Effects of condylar neck inclination and counterclockwise rotation on the stress distribution of the temporomandibular joint.

Three different kinds of condylar inclination were manually modelled anteriorly inclined condylar neck, vertical condylar neck, and posteriorly inclined condylar neck. Three different maxillary impactions were simulated to evaluate the effect of counterclockwise rotation. The von Misses stresses of the disc, compressive stresses of the glenoid fossa, and compressive stresses of the condyle were the highest in the models with posteriorly inclined neck and lowest in the models with vertical condylar neck design. Stresses of the temporomandibular joint increase with the counterclockwise rotation of the maxilla-mandibular complex. The posteriorly inclined neck should be considered a risk factor for condylar resorption with increased counterclockwise rotation.

Analysis of Satisfaction Levels in Completely Edentulous Patients Treated with Different Configurations of Implant- Supported Prostheses.

PURPOSE: To evaluate and compare patient satisfaction levels in edentulous patients treated with different configurations of implant-supported prostheses as well as previous prosthesis experiences before implant treatment. MATERIALS AND METHODS: A study population of 142 patients was identified and separated into four treatment groups: group 1 comprised 43 patients treated with an implant-supported overdenture in the mandible and conventional complete denture in the maxilla; group 2 comprised 32 patients treated with implant-supported overdentures in the maxilla and mandible; group 3 comprised 26 patients treated with an implant-supported overdenture in the mandible and a fixed prosthesis in the maxilla; and group 4 comprised 41 patients treated with implant-supported maxillomandibular fixed restorations. Questionnaires asking about masticatory performance, pronunciation, comfort, and social ability were used to evaluate treatment outcomes. RESULTS: The patients in group 4 were significantly more satisfied regarding masticatory performance than other treatment modalities. Visual analog scale (VAS) scores for comfort and social ability were similar in groups 3 and 4 and significantly higher than those in groups 1 and 2. The patients who used a conventional removable prosthesis before implant treatment were more satisfied with their implant-supported prosthesis regarding social ability (P = .03). CONCLUSIONS: The treatment design of an implant-supported fixed prosthesis in the maxilla and implant overdenture in the mandible provided a comparable level of satisfaction with maxillomandibular fixed prosthesis for edentulous patients. This combination served as a practical solution especially for patients with mandibular atrophy who would require extensive surgeries to support maxillomandibular fixed prostheses. In the maxilla, patient satisfaction with an implantsupported overdenture was not superior to that with a conventional prosthesis. Note that previous removable prosthesis experience may influence social comfort for patients.

Is Incisive Papilla a Good Landmark to Predict Clinical Outcomes and the Esthetic Perceptions of Edentulous Patients Treated with Implant-Supported Fixed Prostheses on Maxillae?

Purpose: To investigate the effect of incisive papilla on esthetic ratings and lip support for patients who are treated with implant-supported fixed prostheses on edentulous maxillae. Materials and Methods: A study population of 118 patients with maxillomandibular edentulism was identified. A self-administered questionnaire was used to evaluate treatment outcomes through a patient perspective. Also, clinical factors such as smile line, maxillary resorption, incisive papilla position, and lip support were evaluated. Results: Lip support has a significant effect on the facial esthetic scores of patients, while smile line and incisive papilla localization have not had a proven statistically significant effect on esthetic and facial esthestic scores of patients treated with implant-supported fixed prostheses on maxillae. Conclusion: Although the patients were diagnosed with disadvantageous clinical factors such as crestally localized incisive papilla, they still noted higher esthetic scores with their fixed prostheses. Factors that affect the esthetic perception of patients or their priorities should be investigated more to understand the reasons for patient satisfaction with prostheses.

Evaluating the changes in nasal airway volume and nasal airflow after surgically assisted rapid maxillary expansion.

OBJECTIVE: This study aims to compare the changes in the nasal airway volume and nasal airflow using acoustic rhinometry (AR), rhinomanometry (RMN), and dental volumetric tomography (DVT) after surgically assisted rapid maxillary expansion (SARME). STUDY DESIGN: Our study consists of 13 adults, 3 male and 10 female patients, aged between 15 and 26, with completed skeletal development. In our study, DVT imaging was obtained twice, preoperation and 3 months after expansion. AR and RMN measurements were recorded, and Visual Analog Score (VAS) and Nasal Obstruction Symptom Evaluation (NOSE) Scale surveys were scored at preoperation and 3 months after expansion. Nasopharyngeal-oropharyngeal airway volume and areas were calculated using the Romexis 3.8.3.R (Planmeca, Helsinki, Finland) and Nemotec V2019 (Madrid, Spain) software programs. IBM SPSS Statistics 22 (SPSS IBM, Armonk, New York) was used for statistical analysis. RESULTS: Comparing the preoperation and postexpansion measurements by both software programs revealed a statistically significant increase in the nasopharyngeal airway volume. No statistically significant change was observed in the oropharyngeal airway volume. Furthermore, we found a statistically significant increase in VAS but a significant decrease in NOSE. CONCLUSION: According to our findings, nasal airway volume increased after SARME, and although there was no significant change in nasal resistance, patients' quality of life increased significantly.

Stability of dental implants with sandblasted and acid-etched (SLA) and modified (SLActive) surfaces during the osseointegration period.

Background. The surface properties of implants are effective factors for increasing the osseointegration and activity of osteoprogenitor cells. This study compared the stability of dental implants with sandblasted and acid-etched (SLA) and modified surfaces (SLActive) using the resonance frequency analysis (RFA). Methods. In a split-mouth design, 50 dental implants with either SLA surface properties (n=25) or modified (SLActive) surface properties (n=25) were placed in the mandibles of 12 patients with a bilateral posterior edentulous area. Implant stability was measured using RFA (Osstell) at implant placement time and every week for 1, 2, and 3 months before the conventional loading time. Results. One week following the implantation, implant stability increased from 70 to 77.67 for SLA and from 71.67 to 79 for SLActive (P < 0.05). Stability improved each week except in the 4th week in SLActive surface measurements. No significant differences were observed between the groups at 2 and 3 months (P > 0.05). Conclusions. For both implant surfaces, increased stability was observed over time, with no significant differences between the groups.

Assessment of changes in masseter muscle by three-dimensional close-range photogrammetry after Botulinum toxin type-A injection: A case report with review of literature.

Masseter muscle hypertrophy (MMH) is a benign, unilateral or bilateral, painless enlargement. Treatment protocols include surgical excision or a non-invasive option, using botulinum toxin type A (BTX-A). There is no study in the literature that measures this dimensional change in the masseter muscle (MM). The aim of this case report is to present changes in volume and surface area in MM with three-dimensional closer an gestereophotogrammetry (3DCS). For treatment 30 units of BTX-A was injected into the three points hypertrophic muscle and patient records were taken to compare with 3DCS with a non-metric Canon EOS 550 D camera before and after injection. The changes in the surface area and volume of this muscle were mapped and the objective data were obtained. This technique is useful for predicting the results of BTX-A application, and can be a useful tool for better physicianpatient communication.

Evaluation of stress distribution in critical anatomic regions following the Le Fort I osteotomy by three-dimensional finite element analysis.

In this study, we aimed to measure the stresses both on the pterygoid plates and the cranial base during the down-fracture and at the time of pterygomaxillary osteotomy by using the finite element analysis method to have an idea about the possible causes of complications. Three different surgical approaches were applied to the obtained models. In the Model 1, Le Fort I cuts without pterygomaxillary separation was applied. In the Model 2, same standard Le Fort I cuts were applied with pterygomaxillary separation. Then both models were subjected to a force of 150 N over the anterior spina nasalis to simulate down-fracture. In the third model, same standard Le Fort I cuts were applied. Following this procedure, a force of 50 N was applied with a sharp osteotome to the pterygomaxillary junction to simulate osteotomy. According to the results of this experimental study, the cranial base stress values decreased during the down-fracture in the Model 2. Moreover, it was found that the force transmitted to the base of the skull is less when the height of the pterygomaxillary osteotome is limited to 1 cm as we applied in Model 3.

Biomechanical evaluation of hybrid fixation method of sagittal split ramus osteotomy in mandibular advancement.

PURPOSE: In this study, eight different fixation methods applied after sagittal split ramus osteotomy (SSRO) were compared experimentally. MATERIALS AND METHODS: SSRO was performed to 48 sheep hemimandibles in eight groups of 6 each. Group A- a four hole standard miniplate; Group B- a four hole standard miniplate and one bicortical screw; Group C-a four hole locking plate; Group D-a four hole locking plate and one bicortical screw; Group E-a six hole straight miniplate; Group F-a six hole straight miniplate and one bicortical screw; Group G- a sliding plate, which was specifically designed for SSRO; Group H- sliding plate and one bicortical screw. RESULTS: In terms of measured values of displacement, the highest degrees of displacement were observed in decreasing order in Groups G, C, A, and E. The least displacement values were detected in Groups H, F, D and B with values being very close to each other. For linear force applied up to 70N, 3 mm or higher displacement values were not seen in any fixation system. CONCLUSION: According to the results of study, all systems are suitable for clinic usage. However, intermaxillary fixation or functional elastics may be needed for sliding plate systems during the healing period of hard tissue.

Histological evaluation of effectiveness of platelet-rich fibrin on healing of sinus membrane perforations: A preclinical animal study.

The aim of this study was to evaluate the effectiveness of platelet-rich fibrin (PRF) in repairing of Schneiderian membrane perforations in rabbit maxillary sinus. A total of 42 female New Zealand rabbits were randomly divided into two groups. Symmetrical bony defects were created 1 cm in diameter and the sinus membranes were exposed. The Schneiderian membranes were elevated in both sinuses and each membrane was perforated with a 1 cm incision. No treatment was applied to the right perforations in both groups. Left-sided perforations were closed with collagen membrane in the first group and PRF membrane in the other group. Seven animals randomly selected from each group were sacrificed at weeks 1, 2 and 4 in order to be able to examine the amounts of lymphocytes, fibroblasts, veins, and collagen fibers in the area where the membranes were applied. Histological analyses showed that there were no statistically significant differences between the collagen membrane and the PRF membrane in the healing of sinus perforation area. PRF may be considered as an alternative application to collagen membrane in sinus membrane perforations.

Eruption of an impacted canine in an adenomatid odontogenic tumor treated with combined orthodontic and surgical therapy.

An adenomatoid odontogenic tumor is an uncommon asymptomatic lesion that is often misdiagnosed as a dentigerous cyst. It originates from the odontogenic epithelium. Enucleation and curettage is the usual treatment of choice. Marsupialization may be attempted instead of extraction of the impacted tooth, since it provides an opportunity for tooth eruption. This case report is the first to report on the eruption of an impacted canine in an adenomatoid odontogenic tumor treated with combined orthodontics and marsupialization. The impacted canine erupted uneventfully, with no evidence of recurrence 3 years after the treatment.

Biomechanical evaluation of different fixation systems after Le Fort I osteotomy in polyurethane models of unilateral clefts.

We compared the stability of three different titanium plate-and-screw fixation systems after Le Fort I osteotomy in polyurethane models of unilateral clefts. Thirty-six models were divided into 3 groups. In the first group, we adapted standard Plates 1mm thick with 2.0mm screws and placed them bilaterally on the zygomatic buttress and the piriform rim. In the second group, we did the same and added Plates 0.6mm thick with 1.6mm screws between the standard 2mm miniplates on both sides. In the last group, we placed Plates 1.4mm thick with 2.0mm screws bilaterally on the maxillary zygomatic buttress and piriform rim. Each group was tested in the inferosuperior (IS) and anteroposterior (AP) directions with a servo-hydraulic testing unit. In the IS direction, displacement values were not significantly different up to 80N, but between 80 and 210N, those in the 2×1.4mm group were better. In the AP direction, displacement values were not significantly different up to 40N, but between 40 and 180N, they were better in the standard with 1.6×0.6mm group and the 2×1.4mm group. When normal biting forces (90 - 260N) in the postoperative period are considered, the greatest resistance to occlusal loads was seen in the 2×1.4mm group. In the others, the biomechanical properties were better in the AP direction.

Effects of osteoformin in the rapid distraction osteogenesis of rabbit mandibles.

OBJECTIVE: To evaluate the effects of osteoformin on mineralisation and quality of the new bone formation during rapid distraction osteogenesis. METHODS: This multi-centre study was conducted at the Karadeniz Technical University, Middle East Technical University and Selcuk University. The experimental study was conducted from January 2010 to September 2012 and comprised New-Zealand rabbits that were randomly divided into three groups. In group I distraction rate was 1 mm/day while in groups II and III distraction rates were 2mm/day and 1 mm/day. In groups I and II 100µg/kg osteoformin was injected after the latency period. Distraction region was evaluated by radiological, histomorphometrical and dual energy X-ray absorptiometry analyses. SPSS 17 was used for statistical analysis. RESULTS: There were 18 rabbits with each of three groups having 6(33.3%). Accelerated bone healing was noted in groups I and II compared with group III (p<0.05). No significant differences were indicated between groups I and II (p>0.05). CONCLUSIONS: Local injection of osteoformin was effective in the craniomaxillofacial distraction osteogenesis in rabbits. Further experimental studies are recommended before using osteoformin on humans.

Management of central giant cell granuloma of the jaws with intralesional steroid injection and review of the literature.

PURPOSE: We report the results of the intralesional steroid injections for the management of central giant cell granuloma (CGCG) of the jaws. METHODS: Seven CGCGs were treated with intralesional injection of corticosteroids. To accomplish this, 3.5 mL of triamcinolone and 3.5 mL of 0.5 % marcaine with 1/200,000 epinephrine (total 7 mL) were mixed. An adequate amount of steroid was injected into different areas of the lesion. This procedure was repeated on a weekly basis for 6 weeks. RESULTS: Clinical and radiological examination showed complete resolution and ossification of the lesions in four patients. Partial recovery was achieved in two patients. One patient did not respond to the treatment and underwent surgical curettage. CONCLUSIONS: We suggest that intralesional steroid injection is safe and effective for the treatment of CGCG, especially in non-aggressive lesions.

The use of autogeneous mandibular bone block grafts for reconstruction of alveolar defects.

OBJECTIVE: Purpose of this retrospective study was to evaluate outcomes autogenous bone block grafts obtained from mandible for different indications. The healing of the donor and recipient sites in the postoperative period, morbidity and the resorption of the graft were investigated. PATIENTS AND METHODS: Twenty-nine patients grafted with mandibular bone block graft were participated in the present study. Grafting was applied in these patients for three indications; reconstruction of alveolar cleft, lateral crest augmentation before dental implantation and sinus floor augmentation. All operations were performed under local anesthesia and in some cases sedation was used as well. RESULTS: Minimal exposure of the block graft occurred in three alveolar cleft patients. Secondary epithelization was achieved in all cleft patients with no symptoms of infection. In one patient infection was seen in donor site 1-week after the operation. The region was curetted and antibiotics administrated again. Two patients showed an infection of recipient site, after 4 weeks the grafts were removed. In all the patients, as the screw head became apparent until 1 thread, amount of the resorption were considered <1.5 mm. CONCLUSION: The usage of mandibular block grafts is a simple and effective treatment modality for reconstruction of different types of alveolar defects and it also reduces cost of treatment.

Effect of 2 flap designs on postoperative pain and swelling after impacted third molar surgery.

OBJECTIVE: The aim of this study was to evaluate 2 flap designs (envelope and modified triangular flap) for postoperative pain and swelling after mandibular impacted third molar surgery. STUDY DESIGN: Thirty patients who had symmetric bilateral fully impacted mandibular third molars were selected. Left teeth were approached with an envelope flap, and right teeth were removed using a modified triangular flap. Postoperative pain and swelling were evaluated until the seventh day by using 2 verbal rating scales. RESULTS: Statistical analyses showed that there were no significant differences between the 2 incision techniques regarding postoperative pain and swelling (P > .05). CONCLUSIONS: There is no significant difference between the envelope and modified triangular flap regarding postoperative pain and swelling after impacted third molar surgery.

Distracted mandible does not reach the same strength as normal mandible in rabbits.

OBJECTIVE: The aim of this study was to determine the resistance and fracture strength values of the bone with the use of biomechanical tests in different consolidation periods of mandibular distraction osteogenesis. STUDY DESIGN: In this study, 21 mature male New Zeland rabbits were used. After distraction, rabbits were separated into 3 groups to experience 4, 8, and 12 weeks' consolidation periods. Nonoperated hemimandibles of 6 rabbits were used as a control group. After 5 days' latency period, 0.5-mm distraction was applied twice a day, i.e., 1 mm/d lengthening. After the 5-mm lengthening application, we left the animals for 1, 2, or 3 months of consolidation period. Bending stress and strength values of the bone at fracture point were measured with the use of a 3-point bending test. RESULTS: There were significant differences between the control and 3 study groups regarding bending stress and strength values. In addition, each study group was significantly different from each other. CONCLUSIONS: Bending stress and fracture strength of the bone may not reach that of normal bone after completion of 3 months' consolidation. It should be considered to keep in place extraoral appliances or comfortable intraoral distractors for a long period.

Histomorphometric examination of long-term changes in temporomandibular joints after mandibular lengthening by distraction osteogenesis in rabbits.

OBJECTIVE: The purpose of this study was to evaluate long-term histomorphometric changes in temporomandibular joints (TMJs) of rabbits after mandibular distraction osteogenesis (DO). STUDY DESIGN: Twenty-six rabbits were used in this study. Two of them served as control subjects, and the remaining 24 underwent DO procedures in their left mandibular bodies. After a latency period of 5 days, 5 mm lengthening was performed at a rate of 1 mm/d. The rabbits in the experimental group were randomly divided into 4 subgroups and killed after 1, 2, 4, and 6 months. TMJs from both sides were harvested and prepared with hematoxylin and eosin stain for histomorphometric examination under an optical microscope. RESULTS: Compared with control subjects and nondistracted sides, fibrous articular, proliferative, and hypertrophic areas were significantly increased (P < .05) in the first 2 months in distracted sides. The changes were insignificant in the fourth and sixth postoperative months. CONCLUSION: Unilateral mandibular distraction of 5 mm was found to be well tolerated and no degenerative changes were observed histologically in the rabbit TMJs in the long-term period.