Tadao Fukui

The relationship between retruded contact position and intercuspal position in patients with TMJ osteoarthritis.

ABSTRACT This study was conducted to investigate the relationship between posterior mandibular excursion movement and temporomandibular joint osteoarthritis (TMJ OA) in 25 orthodontic patients with Angle Class I and Class II, using a six degrees-of-freedom measuring device and helical computed tomography. There were significant differences found in three-dimensional length, antero-posterior, absolute latero-medial and supero-inferior incisal, and condylar intercuspal position (IP)-retruded contact position (RCP) slides between bilateral, unilateral, and no condylar bone change groups. With respect to the types of condylar bone change, there were significant differences found in three-dimensional length, antero-posterior, and absolute latero-medial condylar IP-RCP slides between flattening, erosion and osteophyte groups. These results suggest that large three-dimensional, not only incisal but also condylar, IP-RCP slides might be related to the uni-/bilaterality and kind of TMJ pathosis, which might make such slides useful as clinical indices of TMJ OA.

A cross-sectional study on the relationship between craniofacial morphology and the coronoid process

Although there have been some reports on the relationship between craniofacial morphology and the activity of the temporal muscle attached to the coronoid process, such relationship is still unclear. The aim of the present study was therefore to investigate the relationship between the coronoid process and overall craniofacial morphology using lateral cephalograms of 60 female subjects (mean age 9.6 years) without mandibular deviation. Statistical testing was undertaken using stepwise regression analysis. Anterior coronoid marginal depth correlated negatively (r = 0.71) with gonial angle, SNA, and overjet. The coronoid angle also correlated negatively (r = 0.86) with both the vertical and horizontal lengths from sella to the coronoid tip as well as with the horizontal length from sella to the posterior ramus margin. Furthermore, the coronoid length correlated positively (r = 0.61) with the coronoid angle and the anterior coronoid marginal depth. The coronoid width was also positively (r = 0.69) correlated with overbite. Coronoid process morphology is related not only to mandibular morphology and position but also to maxillary position and the dental relationship in the anterior region. It therefore seems clear that coronoid process morphology might be related to temporal muscle functioning and its associated craniofacial morphological measurements.

Orthodontic treatment combined with temporary anchorage device for a case of Class II with osteoarthrosis of the temporomandibular joint

Abstract An adult female patient presented with open bite at Orthodontic Clinic, Niigata University Medical and Dental Hospital. The patient was diagnosed as skeletal Class II open bite with Class III molar relationship, because of temporomandibular joint-osteoarthrosis (TMJ-OA) and the congenital absence of the mandibular lateral incisors. To correct anterior open bite, surgical orthodontic treatment was considered, but post treatment stability was unpredictable and doubtful due to condylar erosion on the CT. We therefore determined that nonsurgical treatment with maxillary first premolars extraction and plate type temporary anchorage device (TAD) placement bilaterally for intruding the maxillary molars would be indicated. At the completion of the active treatment, ideal occlusion was achieved without further resorption of the condyles. Even two years after the treatment, the stable occlusion has been maintained. In conclusion, the orthodontic treatment with TAD is one of the potent devices to provide the ideal occlusion for the patient with TMJ-OA.

Nonsurgical treatment of adult skeletal Class III malocclusion with crowding and missing four premolars corrected with extraction of mandibular first molars

Abstract An adult male patient was present with anterior cross bite. He was referred to Orthodontic Clinic of Niigata University Medical and Dental Hospital for recommendation of surgical orthodontic treatment by general practitioner. The patient was diagnosed as skeletal Class III with anterior crowding and missing four premolars. To correct anterior cross bite and crowding, surgical orthodontic treatment was considered, but the patient refused orthognathic surgery. We therefore determined that nonsurgical treatment with mandibular bilateral first molar extraction would be indicated. After treatment, suitable overjet, overbite and proper functional occlusion were attained with Class I molar relation. Active treatment was 34 months, and the treatment result remained stable 2 years and 4 months after debonding.

Analysis of head and mandibular tapping movements in patients with mandibular protrusion.

Abstract The present study was conducted to investigate whether there was a functional coupling between the head and mandibular movements in ten patients with mandibular protrusion (MP) and ten control subjects with normal occlusion (Normal), using a six degrees-of-freedom measuring device. Single-peak waveforms were predominantly seen in both MP (98.2%) and Normal (99.3%). However, vertical displacements of the upper and lower incisor points (VDUIP and VDLIP) were all significantly larger in MP than those in Normal. The ratio VDUIP/VDLIP also increased more sharply with an increase in VDLIP in MP, compared to that in Normal. Mandibular rotation in MP was also significantly larger than that in Normal. The results showed that, in MP, the head moves more vertically in rhythmical coordination with mandibular movement during tapping. Finally, it may be that this larger vertical head movement is related to the greater condylar rotation in MP subjects.

Clinical Statistical Study on Changes of TMJ Disorders in Patients with Surgical Orthodontic Treatment.

The symptoms of temporomandibular joint disorder (TMD) in 33 patients indicative for surgical orthodontic treatment (8 males and 25 females, mean age of 22.5 years) were evaluated before treatment, during presurgical orthodontic and after treatment respectively through the questionnaires and the study casts. The patients were divided into 18 mandibular prognathism, 4 mandibular retrusion, 15 asymmetry, and 4 open bite cases.1. There was a significant difference in incidence of TMD symptoms between before (81.8%) and after (48.5%) treatment in all the patients.2. Incidence of TMD disorders decreased from 86.7% to 60.0% in asymmetry, from 72.2% to 27.8%(p<0.05) in mandibular prognathism and from 50% to 25% in open bite from before to after treatment, while in mandibular retrusion it remained 75% before and after treatment.3. The incidence of joint noise was 100% in mandibular retrusion and 46.7% in asymmetry before and after treatment, while it decreased from 44.4% to 22.2%(p<0.05) in mandibular prognathism and from 25% to 0% in open bite. Joint noise showed various changes during presurgical orthodontics in each malocclusion.4. The incidence of difficulty in mouth opening remained 50% in mandibular retrusion before and after treatment, while it decreased from 26.7% to 6.7% in asymmetry and from 16.7% to 5.6% in mandibular prognathism from before to after treatment. The open bite patients did not show difficulty in mouth opening both before and after treatment. Incidence of difficulty of opening tended to decrease in asymmetry and mandibular prognathism during presurgical orthodontics, while it worsened in mandibular retrusion.5. Mean value of VAS (Visual analog scale) in mandibular retrusion, which was used as an indicator for pain of temporomandibular joint, decreased from 60.0±42.4 to 40.4±14.1 from before treatment to presurgical prthodontics, however, it increased and showed 65.0±21.2 after treatment. Although VAS in asymmetry and mandibular prognathism showed 27.5±23.3 and 30.0±22.9 before treatment, and 27.0±17.9 and 27.5±19.4 presurgical orthodontics respectively, it decreased to 6.7±2.9 and 5.0 after treatment respectively. Open bite did not show pain of TMJ before and after treatment.These results suggested that symptoms of TMD in asymmetry and mandibular prognathism tend to be improved by surgical orthodontic treatment, but there were some cases of mandibular retrusion that did not improve.