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.

Compartment Syndrome of the Temporal Muscle.

The authors report a patient with masticator space abscess due to an ascending infection following a wisdom tooth extraction. They administered antibiotics and did an incision and drainage; however, osteomyelitis of the mandible and compartment syndrome of the temporal muscle complicated the course. The authors suggest a physiopathology and discuss the management of this study.

Effects of metabolic syndrome on jawbones and bone metabolic markers in sucrose-fed rats.

The aim of this study was to investigate the effects of metabolic syndrome (MetS) on bone mineral density (BMD) and microstructure of jawbones, and circulating bone metabolic markers. MetS was induced in male Wistar rats by a 16-week high-sucrose drinking water diet. Mandibles were analyzed for BMD and microstructure by standard radiographs and X-ray diffraction. BMD of three different regions of mandible in MetS group was significantly lower compared to control group. The diffraction intensity of mandibular bone in MetS group was significantly decreased (8.2%) compared to control group; however, crystallite radiuses of mandibular bone samples in both groups were not significantly different. In MetS group, serum bone-specific tartrate-resistant acid phosphatase-5b (TRACP-5b) activity was significantly increased (47%), whereas bone-specific alkaline phosphatase (BALP) activity was significantly decreased (44%) compared to control group. The serum magnesium level in MetS rats (1.82 ± 0.27 mg dL-1) was lower than that of controls (2.11 ± 0.16 mg dL-1). Rats with MetS had significantly higher serum calcium level (9.70 ± 0.41 mg dL-1) than the controls (9.21 ± 0.50 mg dL-1). Overall data suggested that MetS is associated with a significant decrease in BMD and slight deterioration in microcrystallite structure of the jawbones. The changes in TRACP-5b and BALP activities and serum Ca2+ and Mg2+ concentrations also support these findings at a biochemical level.

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.

Is it necessary to alter anticoagulation therapy for tooth extraction in patients taking direct oral anticoagulants?

Background: The number of patients using direct oral anticoagulants (DOACs) instead of vitamin K antagonists (VKA) is increasing and there is limited data on the safety of tooth extractions in patients taking DOACs. The aim of this study was to compare the amount of bleeding (AOB) and postoperative complications after tooth extractions between patients taking VKAs and patients taking DOACs without altering the anticoaguation therapy. Material and Methods: The study consisted of four groups: Direct thrombin inhibitor group, factor Xa inhibitor group, warfarin group and a control group. A single tooth was extracted in each patient and routine coagulation test values were recorded prior to extraction. AOB was measured for 20 minutes after tooth extraction. The patients were evaluated on 2nd and 7th days after extraction for bleeding. Status of bleeding was classified as no bleeding, mild bleeding controlled by gauze pads, moderate bleeding controlled by hemostatic agents and severe bleeding required hospitalization. Analysis of variance, chi square test and correlation analysis were used for statistical analysis of data. Results: A total of 84 patients (48 male, 36 female) were included in this study. The mean age of patients was 57 (38-87) years. Mean AOB was 1388.6±913.0, 1909.29±1063.1, 3673±1415.4, 1593.33±672.5 mg for direct thrombin inhibitor, factor Xa inhibitor, warfarin and control groups respectively. Mean AOB was significantly higher for warfarin group, compared to other groups (p=0.001). No bleeding was occurred in control group on 2nd and 7th postextraction days and no bleeding was occurred in direct thrombin inhibitor group on 7th postextraction day. The number of bleeding events among groups was not statistically significant on 7th postextraction day (p=0.251). Conclusions: Patients taking warfarin had more bleeding compared to patients taking direct oral anticoagulants after tooth extractions. In patients taking direct oral anticoagulants simple tooth extractions can be safely carried out without altering the anticaogulant regimen with the use of local hemostatic agents (AU)

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