Masahiko Fukaya

A clinicopathological study of ameloblastomas

72 cases of ameloblastoma were obtained from the files of the Department of Pathology, School of Dentistry, Aichi-Gakuin University for the years January 1970 through December 1983. The cases were analyzed with respect to sex, age, duration, site histopathology, and treatment. Of 72 patients, 63 had no previous therapy, while 9 received their initial treatment elsewhere. There were 38 males and 34 females, a ratio of 1.2: 1. At the time of diagnosis, the ages of all patients ranged from 11 to 71 years, with an average of 36.6 years. About 65% of patients were in the 2nd, 3rd, and 4th decades of life. The duration of symptoms varied from 2 days to 5 years, with an average of 12.6 months. 69 cases occurred in the mandible, with the molar-ramus region being the most frequent site of involvement. Only 3 were found in the maxilla. The left side of the mandible was affected 1.6 times more frequently than the right. Histopathologically, 44 cases were of the plexiform type, 15 the follicular, 10 the acanthomatous, and 2 the basal cell type. Only 1 case was of the granular cell type. Most of the findings in the present study agreed with previous available data from the literature on ameloblastomas.

Verruciform xanthoma of the gingiva: Report of three cases

Forty-seven English and Japanese cases (including three new cases) of verruciform xanthoma of the gingiva were analyzed. Males were affected more frequently than females, and the average age of the patients was 40.9 years. Both maxillary and mandibular gingivae were affected. The most frequent site of involvement in both jaws was the premolarmolar gingiva. Simple surgical excision was the treatment of choice.

Concentrations of Muscle Fiber Type-specific Proteins of Masseter Muscle in Jaw Deformity. Part 1 -Facial Asymmetry.

Facial asymmetry is considered to be caused by the intervention of masticatory muscles, especially the masseter muscle, in some way or another. In skeletal muscles, several proteins, identified immunobiochemically, have been found in specifically high concentrations. A difference in concentration of these muscle proteins in fast-twitch and slow-twitch muscles was found; M-subunit of creatine kinase (CKM) and β-enolase were abundant in fast-twitch muscle, whereas αB-crystallin, S-100a0 and B-subunit of creatine kinase (CKB) were abundant in slow-twitch muscle. In the present study, the masseter muscles of 5 patients with mandibular asymmetry were immunobiochemically analyzed using muscle fiber type-specific proteins.Method: Bilateral masseter muscles of the patients were sampled during orthodontic surgery. All samples were kept frozen at -80°C until analysis.Concentrations of CKM, β-enolase, αB-crystallin, S-100a0 and CKB were determined by the recentlydeveloped sandwitch-type enzyme immunoassay systems. The results showed that the concentration of αB-crystallin and S-100a0 on the deviated side was much higher than on the opposite side. The concentrations of CKM, CKB, and β-enolase were not significantly different.

The effects of laser irradiation on oral precancerous lesions

Recently, some recent cases of malignant transformation after laser therapy for oral precancerous lesions have been reported in the follow-up periods. Thus, the present study attempted to determine the cancer promoting or inhibiting effects of laser irradiation in experimentally-induced oral precancerous lesions. Premalignant lesions were experimentally induced in F344 male rat tongues by 20 ppm 4-nitroquinoline 1-oxide (4NQO) dissolved in their drinking water for 8 weeks. Then, after a 2-week interval, laser vaporizations were performed with a CO2 laser device using non-contact laser, with 6 W power output irradiated for 5 seconds. The rats were divided into 3 groups (untreated, laser vaporization one and three times), and the tongues were excised at 3 days, 1, 2, 4 and 16 weeks after laser vaporization. The early wound healing process following laser vaporization was investigated histopathologically, and cell proliferation in normal and premalignant lesions was assessed using BrdU and GST-P immunohistochemically. The incidence of neoplasms was investigated histopathologically to observe the long-term wound healing process. In the early tissue repair following laser vaporization, although there was no difference in the wound healing process involving loss of epithelium, inflammatory cell infiltration, granulation tissue formation and epithelialization, the wound healing in precancerous lesions tended to take longer. Also, the survival premalignant epitheliums showing GST-P positive staining and the epitheliums regenerated from those portions were observed. Moreover, the BrdUlabeling index of the regenerated epitheliums showing GST-P negative staining (i.e., normal) at first indicated temporary cell growth, and a decrease 2 weeks later. However, the cell growth of the regenerated epitheliums in premalignant portions showing GST-P positive staining was lower than that with GST-P negative staining and tended to take longer. In the long-term wound healing process after laser vaporization, a decrease in the incidence of neoplasms was observed in the laser vaporization groups, suggesting a decrease in the number of premalignant lesions. However, the depth of invasion and tumor area were enhanced. Repetitive laser vaporization also caused a progression. On the basis of the above-mentioned findings, when oral precancerous lesions were not completely removed by laser vaporization, it was suggested that there was a risk of cancer promotion from the surviving epitheliums. I.緒 言 口腔前癌病変への レーザー治療 に関 しての臨 床報告で,レ ーザー照射後に癌化 を来 た した症 例 を報告す るものも散見 され るよ うにな り,口 腔前癌病変 に対する レーザー照射療法 と悪性化 との関係が 問題視 されるようになって きた1)2). 今 日まで,口 腔前癌病変 に対する レーザ ー照射 の影響 についての基礎的研究は数少な く,レ ー ザ ー照射による発癌への促進の可 能性 お よびそ の作用 について は不 明な点が多い.本 研 究では, ラ ッ ト舌に実験 的口腔前 癌病変を作製 し,レ ー ザ ー蒸散後の前癌病変部 における創傷 治癒過程

Epidemiologic Survey of the Patients with Dento-facial Deformity. Questionnarie Study.

Epidemiologic study was conducted bygiving a questionnaire to 414 patients (128 males, 286 females) who indicated surgical correction of dentofacial deformity to investigate etiologic factors. The same questionnaire was given to 482 dental students as the control group and statistically compared with the patient group. The results were as follows:1. The suggestive items of hereditary factors were recognized in the patient group, and many parents, brothers, and sisters of patients tended to have dento-facial deformity and familial congenital anomaly.2. Many patients tended to have suffered from abnormality in their mothers body during fetal stage and birth.3. Many patients tended to have any abnomality of skull morphology during childhood.4. There was no significance of facial traumatic anamnesis between patient and control groups.5. Patients who had many dental caries, oral habits, food preference, underwent orthodontic treatment or operation of jaw during childhood, and anamnesis of temporomandibular joint luxation were significantly more than those in the control group.The results of this study revealed that dento-facial deformity was caused by hereditary and environmental factors

The Influence of Low Power Laser Local Irradiation on the Mineralization of Tooth Germ in Mice

To elucidate the in vivo effect of low power diode laser irradiation on mineralization in molar tooth germ, we examined the effect of the laser on the development of mandibular first and second molars in neonatal mouse. In a newborn mouse, the mandibular first molar showed differentiated odontoblast, differentiated ameloblast, slight dentin and enamel formation. The second molar was an early bell stage. In a two day-old neonatal mouse, the developmental stage of the second molar corresponded to the stage of the first molar in a newborn mouse. The laser (50mW, 5min/day) was irradiated to the mandibular tooth germ at twice and the chemical and histological changes in these molars were examined. In the second molar showing an early developmental stage (cell proliferation and differentiation), the laser irradiation increased alkaline phosphatase activity, calcium content and the formation of both dentin and enamel. Also, in the first molar showing a late developmental stage (additional mineralization), the laser irradiation also increased the mineralization in both dentin and enamel. From the in vivo experiment, we confirmed that diode laser irradiation accelerated tooth formation and mineralization at all developmental stages observed in the present study.(J. Jpn. Soc. Laser Dent. 7: 22-29, 1996 Reprint requests to Dr. Okumura)

The Clinical Study of Low Power Laser Treatment for the Patients of Temporomandibular Joint Disorder

Acupuncture to the meridian point of “Gekan” has been used to treat the patients of temporomandibular joint disorder. In recent studies (Arao et al 1990, 1991, 1992, 1994), instead of using a needle, the author irradiated several times with a low power laser (Nd: YAG at 350mW) for the Type I, Type II and Type III patients with closed-lock. This relieved the pain somewhat, but since the treatment results were determined by the subjective judgement of the patient, the authors evaluated the results objectively. We used thermography to evaluate symptomatic change, and using the Laser Doppler Flowmeter (LDF), we measured the surface blood flow of the skin in the area of the temporomandibular joint.In this study, for the Type IV patients, we used the low power laser. Each patient was treated by low power laser for “Gekan” for 15 minutes from the first examination. After the pain of the temporomandibular region was remedied, we manipulated the mandible. The results were that in several months, the symptoms of temporomandibular disorder ceased. But from the MRI findings, the disk position and the shape of mandibular head did not change.These results suggest that the low power laser treatment for the patients of temporomandibular joint disorder is useful not only for the Type I, Type II, Type III parients with closed-lock patients, but also for Type IV patients.We suggest that it is necessary to continue this line of research for a long period, and to treat a greater number of cases.(J. Jpn. Soc. Laser Dent. 7: 72-82, 1996 Reprint requests to Dr. Arao)

The Effect of Low-Power Laser Irradiation

We postulated that low-power laser irradiation could produce analgesia, nerv ous activation, and enhancement of wound healing in association with changes in the microcirculation. In order to confirm this hypothesis, we monitored blood flow in rats be fore and after laser treatment. A Ga-Al-As semiconductor laser (wave length: 810nm) was used. Rats were treated at either (1) 300mW×3min, (2) 500mW×3min, (3) 700mW×3min, (4) 300mW×20min, (5) 500mW×20min, or (6) 700mW×20min. Blood flow was monitored in the dorsal skin before and after irradiation using a Laser-Doppler flowmeter. The peripheral circu lation was improved by 20min of irradiation with a 300mW or 500mW semiconductor laser without any irreversible tissue damage, and it was inferred that tissue restoration would result from this change. Different responses were produced depending on the irradiation condi tions, and this suggested that there is a safe range between transition from non effective to effective and from effective to irreversible damage. This range was considered to be the saf est and most effective for low-power laser treatment.

The Healing Process of the Rats Tongue After Nd: YAG Contact Laser Irradiation

The purpose of this study was to examine the healing process of the tongue wounds caused by the Nd: YAG contact laser.SEM was used, focusing mainly on the dermal papillae, and the results were compared with the healing process of the wound by a dental bar.In the case of the laser group, on the 4th day, the wound was filled with connective tissue. On the 7th day, regenerating dermal papillae were observed at the edge of the wound. On the 28th day, the wound healed, but the dermal papillae looked like mountains.In the case of the control group, on the 7th day, regenerating dermal papillae were observed over the entire surface of the wound. Their papillae in the center of the wound were morphologically different from the original ones.

Effects of Low Power Laser Irradiation on the Mineralization of Tooth Germ in Mice

The effect of low power laser (diode laser) irradiation on the mineralizationand alkaline phosphatase activity in the tooth germ was examined.Mandibular first molarsfrom 17-day-old mouse embryos were cultured with or without low power laser irradiation (the irradiation time were 0, 1, 3 or 5 minutes per day). The calcium content and alkalinephosphatase activity in the tooth germ increased gradually from 0 to 7 days in culture, theincrease of calcium content being preceded by that of alkaline phosphatase activity. The irradiation by low power laser (5 minutes) increased the alkaline phosphatase activity in thetooth germ cultured for 3 days, without affecting the calcium content. There was no increaseof alkaline phosphatase activity in the tooth germ cultured and irradiated with low powerlaser for 7 days. However the irradiation by low power laser (5 minutes) increased calciumcontent in the tooth germ.These results suggest that low power laser irradiation may accelerate the mineralizationstage of the tooth germ. For evaluating the action on mineralization in the tooth germ, irradiation of 5 minutes per day was optimal. (J. Jpn. Soc. Laser Dent. 4: 27-31, 1993 Reprint requests to Dr. Arakawa)