDBA-plus-PRF group. The percentage of new bone formation at the defect area was 37.61% ± 1.70% in the DFDBA-plus-saline solution group, 48.51% ± 2.80% in the DFDBA-plus-rifamycin group, and 63.09% ± 2.10% in the DFDBA-plus-PRF group. In terms of new bone formation and BIC, the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups were significantly different from the DFDBA-plus-saline solution group. The difference between the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups was also statistically significant. CONCLUSIONS: The addition of PRF or rifamycin to DFDBA had a significant positive effect on bone healing in peri-implant bone defects. The DFDBA-plus-PRF group showed the highest percentages of new bone formation and BIC.

Histological Evaluation of the Effect of Concentrated Growth Factor on Bone Healing.

OBJECTIVES: The aim of this study was to evaluate the effects of concentrated growth factors (CGF) on the healing of peri-implant bone defects in an animal model. STUDY DESIGN: Twenty 4-month-old New Zealand White rabbits, each with an average weight of 3.5 kg, were used in this blinded, prospective, experimental study. Two implants were placed and 2 peri-impant defects were prepared in each rabbit tibia. Bone defects were created monocortically in the tibia of each rabbit using a trephine burr with a diameter of 8 mm. The implants were installed in each hole. The rabbits were divided into 4 groups: in group E, the defect was left empty; in group CGF, the defects were filled only with CGF; in group AB, the defects were filled with autogenous bone; and in group AB+CGF, the defects were filled with autogenous bone and CGF. The animals were euthanized at week 8 postimplantation. All implants from the 20 animals were fixed in 10% formalin and evaluated histomorphometrically. RESULTS: The mean defect area was highest in group E and lowest in group CGF+AB (P <0.05). The area of the defect differed significantly between groups AB and CGF+AB (P <0.05), but not between groups CGF and E. Implant-to-bone contact was lowest in group E. In the defect areas of groups CGF, AB and CGF+AB, a small amount of new bone formed around the implant. CONCLUSIONS: In this animal model of a peri-implant bone defect, restoration was achieved using a combination of autogenous bone and CGF. Further studies are needed to determine the behavior of CGF when used in the repair of bone defects in humans.

Evaluation of relationship between preoperative bone density values derived from cone beam computed tomography and implant stability parameters: a clinical study.

OBJECTIVES: The aim of this study was to explore the efficacy of bone density value derived from cone beam computed tomography (CBCT) by evaluating its correlation with implant stability parameters including insertion torque value (ITV) and radiofrequency analysis in relation to different clinical variables including location, gender, age, bone quality, and implant diameter. MATERIAL AND METHODS: A total of 65 implants were placed in 17 patients. The bone densities of implant recipient sites were preoperatively recorded using CBCT. Bone quality was subjectively assessed, which depends on the stiffness of the jawbone according to the Lekholm and Zarb index during drilling procedure. The maximum ITV of each implant was recorded using a digital torque meter during implant placement. Resonance frequency measurements were taken using an Osstell Mentor immediately after implant placement. Data were analyzed statistically. RESULTS: The mean bone density, insertion torque, and implant stability quotient values of all implants were 556 ± 80, 37.4 ± 3.3 Ncm, and 73.8 ± 7.2, respectively. Statistically significant correlations were found between bone density values from CBCT and implant stability parameters in relation to all variables. CONCLUSION: Bone density assessment using CBCT is an efficient method and significantly correlated with implant stability parameters and Lekholm and Zarb index. Thus, it is possible to predict initial implant stability and possibility of immediate or early loading using CBCT scans prior to implant placement.

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.

Does cone beam computed tomography-derived bone density give predictable data about stability changes of immediately loaded implants?: A 1-year resonance frequency follow-up study.

The aim of this clinical study was to evaluate whether preoperative bone density value derived from cone-beam computed tomography (CBCT) gives predictable data about primary and secondary stability characteristics of immediately loaded dental implants under different clinical variables. A total of 77 immediately loaded implants placed in 23 patients were included the study. Bone density values of the implant recipient sites were recorded using CBCT. The maximum insertion torque values (ITVs) of the implants were recorded using a digital torque meter during surgery. Resonance frequency measurements were taken using the Osstell Mentor at 4 time points; immediately after surgery (implant stability quotient [ISQ]0) and after 1 (ISQ1), 3 months (ISQ3), and 12 months (ISQ12) of loading. Data were analyzed statistically. The mean bone density and ITVs of all implants were 565 ± 81 and 36.8 ± 3.8 N · cm, respectively. The mean ISQ values were 73.6 ± 5.8 at baseline, 71.1 ± 6.5 after 1 month, 74.8 ± 5.6 after 3 months, and 76.6 ± 5.1 after 12 months of loading. Statistically significant differences were observed between ISQ0 and ISQ1 (P < 0.001), and ISQ0 and ISQ12 (P < 0.001), but not between ISQ0 and ISQ3 (P > 0.05). In regard to stability changes over time, statistically significant correlations were found between bone density values from CBCT and ISQ follow-up measurements, and between ITV and ISQ follow-up measurements in all examination periods. Thus, it is possible to predict primary and secondary stability characteristics of immediately loaded implants by using preoperative CBCT scan and perioperative ITV.

Osteointegration of a bisphenol-a-glycidyl-dimethacrylate composite and its use in anterior skull base defects: an experimental study in an experimental design model of cerebrospinal fluid leak.

OBJECT: Promising clinical results were reported in watertight closure of anterior skull base defects (ASBDs) with bisphenol-a-glycidyl-dimethacrylate (bis-GMA)-based materials to prevent the cerebrospinal fluid leaks. However, interrelation of these materials with surrounding bones in histologic level, referred to as the osteointegration, has not been reported in the anterior skull base. In addition, an illustrative case with an ASBD that was repaired using a bis-GMA composite has been presented. METHODS: Twenty New Zealand rabbits were divided into 4 groups: control and sham groups consisted of 2 and 6 rabbits, respectively. The "skull base defect" group (n = 6) underwent a unifrontal craniectomy and an iatrogenic ASBD followed by creating a dural defect to obtain a cerebrospinal fluid leak. Similar bony and dural defects were acquired in the "repair with bis-GMA based allograft" group (n = 6), but the bony defect was closed with bis-GMA-based allograft. RESULTS: All animals in the "skull base defect" group died in 3 weeks after surgery. There were no animal losses in the "repair with bis-GMA based allograft" group at the sixth month. Histologic evaluation revealed complete osteointegration of bis-GMA composite with surrounding bones. CONCLUSIONS: bis-GMA based allograft achieved a watertight repair of the ASBD. Histologic findings of this study showed that bis-GMA composite is a reliable material to be used in the closure of anterior skull base bony defects.

Direct current electric stimulation in implant osseointegration: an experimental animal study with sheep.

In an effort to obtain a high-quality bone-implant interface, several methods involving alteration of surface morphological, physicochemical, and biochemical properties are being investigated. The aim of our study was to increase the osseointegration rate and quality and decrease the waiting period of dental implants before loading by using a microelectric implant stimulator device. It imitates microelectrical signals, which occur in bone fractures described in terms of piezoelectric theory. A single dental implant (Zimmer Dental), 3.7 mm in diameter, was inserted into the tibia of sheep bilaterally. Twenty-four dental implants were inserted into 12 sheep. Implant on the tibia of each sheep was stimulated with 7.5 µA direct current (DC), while the other side did not receive any stimulation and served as a control. Animals were sacrificed 1, 2, and 3 months after implantation. Bone segments with implants were processed with unclassified method. The determination of new bone formation and osseointegration around the dental implants was investigated by means of undecalcified method, histomorphologically. No statistically significant difference in bone-to-implant contact (BIC) ratio, osteoblastic activity, and new bone formation was found between the stimulation group and the control group at the late phase of healing (4, 8, and 12 weeks). No evidence was found that electric stimulation with implanted 7.5 µA DC is effective at late phase implant osseointegration on a sheep experimental model.

Comparison of bovine-derived hydroxyapatite and autogenous bone for secondary alveolar bone grafting in patients with alveolar clefts.

PURPOSE: The aim of this retrospective study was to compare the long-term outcomes of secondary alveolar bone grafting (SABG) using bovine-derived hydroxyapatite versus autogenous bone. PATIENTS AND METHODS: The subjects in this study were 23 patients with unilateral cleft lip and palate (13 male, 10 female) who underwent SABG from 2004 through 2009. The patients were recalled and examined to evaluate the success of the long-term outcomes of SABG. In group 1, there were 12 patients (7 male, 5 female) who underwent grafting with anterior iliac crest bone; in group 2, 11 patients (6 male, 5 female) underwent grafting with bovine-derived hydroxyapatite. RESULTS: The mean ages at grafting were 13 ± 3.76 years in group 1 and 10.82 ± 2.6 years in group 2 (P = .134). The mean lengths of follow-up were 47.33 ± 13.79 months in group 1 and 67.82 ± 10.36 months in group 2 (P = .002). Pocket depth, periodontal index, and gingival index scores were similar and indicated acceptable periodontal status in the 2 groups. The results for patient satisfaction were not statistically different (P > .05). There was no statistically significant difference between the 2 groups when results of the Chelsea scale were analyzed (P > .05). The radiologic results showed an 83.4% success rate in group 1 and a 100% success rate in group 2 (P = .478). When the densitometric values for cleft sites were analyzed, the difference between the 2 groups was not statistically significant (P = .190). CONCLUSIONS: Bovine-derived hydroxyapatite is as successful as the iliac graft for the SABG procedure.

Anorganic bovine-derived hydroxyapatite vs ß-tricalcium phosphate in sinus augmentation: a comparative histomorphometric study.

The choice of augmentation material is a crucial factor in sinus augmentation surgery. Bovine-derived hydroxyapatite (BHA) and beta-tricalcium phosphate (ß-TCP) have been used successfully in sinus augmentation procedures. Choosing one of these materials for sinus augmentation is still controversial. The aim of this clinical study was to compare the biological performance of the new BHA graft material and the well-known synthetic ß-TCP material in the sinus augmentation procedure. The study consisted of 23 patients (12 male and 11 female) who were either edentulous or partially edentulous in the posterior maxilla and required implant placement. A total of 23 two-step sinus-grafting procedures were performed. BHA was used in 13 patients, and ß-TCP was used in 10 patients. After an average of 6.5 months of healing, bone biopsies were taken from the grafted areas. Undecalcified sections were prepared for histomorphometric analysis. The mean new bone formation was 30.13% ± 3.45% in the BHA group and 21.09% ± 2.86% in the ß-TCP group (P = .001). The mean percentage of residual graft particle area was 31.88% ± 6.05% and 34.05% ± 3.01% for the BHA group and ß-TCP group, respectively (P = .047). The mean percentage of soft-tissue area was 37.99% ± 5.92% in the BHA group and 44.86% ± 4.28% in the ß-TCP group (P = .011). Both graft materials demonstrated successful biocompatibility and osteoconductivity in the sinus augmentation procedure. However, BHA appears to be more efficient in osteoconduction when compared with ß-TCP.

Osseointegration and stability of a modified sand-blasted acid-etched implant: an experimental pilot study in sheep.

OBJECTIVE: The aim of this pilot study was to compare the early-term osseointegration characteristics of standard (SLA) and modified sand-blasted and acid-etched (modSLA) implants in an experimental animal model. MATERIAL AND METHODS: A total of 30 SLA and modSLA implants were placed to the tibiae of three sheep and the insertion torque value (ITV) and resonance frequency analysis (RFA) measurements were performed. RFA measurement was repeated on 3 and 6 weeks healed implants after which the animals were sacrificed for histomorphometric analysis. Bone-to-implant contact was assessed on the non-decalcified sections. Six weeks healed implants were also subjected to the reverse torque test (RTT). Results were analyzed by the Friedman test, Kruskal-Wallis test and Spearman rank correlation test. RESULTS: All implants reached to a strong primary stability with a mean 36.13 ± 2.47 and 35.47 ± 2.85 N/cm ITV. In the surgical stage, RFA values for SLA and modSLA implants were found to be 72.27 ± 3.17 and 71.6 ± 2.87, respectively. After 3 weeks of healing, mean BIC% (80.64 ± 13.89%) and RFA value (76.8 ± 1.14) of modSLA implants were significantly higher (P=0.0002) than that of SLA implants (64.39 ± 21.2 BIC% and 74.2 ± 4.76 RFA). However, no statistically significant difference between SLA and modSLA implants was recorded after 6 weeks of healing. Both implants revealed similar results in the RTT test (115.2 ± 4.14 and 117 ± 4.47 N/cm for SLA and modSLA implants, respectively). No correlation was found between RFA and BIC%. CONCLUSION: Within the limits of this pilot study, it can be concluded that modSLA implants achieve a higher bone contact and stability at earlier time points when compared with SLA implants.

Comparative study of the osseointegration of dental implants after different bone augmentation techniques: vascularized femur flap, non-vascularized femur graft and mandibular bone graft.

OBJECTIVES: The purpose of this study was to evaluate the osseointegration of the dental implants placed into the mandible augmented with different techniques in pigs. MATERIAL AND METHODS: Four adult domestic pigs were used. Horizontal augmentation of the mandible was performed in animals by using vascularized femur flap (VFF), non-vascularized femur graft (NVFG) and monocortical mandibular block graft (MG). After 5 months of healing 10 dental implants were placed into each augmented site. The pigs were sacrificed after 3 months of healing. Undecalcified sections were prepared for histomorphometric analysis. RESULTS: Mean bone-implant contact (BIC) values for implants placed into MG, NVFG and VFF were 57.38 ± 11.97%, 76.5 ± 7.88%, 76.53 ± 8.15%, respectively. The BIC values of NVFG and VFF group were significantly greater than MG group (P<0.001). On the other hand, there was not statistically significant difference between NVFG group and VFF group (P=0.999). CONCLUSION: NVFG as well as VFF can be considered as a promising method for augmentation of alveolar defects and the placement of the implants. The selection of non-vascularized graft or vascularized flap depends on the condition of the recipient site.

The effect of bovine bone graft with or without platelet-rich plasma on maxillary sinus floor augmentation.

PURPOSE: The purpose of this study was to compare Unilab Surgibone (USB) (Mississauga, Ontario, Canada), a bone xenograft (bovine), with platelet-rich plasma (PRP) and USB without PRP to augment the human maxillary sinus in preparation to receive dental implants. PATIENTS AND METHODS: Patients who had bilateral pneumatized maxillary sinuses were included. Sinuses on one side were augmented with the USB-PRP combination and formed the study group, whereas the opposite-side sinuses were augmented with USB alone and served as controls. Bone biopsy specimens were taken during implant placement at 6.8 ± 0.9 months after maxillary sinus floor augmentation. Resonance frequency analysis measurements were performed at implant placement (first control) and before the prosthetic stage (second control), at 6.5 ± 0.7 months after implant surgery. RESULTS: There were 10 patients (7 men and 3 women; mean age, 53.7 ± 0.8 years). Integration between new bone and residual grafts was histologically observed in all samples. The volumes of soft tissue were 59.9% ± 7.5% and 57.8% ± 4.4% in the control and study groups, respectively; residual graft, 21.9% ± 6.6% and 23.6% ± 5.9%, respectively; new bone, 15.8% ± 4.8% and 16.0% ± 3.8%, respectively; and trabecular bone, 64.7% ± 22.5% and 69.1% ± 18.6%, respectively. A positive correlation was found between new bone volume and trabecular bone volume (P = .0001). The mean Implant Stability Quotient (ISQ) values were 71.7 ± 4.9 and 70.3 ± 5.7 in the control and study groups, respectively, at first control and 75.4 ± 6.4 and 74.4 ± 6.4, respectively, at second control. The mean ISQ values at second control in both groups were significantly higher than at first control (P = .043 and P = .028, respectively). No statistically significant differences were observed between groups (P > .05). CONCLUSION: The combination of USB and PRP does not have any effect on new bone formation and implant stabilization.

Effects of zoledronic acid on healing of mandibular fractures: an experimental study in rabbits.

PURPOSE: The purpose of the present study was to evaluate the effects of systemically administered zoledronic acid (ZA) on mandibular fracture healing in a rabbit model using radiodensitometric, biomechanical, histologic, and histomorphometric methods. MATERIALS AND METHODS: A total of 36 skeletally mature male New Zealand white rabbits were used. The rabbits were randomly divided into 2 groups. A mandibular corpus fracture was created experimentally in all 36 rabbits. The experimental group was administered an intravenous, single dose of 0.1 mg/kg ZA, and the control group was administered only saline infusion during the procedure. All rabbits were sacrificed on the 21st postoperative day. Digital radiodensitometric analysis, a 3-point bending test, and histologic and histomorphometric examinations were performed on the harvested hemimandibles. The data were analyzed statistically. RESULTS: Biomechanical testing data showed that ZA treatment resulted in a significant increase in the healed bone strength. This result was supported by the radiologic, histologic, and histomorphometric findings. CONCLUSIONS: The results of the present study have revealed that systemic administration of ZA accelerates and improves the bone healing of mandibular fractures.

The Effect of Application of Combined Bovine-Derived Anorganic Bone Graft and Hemostatic Plant Extract on Bone Regeneration.

PURPOSE: To evaluate the effect of bovine-derived anorganic bone graft (ABB) in combination with hemostatic plant extract (ABS) on bone regeneration. MATERIALS AND METHODS: Three bone defects were created via an extraoral approach on the mandibles of nine domestic pigs. The first defects were filled with ABS solution (0.3 mL/defect) in a transporting agent of ABB (0.3 cc/defect), whereas the second defects were filled with ABS (0.3 mL/defect) in microcapsules for controlled drug release, combined with ABB (0.3 cc/defect) again. The third defects were left empty. After a 10-week healing period and the sacrification, undecalcified sections were prepared for histomorphometric analysis. RESULTS: The mean total area of hard tissue was 29.54% ± 3.2% in the control group, 59.78% ± 5.4% in the conventional group, and 63.67% ± 4.2% in the microsphere group (P < .001). The mean area of newly formed bone was 29.54% ± 3.2% in the control group, 34.79% ± 3.9% in the conventional group, and 37.95% ± 5.3% in the microsphere group (P = .003). The mean residual graft area was 24.99% ± 2.4% in the conventional group and 25.71% ± 4.4% in the microsphere group (P = .730). CONCLUSION: The combined usage of ABS and ABB in both ways increased bone regeneration statistically. However, there was no significant difference between the two methods for ABS delivery systems in terms of new bone regeneration.

Effect of zoledronic acid on osseointegration of titanium implants: an experimental study in an ovariectomized rabbit model.

PURPOSE: Zoledronic acid (ZA), a new-generation intravenous bisphosphonate, exhibits the greatest affinity for bone mineral with the longest retention, thereby leading to its ability to be dosed at annual intervals in the treatment of osteoporosis. The purpose of this preliminary study was to evaluate the effects of systemic administration of a single dose of ZA on osseointegration and bone healing around titanium dental implants. MATERIALS AND METHODS: Thirty-six female New Zealand rabbits (aged 6-12 months) were used in this study. Rabbits were randomly assigned to 1 of 3 groups: sham control group (SH), ovariectomy group (OVX), and OVX and ZA group (OVX + ZA). Animals in the OVX and OVX + ZA groups were subjected to bilateral ovariectomy, whereas animals in the SH group were sham operated. Eight weeks later, 1 implant was placed in each tibia of the animals. ZA was administered in the OVX + ZA group during the implantation, whereas the OVX and SH groups received saline solution infusions. All of the subjects were sacrificed 8 weeks after the implantation, and tibial specimens were harvested. Histomorphometric bone-to-implant contact analysis, resonance frequency analysis, removal torque testing, and digital radiographic absorptiometry were administered, and the data were statistically analyzed. RESULTS: Histomorphometric, resonance frequency, and radiodensitometric analyses showed significant improvement in osseointegration of implants in the OVX + ZA group compared with the OVX group. However, the differences in removal torque results between the groups were not statistically significant. CONCLUSIONS: The results of this study suggest that systemic ZA administration may improve osseointegration of titanium implants placed in estrogen-deficient states of bone.

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.