Today, CT is one of the most important methods of radiological examinations in dentistry. The clinical application of CT starts from the field of oral surgery in the diagnosis of tumorous lesions. Medical CT scanners were large and expensive systems designed for whole-body scanning at a high speed. They were not suited for dentistry, where cost considerations were important, space was often at a premium, and scanning requirements were limited to the head. The advent of arm-type cone beam CT（CBCT） has paved the way for the general dentist to own CT. Moreover, clinical application of surgical simulation and navigation system with 3D CT imaging is getting popular. However in compare with medical whole-body C T, dental CBC T has several disadvantages in the characteristics of density resolution. These are projection data discontinuity related artifact, x-ray beam hardening phenomenon, halation of x-ray detector, and so on. Development of high-speed photon counter type detector based small and inexpensive dental CT scanners has been eagerly anticipated.
Metal allergy has been considered one of the main causes of oral lichen planus (OLP) and palmoplantar pustulosis (PPP). However, the details remain poorly understood and controversial. The aim of this study was to reveal the association between these diseases and dental metal allergy. Forty patients with OLP and 67 with PPP who presented at our clinic from 1992 through 2008 were studied. The presence of metal allergy confirmed by patch testing according to the ICDRG criteria. The positive rate was 45.0％ (18 of 40) in OLP and 46.3％ (31 of 67) in PPP. The rate of symptom improvement after removal of dental metal was significantly higher in PPP than in OLP (P<0.05). In PPP, symptom improvement in patients with flare-up on patch testing was significantly better after removing dental metal than that in patients without flare-up phenomenon (P<0.05). These results suggest that PPP might be more closely related to dental metal allergy than OLP. In addition, removal of dental metal is demonstrated to be useful in PPP patients with flare-up.
Traumatic internal carotid artery obstruction developing after maxillofacial trauma is difficult to diagnose. We report the case of 16-year-old woman with traumatic internal carotid artery obstruction following a mandibular fracture. She was hospitalized for a mandibular fracture after getting involved in a traffic accident. Although her condition was satisfactory immediately after hospitalization, she suddenly developed disturbed consciousness and exhibited symptoms of left-sided paralysis 12 hours after injury. Magnetic resonance angiography (MRA) revealed obstruction of the internal carotid and middle cerebral arteries on the right side. She was transferred to an emergency care center 15 hours after injury and underwent thrombectomy and hemostasis for cerebral hemorrhe. The mandibular fracture was monitored given her unstable physical condition and signs of restlessness accompanying disturbed consciousness. She recovered fully without any pronounced dysfunction or cosmetic disturbance. This case shows that traumatic injury resulting in cervical hyperextension or hyperflexion can cause internal carotid artery obstruction. These findings underscore the importance of careful follow-up in patients with mandibular fracture, regardless of whether they present with apparent head injury, given the possibility of traumatic internal carotid artery obstruction.
Metastatic calcification (MC) is a complication in patients undergoing hemodialysis, but MC in oral lesions is rare. We report a 49-year-old woman who had undergone hemodialysis for autosomal dominant polycystic kidney disease (ADPKD) with MC arising in the maxilla. The patient had received hemodialysis for the treatment of hyperphosphatemia associated with ADPKD. She visited our hospital for examination of the lower mandible on the left side. No abnormalities were present, except slight buccal expansion in the left upper premolar region. Panoramic X-ray examination revealed a wellcircumscribed and internally heterolytic radiopacity in the upper alveolar region. Under the clinical diagnosis of complex odontoma, the lesion in the upper alveolar region was resected. The lesion consisted of several hard yellowish masses that were encapsulated by a thin layer of fibrous tissue. Histopathological examination of the decalcified specimens of the resected tissue revealed dense capsular fibrous connective tissue including several irregularly shaped calcified tissue masses. There was also a focus of strongly basophilic material showing small particles and a laminated or amorphous structure, with no apparent formation of dentin. These findings suggested metastatic calcification. There was no sign of recurrence during 6 years of follow-up.
The Stickler syndrome (STL) is an autosomal dominant inherited disease caused by mutation of the collagen genes and is classified into STL1, STL2, and STL3. It is associated with eye manifestations, such as progressive myopia and retinal detachment, hypoplasia of the face, cleft palate, microgenia, and epiphyseal dysplasia. Patients with STL consult oral surgeons because of conditions such as cleft palate and microgenia in an early stage in many cases, but the rate of diagnosis is low. Late diagnosis of STL1 and STL2 can lead to aggravation of eye manifestations, potentially causing loss of eyesight. Therefore, dentists need to thoroughly understand this syndrome. We report four cases of STL. The patients presented at Tokyo Dental College Hospital for the treatment of cleft palate, immediately after birth. All patients had microgenia, face midline hypoplasia, detachment between eyes, and extreme myopia. Their families had eye diseases such as nearsightedness and cataracts and therefore consulted pediatricians. The pediatricians found epiphyseal dysplasia an X-ray films of the pelvis and knee, and STL was diagnosed. Moreover, gene analysis revealed mutation at COL2A1 in two cases, and mutation at COL11A2 was suggested in another case. Since these patients were treated in departments of pediatrics and ophthalmology at an early stage, eye condition is stable. When examining patients with cleft palate it is necessary to keep in mind the possibility of SLT while assessing other clinical findings.
We report a rare case of intraosseous schwannoma in the mandible. The tumor was an elastic hard mass, associated with resorption of the mandible in the left second premolar region. The surgically removed tumor was a partially uncapsulated mass measuring 10 × 13 × 14mm in diameter. Histopathologically, the tumor showed typical features of Antoni type A schwannoma. Schwannoma is an encapsulated benign tumor originating from Schwann's cells of the neural sheath. It rarely occurs in the maxillofacial region, and uncapsulated intraosseous schwannomas involving the jaw are extremely rare. This article reviews and summarizes the mechanism and capsule loss of intraosseous schwannoma according to the literature.