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Biomedical subjects

Hideharu Yamaguchi

Publications and source records attributed to Hideharu Yamaguchi.

At least 19 recordsLinked to original sources

Cephalometric study of elderly with nearly intact dental arches.

OBJECTIVE: The purpose of this study was to investigate the craniofacial morphology of elderly people with many remaining teeth using cephalometric analysis. SUBJECTS AND METHODS: The subjects were 30 Japanese elderly who participated in the '8020 campaign 2001' in Bunkyo Ward, Tokyo, organised by The Dental Association of Tokyo, as well as 30 Japanese young adults with normal occlusion. Lateral cephalograms of all subjects were analysed using the Coben method. RESULTS: In the female elderly group, the lower face depth was smaller than in the younger adults. In the male elderly group, the height and depth of both the total face and the lower face were longer than in the younger group. In comparing the 8020 achievers with the younger group, the proportion of the lower facial height was greater than the upper facial height, and this finding was more pronounced in women than in men. CONCLUSION: For the lateral facial pattern of the elderly, a reduction of lower facial height because of tooth occlusal reduction was not apparent. It was clear that there are age differences for males and females; in addition, differences in the total face and lower face area of the elderly group were due to their having many remaining teeth over a long time period. Also, these changes were more apparent in women than in men, and it is clear that there is a male-female difference in ageing.

Age Factors↗

Oral flora in independent over 80-year-olds with more than 20 teeth.

The purpose of this study was to investigate oral flora in independent persons aged over 80 years with more than 20 remaining teeth. The subjects were 22 participants of the 8020 campaign (6 males and 16 females) with a mean age of 81.3+/-1.6 years and an average of 24.7 teeth (Independent 8020 group). This group was compared with a group of 38 elderly people residing in nursing homes (10 males and 28 females) who had a mean age of 81.3+/-8.5 years and an average of 4.2 teeth (Nursing group with fewer teeth). Saliva samples were collected from the vestibular areas of the maxilla and mandible using cotton swabs. Cell numbers of microorganisms were expressed as colony forming units/ml (CFUs/ml) and compared between the two groups. The average number of Staphylococcus species was 65.2+/-74.4 CFUs/ml in the Independent 8020 group and 400.3+/-352.1 CFUs/ml in the group with fewer teeth (p<0.01); that of Candida albicans was 18.0+/-37.7 CFUs/ml in the Independent 8020 group and 152.9+/-211.9 CFUs/ml in the Nursing group with fewer teeth (p<0.05). Both species showed statistically significant differences between the two groups. This suggests that the Independent 8020 achiever group had better oral hygiene and that the presence of many teeth may be associated with an increased awareness of dental health.

Activities of Daily Living↗

Two cases with supernumerary teeth in lower incisor region.

Abnormalities in number of teeth are occasionally noted in clinical cases. Many theories have been proposed as regards the causes of the occurrence of supernumerary teeth, including atavism theory, mechanical tooth germ separation theory, tissue induction theory, and dental laminar morphological disturbance theory. However, none of these theories alone offers a sufficient explanation for this phenomenon. The incidence of supernumerary permanent teeth is approximately 1-3%. These are the maxillary anterior teeth, the maxillary molars, and the maxillo-mandibular premolars in terms of descending order of site of occurrence. On the other hand, incidence in the mandibular anterior tooth area, of which there have been few detailed reports, is about 0.01%, a markedly low value. In this paper, we report two rare cases of supernumerary teeth in the mandibular incisor area. We discuss their etiology and orthodontic treatment, and detail a differential diagnosis between the normal and supernumerary teeth. We found that it was difficult to establish a clear etiology and differentiation between the normal and supernumerary teeth.

Adolescent↗

Multidisciplinary treatment of mandibular prognathism with multiple congenitally missing teeth.

Surgical orthodontic treatment and dental implant therapy were performed on a man (aged 18 years 8 months) with mandibular prognathism and seven congenitally missing teeth: upper canines, first and second premolars and lower right second premolar. After 17 months of preoperative orthodontic treatment at age 20 years 1 month, sagittal split ramus osteotomy was performed using the remaining upper deciduous teeth as an anchor for intermaxillary fixation. In postoperative orthodontic treatment, the remaining deciduous teeth were extracted, and fixture installation was performed. The entire therapy required 4 years to complete (age 22 years 8 months). After completion of orthodontic treatment, superstructures were put in place. This patient had many dental problems, so multidisciplinary care was performed in conjunction with other departments to improve oral function and facial esthetics.

Adolescent↗

A study of occlusion in elderly Japanese over 80 years with at least 20 teeth.

OBJECTIVES: The purpose of this study was to identify the occlusal status of elderly Japanese over 80 years with at least 20 teeth. MATERIALS AND METHODS: The study enrolled 76 elderly Japanese (44 male, 32 female) with a mean age of 82 years and an average of 25.7 remaining teeth. The study consisted of intra-oral examination, intra-oral and facial photographs, radiographs and impressions for study casts. RESULTS: No gender difference was observed in age or number of remaining teeth. Anteroposterior occlusal relationship was characterised by maxillary protrusion in 67.6%, acceptable overjet in 31.0%, and anterior crossbite in 1.4%. Vertically, deep bite was noted in 33.8%, acceptable overbite in 64.8%, and open bite in 1.4%. Most of the subjects had either Angle class I (68.4%) or class II (25.7%) canine relationship. Only 3.9% of the subjects had upper anterior crowding. Lower anterior crowding was observed in 23.7%, but tended not to be severe. CONCLUSION: These results indicate that Japanese who attained the goal of '8020' have a relatively good occlusion.

Age Factors↗

Evaluation of the implantation position of mini-screws for orthodontic treatment in the maxillary molar area by a micro CT.

The interalveolar septum between the upper first molar and the second premolar of the separated human maxillary bone was three-dimensionally observed by micro CT to evaluate the appropriate mini-screw type implant placement position by considering the relationship between the tooth roots and the maxillary sinus. After taking micro CTs of 5 human maxillary bones, horizontally sectioned images of the interalveolar septum area 2, 4, 6, 8, 10, and 12 mm deep from the crest of the alveolar ridge were reconstructed by three-dimensional reconstruction software. The bucco-lingual and mesio-distal lengths and area in each sectioned interalveolar septum were measured using digital image measurement software. Using the results, the interalveolar septum area between the upper first molar and the second premolar approximately 6-8 mm deep from the alveolar crest in the tooth root apical direction was determined to be the safest position for mini-screw implantation. Furthermore, lateral implantation from the palatal side was deduced to be the safest approach.

Alveolar Process↗

A case of Antley-Bixler syndrome with severe skeletal Cl. III malocclusion.

Antley-Bixler syndrome is a disorder characterized by craniosynostosis, midface hypoplasia, choana blockade, and radiohumeral synostosis. However, the features of occlusion remain unclear. In this paper, we report a case of Antley-Bixler syndrome, a 7-year-old boy, from the viewpoint of orthodontics. From lateral cephalometric head film analysis, remarkable retardation of the anterior subcranial base, infraorbitale, and maxilla were notable, as was vertical growth restriction of the maxilla. The choana blockade tendency was also recognized. Moreover, although reverse occlusion was present, a mandibular retrognathic tendency was also present, and a short ramus mandible, remarkable mandibular vertical growth pattern, and skeletal open bite were present. In the dentition, two of the lower incisors were missing, and the present lower incisors were large. Maxillary and mandibular first molars were delayed in eruption. For treatment, the solutions to such remarkable skeletal problems were limited by the insufficiency of recovery of cranial formation after the operation. We planned a non-surgical treatment to expand the maxilla. It will be necessary to continually consider the treatment of his malocclusion as he continues to grow.

Abnormalities, Multiple↗

Health-related quality of life and psychosocial function 5 years after orthognathic surgery.

This prospective, multisite, randomized clinical trial evaluated the long-term health-related quality of life and psychosocial function of 93 patients after bilateral sagittal split osteotomy to correct Class II malocclusion. Patients were evaluated approximately 2 weeks before surgery, and 2 and 5 years after surgery. Scores from the Sickness Impact Profile psychosocial dimension and all of its components showed significant improvement from presurgery to 2 and 5 years postsurgery (P <.05). The overall dimension score also showed significant improvement (P <.05). Change between 2 and 5 years postsurgery was not significant, demonstrating that the improvement was stable between 2 and 5 years. The Oral Health Status Questionnaire showed significant improvement at 2 and 5 years relative to presurgery (P <.05). These improvements also remained stable between 2 and 5 years, with the exception of general oral health. The Symptom Checklist 90 Revised demonstrated significant improvements from presurgery to 2 and 5 years after surgery (P <.05) in all areas except somatization. Results other than somatization did not change significantly between 2 and 5 years, showing that improvements were stable. The 7-point satisfaction scale showed that patients were satisfied with postsurgical results, and their satisfaction was maintained 5 years after surgery. It is concluded that general health-related quality of life, oral health-related quality of life, and psychosocial function show significant improvements after bilateral sagittal split osteotomy, and the improvements are stable between 2 and 5 years after surgery.

Adolescent↗

A cineradiographic study of deglutitive tongue movement in patients with anterior open bite.

The purpose of this study was to use cineradiographic images to investigate tongue movement during deglutition in anterior open bite patients with tongue thrust. Each subject had semi-spherical lead markers attached to the tip and dorsal surface of the tongue and was asked to swallow 5 ml of diluted liquid barium. Tongue movement during deglutition was recorded in the mid-sagittal plane with an X-ray VTR system. The deglutition process was divided into 6 stages to analyze the movements of the tip and dorsal surface of the tongue in each stage. In open bite patients, both the tip and dorsum of the tongue were positioned anteriorly and inferiorly at rest and during the buildup of negative intraoral pressure. The dorsum of the tongue tended to move and be positioned anteriorly as the tongue tip protruded and pushed the maxillary and mandibular anterior teeth. The tongue tip traveled a significantly smaller distance from the stage of tongue rest position to that of most retruded tongue tip position and a significantly larger distance from the stage of most retruded tongue tip position to that of tongue tip fixation in open bite patients than in controls.

Adolescent↗

Oral habits of temporomandibular disorder patients with malocclusion.

The purpose of this study was to clarify the relationship between oral habits and symptoms of temporomandibular joint disorder in patients who had sought orthodontic treatment by analyzing their present and past history. The subjects were 57 female patients (average age: 23 years and 6 months old) who had visited the "Temporomandibular Disorder Section" in our orthodontic department. Their chief complaints were the symptom of TMJ and the abnormalities of occlusion such as maxillary protrusion, open bite, crowding, mandibular protrusion, cross bite, deep bite, edge-to-edge bite, and spacing. Their present conditions and past histories were examined and evaluated. The most typical primary symptom was joint sound (23 patients, 40.0%). The second was joint sound and pain (15 patients, 26.3%). Of the symptoms present at the time of examination, the most prevalent were joint sound and pain (20 patients, 35.1%). The 48 patients (82.8%) had significant oral habits. Unilateral chewing was seen in 35 patients (72.9%), bruxism in 27 (56.3%), abnormality of posture in 14 (29.2%), habitual crunching in 10 (20.8%) and resting the check on the hand in 4 (8.3%), respectively. When comparing the primary symptoms to those at the time of examination, the patients with unilateral chewing and bruxism tended to have more complicated symptoms. In conclusion, the TMD symptoms of the patients with notable oral habits did not change or become worse during a period of about 5 years.

Adolescent↗

Appraisal of bone maturity age derived from broadband ultrasonic attenuation in Japanese children and adolescents.

It is clinically important to evaluate the level of skeletal maturation in juveniles to determine the appropriate timing for orthodontic treatment. The purpose of this study was to assess the age of bone maturity by using an ultrasonic bone analyzer (Cuba Clinical, McCue Ultrasonics Ltd., Winchester, U.K.), Broadband ultrasonic attenuation (BUA:dB/MHz) was measured at the left calcaneus as an effective indicator of the age of bone maturity. The subjects consisted of 249 males and 304 females aged 12 to 29 years who had not suffered constitutional bone disease or a disease of the endocrine system. The peak value of BUA considered as bone maturity was 104.44 at the age of 19 years in males and 77.80 at the age of 16 years in females, and the peak age range was indicated as 18-19 years in males and 13-16 years in females by statistical evaluation. The peak age range indicated by BUA was wider in females than that in males. The present results can be used as reference ages for maturity in growth prediction for orthodontic treatment of Japanese children and adolescents. The heights and weights of the subjects were also collected as basic data. A significant positive correlation was observed between BUA values and weight (r = 0.34 p < 0.01 in females, r = 0.52 p < 0.01 in males). BUA is known to describe the quality of bone because the calcaneus is a loading bone. The relation between bone quality and growth has not been discussed. Further research is required to investigate this relationship.

Adolescent↗

Malocclusion associated with abnormal posture.

Growth and development of maxillofacial morphology and oral function are closely interrelated. Oral function is comprised of articulation, swallowing, and chewing. Malocclusion may be caused by abnormal functions such as mouth breathing, tongue thrust swallowing, and unilateral chewing and by abnormal postures of oral circumferential muscles such as forward tongue thrust, tongue biting, and low tongue at rest. Forces from unintentional and habitual behaviors constantly acting on the maxillofacial and alveolar regions can cause the bony structures to generally deform, resulting in jaw deformity and malocclusion. Oral function also plays a vital role in maintaining body posture. In this study, clinical observations of oral postures examined maxillary protrusion and open bite, anterior crossbite and facial asymmetry. The unstable forces induced by abnormal posture were correlated with the varieties of malocclusion. Morphology, function, and posture were shown to be closely interrelated and to influence each other.

Child↗

Broadband ultrasonic attenuation of children and young adults in Japan.

The purpose of this study was to establish broadband ultrasonic attenuation (BUA: dB/MHz) as bone mineral density (BMD) norms for healthy young Japanese and to evaluate the standard values for an ultrasonic bone analyzer (Cuba Clinical, McCue Ultrasonics Ltd., Winchester, England), which facilitates BMD measurement without exposure to radiation. The subjects were 472 healthy young individuals with no endocrine or skeletal disorders, 197 males (mean age 16 y 5 m) and 275 females (mean age 15 y 7 m) aged from 5 to 29 years. BUA was measured at the left calcaneus. The subjects were divided into five age-stratified different age groups of five years intervals. The mean BUA values (dB/MHz) obtained were 40.6, 60.9, 78.0, 90.4 and 86.0 for males, and 41.9, 61.0, 73.4, 68.4 and 70.8 for females in the 5-9, 10-14, 15-19, 20-24 and 25-29 age groups, respectively. A significant positive correlation was observed between BUA and age in both males and females except in the male 25-29 age group and the female 20-24 and 25-29 age groups. A significantly different BUA between males and females was found in the 20-24 and 25-29 age groups (p < 0.001). The BUA values obtained in this study may serve as BMD norms for children and young adults. It might be thought that measuring BUA from childhood through early adulthood made it possible to determine peak values and peak periods of BMD, providing useful information for assessment of growth and development.

Adolescent↗

Morphological evaluations in skeletal Class III malocclusion requiring maxillofacial surgery using orthognathic surgical analysis.

The purpose of this study was to establish a Japanese standard norm for orthognathic surgical analysis to be used in clinical applications and to clarify maxillofacial morphological characteristics in skeletal Class III malocclusions requiring orthognathic surgery. The materials were pretreatment lateral cephalometric radiographs in the relaxed lip posture from 50 subjects with skeletal Class III malocclusions diagnosed as requiring orthognathic surgery. The control group consisted of 50 subjects with normal occlusion and well-balanced faces. Detailed cephalometric measurements were recorded and analyzed statistically. The skeletal, dental, and soft tissue measurements from the normal group did not reveal any marked differences between the sexes. The Class III group exhibited a more retrognathic maxilla and prognathic mandible, a steeper mandibular plane, a more prominent chin, and a larger lower facial height in the skeletal measurements; a significant lingual inclination of the mandibular incisor in the dental measurement; and a more concave profile with prognathic mandible, a larger lower facial height, a more acute nasolabial angle and chin in the soft tissue measurements. We suggest that this analysis can be clinically useful in diagnosis, treatment planning, and posttreatment evaluation for orthognathic surgical cases who are Class III patients.

Case-Control Studies↗

Orthodontic treatment for jaw deformities in cleft lip and palate patients with the combined use of an external-expansion arch and a facial mask.

Patients with cleft lip and palate can suffer from contraction of the maxillary arch and anterior cross-bite accompanied by skeletal growth retardation. We use an appliance called an external-expansion arch and induce maxillary protraction using a facial mask in order to correct the anterior cross-bite and maxillary retrusion. In this paper, the method of application of these appliances and the effects of this therapy are reported here. The external-expansion arch consists of a labial wire, bands and a sectional arch. The 0.045-inch stainless steel wire extends along the maxillary dental arch. Hooks are soldered immediately distal to the lateral incisor and the distal leg of the vertical loop. The brackets are bonded to the maxillary anterior teeth, and a 0.016 x 0.016 inch sectional arch is set. The external-expansion arch is inserted into the headgear tube and ligated with the sectional arch using elastic thread. The maxillary bone is pulled by use of the facial mask and the elastic band. For traction, the force is about 300 g on each side, applied parallel to the occlusal plane or slightly downward. The duration of use is 8 to 12 hours per day. The external-expansion arch has several advantages: it can be applied from the early period of Hellman's dental age IIIA or IIC to improve anterior cross-bite. As it is easy to expand the anterior teeth and move individual teeth to the labial and buccal sides, establishment of a dental arch from severe collapse is not difficult. When an expanding device such as the Quad-helix is incorporated, lateral expansion becomes easier. Furthermore, it is easy to control the teeth vertically, and patient compliance is not necessary. Hence, this method is effective as a phase 1 treatment for orthodontic patients with cleft lip and palate characterized by maxillary retardation.

Adult↗

Measurement of lateral loads exerted on the maxillofacial region by habitual postures.

Lateral loads exerted on the maxillofacial region by habitual postures and habits may cause lateral shift or deformity of the mandible. These loads were measured with a desktop dynamic-strain gauge (DPM-600, Kyowa Co.) connected to a small, highly sensitive pressure sensor (PSL-A type, Kyowa Co.), and recorded with an oscillographic recorder (RDM-100A, Kyowa Co.). Measurements were taken with a pressure sensor embedded in silicone impression material placed in a vinyl chloride resin bag, on which pressures were applied. A preliminary study was conducted to obtain a proportional constant and a conversion formula for load calculation. The subsequent main study included 20 healthy male volunteers for load measurement in 12 positions. The mean load exerted on the mandible was 43.7 N when the subjects lay face down and approximately 20 N when they sat resting the lateral part of the chin on the hand, indicating that these loads are greater than regular orthodontic forces.

Adult↗

Evaluation of psychological factors in orthodontic patients with TMD as applied to the "TMJ Scale".

Physical and psychological evaluation have been required for TMD patients whose problems are multi dimensional. The questionnaire named the "TMJ Scale" was created to differentiate subjective TMD symptoms of patients. The purpose of this study was to clarify the reliability of the TMJ Scale for Japanese orthodontic patients with TMD and to differentiate the symptoms. Fifty orthodontic patients (average age 21y4m) with a chief complaint of TMD symptoms were compared with thirty patients (average age 21y1m) without TMD symptoms. The results were as follows: female patients in the symptom group in particular showed a higher degree of stress due to the chronic pain and abnormalities than those in the non-symptom group. Significant differences were observed in Pain Report, Joint Dysfunction and Global Scale at the 0.1% significant level, in Non-TM Disorder, Psychological Factor and Chronicity at the 1% level, and in Palpation Pain and Perceived Malocclusion at the 5% level in females. Few psychological problems were observed in male patients in the symptom group. Significant differences were observed in Range of Motion limitation at the 5% level in males. The differences in the psychological factors between male and female patients were clarified by using the TMJ Scale. These findings suggested that it was useful to differentiate the multiple symptoms, especially the psychological factors, by using the TMJ Scale for orthodontic patients with TMD.

Adolescent↗