Tetsuji Inai

Possible Involvement of Histamine in Muscular Fatigue in Temporomandibular Disorders: Animal and Human Studies

As an approach to clarifying the molecular basis of pain and fatigue in muscles involved in temporomandibular disorders, we examined the activity of histidine decarboxylase (HDC), the enzyme which forms histamine, in the masseter muscles of mice. In the resting muscle, HDC activity was very low. Direct electrical stimulation of the muscle markedly elevated HDC activity. HDC activity rose within 3 hrs of the electrical stimulation, peaked at 6 to 8 hrs, and then gradually declined. Intraperitoneal injection of a small amount of interleukin-1 (IL-1) (from 1 to 10 μg/kg) produced a similar elevation of HDC activity in the masseter muscle. We also examined the effect of an antihistamine, chlorphenylamine (CP), on temporomandibular disorders in humans and compared it with that of an antiinflammatory analgesic, flurbiprofen (FB). Two groups received one or the other of the drugs daily for 7 days, and they were asked about their signs and symptoms before and after the treatment. A positive evaluation of their treatment was made by 74% of the CP group, but by only 48% of the FB group. Although the effects of CP on the limitation of mouth-opening and on joint noise were negligible, about 50% of the CP group answered positively concerning the drugs effect on spontaneous pain or pain induced by chewing or mouth-opening. The positive evaluation for CP (50%) in relieving associated symptoms (headache or shoulder stiffness) was significantly greater than for FB (13%). FB showed effectiveness similar to but sometimes weaker than that of CP on several symptoms. On the basis of these and previous results and the known actions of histamine, we propose that the histamine newly formed following the induction of HDC activity, which is itself mediated by IL-1, may be involved in inducing pain and, possibly, stiffness in muscles in temporomandibular disorders.

Use of an Osseointegrated Implant for Dental Rehabilitation after Cleft Repair by Periosteoplasty: A Case Report

OBJECTIVE We report here on a patient with unilateral cleft lip and alveolus who underwent dental rehabilitation of cleft alveolus using an osseointegrated implant after cleft repair by periosteoplasty. The patient, whose lateral incisor was congenitally missing, had periosteoplasty, followed by excellent bone formation at the cleft alveolus within 2 years. After the completion of orthodontic alignment of the maxillary dental arch, a Brånemark single-tooth implant was placed into the bone-formed alveolus. CONCLUSION This treatment procedure offers an option of dental rehabilitation for the alveolar clefts of patients with cleft lip and/or palate.

Long-term follow-up of dental implants placed in a grafted alveolar cleft: evaluation of alveolar bone height

OBJECTIVE The purpose of this study was to evaluate the long-term follow-up of dental implants placed in the grafted alveoli of patients with cleft lip or palate clinically. PATIENTS AND METHODS Sixteen patients (8 males and 8 females) who had dental implants placed in alveoli grafted using particulate cancellous bone and marrow (PCBM) from the iliac crest were evaluated. The marginal bone level around the implant was evaluated radiologically at 1 (stage I), 3 (stage II), and 6 years (stage III) after connecting the abutment. The interdental alveolar bone height (IABH) was also evaluated radiologically for up to 6 years. RESULTS During the follow-up period of an average of 8.6 +/- 0.6 years (range: 7.2 to 9.4 years), only 2 implants were lost in 1 patient, the cumulative survival rate was 90.9%, and the clinical outcome was uneventful in all implants. The marginal bone levels around the implants were 0.29 +/- 0.18, 0.29 +/- 0.19, and 0.28 +/- 0.15 mm at stages I to III, respectively. Moreover, IABH was reduced only in 2 of 16 (12.5%) of the implant-placed grafted alveoli, and was maintained after implant placement for up to 6 years. CONCLUSIONS These findings indicate that the use of dental implants placed in grafted alveoli is beneficial for maintenance of the grafted bone in patients undergoing secondary bone grafting for cleft repair.

A Mechanism to Diminish the Removable Partial Denture Dynamics.

Excess removable partial denture dynamics during function may cause mechanical trauma on the abutments and the resorption of the residual ridges. A removable partial denture should be stabilized in the spatial position by the compensatory support due to the remaining abutments and the residual ridges. In this study, the mechanism to diminish the removable partial denture dynamics was investigated by annual review of selected dental literature. Rigid bracing of the denture, rather than rigid retention, should be required with the stability of the removable partial denture under the protection of abutments and residual ridges. Rigid bracing of the denture will be obtained through connecting rigidity between abutments and retainers. Great connecting rigidity and bracing are obtained through the guiding surface/guiding plate parallelism between the abutments and retainers. The occlusal force distribution should be controlled by changing the connecting rigidity between abutments and removable partial denture.