Michel Campos Ribeiro

Bite force, electromyography, and mandible mobility during the 6-month period after surgical treatment for isolated fractures of the zygomatico-orbital complex

OBJECTIVE The aim of this study was to identify the behavior of masticatory muscles after fractures of the zygomatico-orbital complex (ZOC) and subsequent surgical treatment, by using analyses of bite force, electromyography (EMG), and mandible mobility during a 6-month period after surgery. STUDY DESIGN Five patients with fractured ZOCs treated surgically by using an intraoral approach and fixation exclusively in the region of the zygomaticomaxillary buttress were evaluated. The control group included 12 other patients. During postoperative follow-up, bite force, mandible mobility, and EMG analysis of the masticatory muscles were evaluated. RESULTS There was an increase in bite force with time, but a decline in EMG activity during the same period. In the mandible mobility analysis, only maximum mouth-opening values increased significantly after the surgical treatment. CONCLUSIONS The masticatory musculature, according to bite force and EMG, returned to its normal condition by the second month after surgery, and maximum mouth opening was observed after the first month.

Evaluation of in vitro resistance of titanium and resorbable (poly-L-DL-lactic acid) fixation systems on the mandibular angle fracture.

The purpose of this study was to compare, by mechanical in vitro testing, a 2.0-mm system made with poly-L-DL-lactide acid with an analogue titanium-based system. Mandible replicas were used as a substrate and uniformly sectioned on the left mandibular angle. The 4-hole plates were adapted and stabilized passively in the same site in both groups using four screws, 6.0mm long. During the resistance-to-load test, the force was applied perpendicular to the occlusal plane at three different points: first molar at the plated side; first molar at the contralateral side; and between the central incisors. At 1mm of displacement, no statistically significant difference was found. At 2mm displacement, a statistically significant difference was observed when an unfavourable fracture was simulated and the load was applied in the contralateral first molar and when a favourable fracture was simulated and the load was applied between the central incisors. At the failure displacement, a statistically significant difference was observed only when the favourable fracture was simulated and the load was applied on the first molar at the plated side. In conclusion, despite more failure, the poly-L-DL-lactic acid-based system was effective.

Osteopetrosis Complicated by Osteomyelitis of the Maxilla and Mandible: Light and Electron Microscopic Findings

This report presents a case of osteopetrosis in a 25-year-old male, which was complicated by the development of osteomyelitis in the maxilla and mandible following traumatic injury and tooth extractions. The osteomyelitis in the mandible was refractory to marginal resection and antibiotic therapy. Partial resection with mandible reconstruction was then carried out. Light and backscattered electron scanning microscopy revealed sclerosis of spongy bone and variations in mineral density of the bone matrix. There was also a prominent periosteal bone formation in regions affected by osteomyelitis. An 18-month follow-up showed absence of active infections in the face and oral structures, with a focal area of bone exposure in the right parasymphysis. However, development of anemia and bone marrow deficiency will likely affect prognosis. The importance of preventive oral health care and dental/periodontal managements in osteopetrosis is emphasized.

Clinical, microscopic and imaging findings associated to McCune-Albright syndrome: report of two cases.

McCune-Albright syndrome is characterized by the triad café-au-lait cutaneous spots, polyostotic fibrous dysplasia and endocrinopathies. This article presents two cases of McCune-Albright syndrome in a middle-aged woman and a young girl. Both patients presented café-au-lait spots on the face and other parts of the body and expansion of the mandible with radiopaque-radiolucent areas with ground-glass radiographic appearance, and were diagnosed as having fibrous dysplasia and endocrine disorders. The patient of Case 1 had fibrous dysplasia on the upper and lower limbs, thorax, face and cranium, early puberty, hyperglycemia, hyperthyroidism and high serum alkaline phosphatase levels. The patient of Case 2 presented lesions on the upper limbs and evident endocrine disorders. In both cases presented in this article, the initial exam was made because of the mandibular lesion. However, a diagnosis of fibrous dysplasia must lead to investigation of the involvement of other bones, characterizing polyostotic fibrous dysplasia, which is manifested in a number of diseases. An accurate differential diagnosis is mandatory to determine the best treatment approach for each case.

Oral myiasis in an elderly patient

BACKGROUND Myiasis is the invasion of living tissue of humans and other mammals by eggs or maggots of flies of the order of Diptera. It occurs mainly in the Tropics and is associated with inadequate public and personal hygiene. Oral myiases in an older man appears to be rare. OBJECTIVE To relate a case of oral myiases in a debilitated older man treated by mechanical removal of the maggots, identifying the adult insect that caused the infestation. METHODS The diagnosis of oral myiasis was established by the clinical examination and it was detected that the infestation involved only soft tissue and the sinus cavity. The patient was submitted to two mechanical removal of the visible maggots. RESULTS Total of 110 maggots was removed from the oral cavity of the patient and adult insects was identified as belonging to the Calliphoridae Family, Cochliomyia hominivorax species. The patient died two days after the second procedure by severe systemic complications. CONCLUSIONS The mechanic removal and the identification of the maggots must be adopted as soon as possible to prevent further tissue damage and bacterial infection in cases of oral myiasis. Special attention should be given to the debilitated old patients that are particularly susceptible to oral myiasis infestation.

Focal osteoporotic bone marrow defect mimicking a mandibular cystic lesion.

An unusual presentation of a focal osteoporotic bone marrow defect (FOBMD) of the mandible mimicking a cystic lesion is documented. A definitive diagnosis could be established only on the basis of the histopathologic evaluation. A 66-year-old Brazilian woman was referred by her dentist for well-defined radiolucency of the mandibular molar region suggesting a cystic lesion of odontogenic origin. The computed tomography scan confirmed that the lesion did not affect the corticals. The biopsy confirmed the diagnosis of FOBMD. The diagnostic difficulty in the current case is obvious, because FOBMD, usually exhibiting an ill-defined radiolucency, is seldom suspected preoperatively when a differential diagnosis is considered for focal well-defined radiolucent areas in the jaws.

In vitro evaluation of the resistance of a 2.0-mm titanium fixation system in the sectioned angle without continuity of the inferior border of the mandible.

The aim of this in vitro study was to evaluate the mechanical resistance of a 2.0-mm titanium system applied to the mandibular angle, either with or without continuity of the inferior border of the mandible. Polyurethane mandibles were used as substrates and divided into two groups: unfavourable and favourable to treatment. A single cut was made through the retromolar region, simulating an angle fracture either unfavourable or favourable to treatment. In addition, a small fragment of the inferior border of the mandible was removed in some of the mandibles, creating a discontinuity. The fragments were stabilized in accordance with the technique of Champy et al. The substrates were adapted to a universal mechanical testing machine and submitted to a constant load applied at three different points; load values were obtained at three different moments of displacement: 1mm, 2mm, and fixation failure. The value of the tip dislocation at final displacement was obtained. When the load was applied at the first molars, regardless of the side, no statistically significant difference was observed between the groups. When the load was applied at the central incisors, a statistically significant difference was observed at fixation failure in the unfavourable to treatment group, with better results in the subgroup with continuity of the inferior border of the mandible compared to the subgroup without continuity. Discontinuity of the inferior border of the mandible did not decrease the mechanical resistance of the fixation.