A Novel Device for Blood Drainage after Le Fort I Osteotomy: Maxillary Sinus Ventilation Drainage (MSVD).

The purpose of this study is to present a novel maxillary sinus ventilation drainage (MSVD) device which facilitates blood drainage and nasal breathing after Le Fort I osteotomy. One hundred patients who underwent bimaxillary orthognathic surgery from January 2016 to June 2016 at the Department of Oral and Maxillofacial Surgery, Chung-Ang University Hospital were retrospectively selected and divided into two groups. MSVD was applied in 50 patients, who were allocated to the MSVD group, while the remaining 50 patients, in whom MSVD was not applied, were allocated to the non-MSVD group. All patients underwent a cone-beam computed tomography (CBCT) scan before and 2 days after surgery. CBCT was used to analyze middle meatus patency and the percentage of hematoma volume per entire maxillary sinus volume. Statistical comparisons between the two groups were performed using the Chi-squared and Mann-Whitney U tests to investigate the clinical effectiveness of MSVD. The MSVD group showed significantly higher maintenance ratio of the middle meatus patency and a higher percentage of maxillary sinus air volume (p < 0.05) than the non-MSVD group. MSVD facilitated nasal breathing after Le Fort I osteotomy by reducing hematoma inside the maxillary sinus and promoting middle meatal patency.

Effects of pre-extraction intermittent PTH administration on extraction socket healing in bisphosphonate administered ovariectomized rats.

The purpose of this study was to investigate the effect of administering intermittent parathyroid hormone (iPTH) before tooth extraction versus after tooth extraction on the risk of developing MRONJ in experimental animal model. Twenty-five ovariectomized rats received 6 weeks of bisphosphonate therapy. They were classified into 3 groups, based on the timing of the medication, as Control, Pre-PTH and Post-PTH groups. For Control group, normal saline was administered before and after tooth extraction. iPTH was administered during 4 weeks before tooth extraction for Pre-PTH group and after tooth extraction for Post-PTH group. The animals were euthanized 8 weeks after tooth extraction. Macroscopic, histological, micro-computed tomography (micro-CT), and histomorphometric examinations were conducted. The incidences of impaired healing were 11.11% both in Pre-PTH and Post-PTH groups, which was lower than the Control group (42.86%). Bone healing in the extraction socket, based on micro-CT and histomorphometry evaluations, was best in Post-PTH and worst in Control group. The Pre-PTH group showed moderate healing pattern. Despite of limitations in this study, the authors identified Pre-PTH group seems to have positive effect on extraction socket healing. With regard to timing, administering iPTH after tooth extraction was superior to applying it before tooth extraction.

Effect of bisphosphonate on temporomandibular joint in osteopenia-induced rats by botulinum toxin A injection on masticatory muscle: a preliminary study.

BACKGROUND: Botulinum toxin injection on the masticatory muscle induces the osteopenic condition on the ipsilateral condyle. Bisphosphonate suppresses bone resorption and is used to treat osteopenic or osteoporotic condition. This study aimed to evaluate the effect of bisphosphonate administration on prevention of condylar resorption and botulinum toxin A-induced disuse osteopenia in rats. RESULTS: The volume of the condyle and bone volume/tissue volume (BV/TV, %) showed a strong tendency towards statistical significance (p = 0.052 and 0.058). Trabecular thickness (Tb.Th, mm) and trabecular number (Tb.N, 1/mm) were significantly smaller in the Botox group than in the other groups (p < 0.05). The volume of the condyle and BV/TV in the bisphosphonate 100 and bisphosphonate 200 groups showed similar values when compared with the control group. CONCLUSION: Bisphosphonate administration after botulinum toxin A injection in the masticatory muscles appears to prevent condyle resorption and botulinum toxin-induced disuse osteopenia in rats.

The relationship between oral tori and bite force.

OBJECTIVE: The relationship between bite force and torus palatinus or mandibularis remains to be explained. The major aim of this study was to determine the correlation between bite force and oral tori. METHODS: The bite force of 345 patients was measured with a bite force recorder; impressions of the shape and size of the oral tori were taken on plaster models prior to orthodontic treatments. Subsequently, the relationship between oral tori and bite force was analyzed. RESULTS: The size, shape, and incidence of torus palatinus was not significantly correlated with bite force. However, the size of torus mandibularis increased significantly in proportion to the bite force (p = 0.020). The occurrence of different types of oral tori was not correlated with the bite force. DISCUSSION: The size of torus mandibularis provides information about bite force and can thus be used to clinically assess occlusal stress.

Development of animal model for Bisphosphonates-related osteonecrosis of the jaw (BRONJ).

BACKGROUND: The aim of this study is to develop a rat model of bisphosphonates-related osteonecrosis of the jaw (BRONJ) that would be verified with clinical, radiological and histological examination, and to confirm the influence of concurrent bisphosphonates and steroids use upon the occurrence and aggravation of BRONJ. METHODS: Twenty seven rats were divided into 3 groups; Saline group (I), Zoledronate group (II), Zoledronate and Dexamethasone group (III). Rats got weekly intraperitoneal injection for 4 times and extraction of left maxillary and mandibular 1st, 2nd molars were followed. Consecutive injections were performed, and blood sampling for measurements of C-terminal crosslinked telopeptide of type I collagen and tartrate-resistant acid phosphate 5b rats were performed at the time of 2, 4 and 8 weeks. And then, rats were sacrificed and evaluated clinically, radiologically and histologically. RESULTS: 12/18 (66.6 %) of experimental group were diagnosed as BRONJ. There was no significant difference in incidence between zoledronate alone group (ll) and concurrent use of zoledronate and dexamethasone group (lll). CONCLUSIONS: Concurrent use of bisphosphonates and steroids increase incidence of BRONJ compared to saline group (l). Zoledronate alone group (ll) and concurrent use of zoledronate and dexamethasone group (lll) shows same incidence of BRONJ. Based on this study, the rat treated with bisphosphonates and steroids can be considered a novel, reliable and reproducible model to understand pathology of BRONJ.

Mandibular condyle and infratemporal fossa reconstruction using vascularized costochondral and calvarial bone grafts.

There are some difficulties in approaching and removing the lesion in infratemporal fossa because of its anatomical location. After wide excision of tumor lesion, it is also difficult for reconstruction of mandibular condyle and cranium base on infratemporal fossa. Besides, there are some possibilities of cerebrospinal fluid leakage, intracranial infection and bone resorption. It is also challenging for functional reconstruction that allows normal mandibular movement, preventing mandibular condyle from invaginating into the skull. In this report, we present 14-month follow-up results of a patient who had undergone posterior segmental mandibulectomy including condyle and infratemporal calvarial bone and mandible reconstruction with free vascularized costochondral rib and calvarial bone graft to restoration of the temporomandibular joint area.