Evaluation of Chewing Movement in Skeletal Class III Patients with Orthognathic Treatment.

The objective of this study was to clarify the influence of improvement in morphology on chewing movement in patients with skeletal reversed occlusion following orthognathic treatment. A total of 10 patients with skeletal class III reversed occlusion undergoing orthognathic treatment were included in the study. A number of parameters, including chewing rhythm, maximum opening and closing velocities, and opening distance during chewing of gum, were measured in a pre- (Pre) and post-treatment (Post) group. The laterality and stability of the measured items were then compared between the two groups and with those in another group of subjects with normal occlusion (Control). Laterality of chewing movement was greater in the Pre group than in the Control group, and significant differences were noted in all parameters, apart from closing Vmax and opening distance. No significant difference was noted in any parameter between the Post and Control groups. The coefficient of variation was significantly higher in the Pre group than in the Control group, apart from for opening phase. All parameters showed a significant decrease in the Post group compared with in the Pre group, yielding a stable chewing movement. Comparison of the Post and Control groups revealed no significant difference in any of the parameters, apart from in the occluding phase. These findings suggest that orthognathic treatment of skeletal class III malocclusion improves chewing movement to levels close to those in subjects with normal occlusion.

Esthetic preferences of European American, Hispanic American, Japanese, and African judges for soft-tissue profiles.

INTRODUCTION: Our objectives were to determine whether observer and patient sex and race or ethnicity determine esthetic preferences for lip positions. METHODS: Four independent panels each consisting of 30 lay judges viewed pretreatment silhouette profiles of 10 European American, 10 Japanese, and 10 African American Angle Class I and Class II orthodontic patients. The panels included European Americans, Hispanic Americans, Japanese, and Africans. Profiles were traced from lateral cephalograms and manipulated so that the lip profile lay on the Ricketts' E-line or at various distances from the E-line from -8 to +4 mm in 2-mm increments. The judges selected the profile that they considered the most attractive and then classified the remaining 6 profiles as either acceptable or unacceptable. RESULTS: The mean preferred lip positions (mean +/- SD) were -2.58 +/- 1.92 mm for European American, -3.28 +/- 2.26 mm for Hispanic American, -3.45 +/- 1.92 mm for Japanese, and -2.13 +/- 1.95 mm for African judges. The African judges preferred more protrusive profiles compared with the Hispanic American (P <0.01) and Japanese (P <0.001) judges. Patient race or ethnicity and sex also contributed significantly to the judgments of profile esthetics (P <0.001). CONCLUSIONS: Judge race or ethnicity and patient race or ethnicity and sex significantly influence laypersons' standards for lip profile esthetics.

Expression of BMP7 is associated with resistance to diabetic stress: comparison among mouse salivary glands.

We determined mRNA levels of bone morphogenetic protein 7 (BMP7), a growth and differentiation factor belonging to the transforming growth factor-beta superfamily, in the salivary glands of mice with streptozotocin (200 mg/kg, i.p.)-induced diabetes. We also examined the effects of BMP7 on secretion of saliva and degenerative change in salivary glands in diabetic mice. In normal mice, BMP7 mRNA levels were high in the submandibular gland and low in the parotid gland, while in diabetic mice, levels were significantly decreased in the parotid gland, but not in the submandibular gland. No significant difference was observed in mRNA levels of BMP receptors between normal and diabetic mice. In diabetic mice, pilocarpine (4 mg/kg, i.p.)-stimulated salivary secretion showed a remarkable decrease in both parotid and submandibular gland, although degree of reduction was smaller in the latter. Notable degeneration with vacuolation and atrophy was also found in parotid gland, whereas degeneration of submandibular gland was slight. Administration of BMP7 (50 and 100 microg/kg, i.v.) in diabetic mice induced a significant increase in salivary secretion, with rate of recovery higher in parotid gland than in submandibular gland. In diabetic mice, BMP7 also exhibited a powerful protective effect in degenerated salivary gland, especially in parotid gland. These results suggest that BMP7 acts to prevent diabetic damage in salivary gland, and that its cytoprotective effect is closely correlated with mRNA levels in tissue.

Influence of extraoral lateral force loading on the mandible in the mandibular development of growing rats.

INTRODUCTION: The objective of this study was to elucidate the influence of extraoral lateral force loading of the mandible on mandibular development. METHODS: Thirty growing Wistar rats were divided into 3 groups: control, sham, and experimental. To determine longitudinal developmental changes, each animal was placed under anesthesia and immobilized in a custom-built body retainer to allow microcomputed tomography to be performed before and after the experiment. In the experimental group, a fixing device of aluminum was fitted to the zygomatic arch. Lateral force was then applied to the mandible with an open coil for 2 weeks. Stereoscopic images were constructed from 3-dimensional microcomputed tomography images. Absolute lengths and perpendicular heights from the baseline of the lower border of the mandible were measured. The images were superimposed at the baseline planes in each animal. After the final observation, the rats were killed, and the bilateral condyles excised. The condyles were decalcified by the standard method, stained with hematoxylin and eosin and toluidine blue, and observed under a microscope. RESULTS: Lateral force induced the mandible to shift toward the nonloaded side; absolute mandibular length at menton-condylion on the side where the load was applied was greater than that in the control group. No difference from the control group was noted on the nonloaded side, and there were no significant differences in perpendicular heights. Lateral loading on the mandible resulted in histopathologic changes: (1) on the side where the load was applied, the cartilaginous zone hypertrophied in the highest margin of the condylar head, the erosive zone expanded, and the width of the mandibular neck decreased; (2) the chondrocyte layer shifted to the medial side on the nonloaded side, and cartilaginous ossification occurred in the lateral direction immediately below the chondrocyte layer, which deformed the mandibular neck toward the medial side and caused asymmetric development of the mandible. CONCLUSIONS: These results demonstrate that extraoral lateral force loading during the growth stage causes asymmetrical mandibular development.

Dentofacial growth in patients with Sotos syndrome.

Sotos syndrome is an overgrowth syndrome leading to peculiar facial characteristics, large hands and feet, and mental retardation. The maxillofacial characteristics are metopic protrusion, a high and narrow palate and a tapered mandible. In this study, we evaluated changes in maxillofacial growth in 2 patients with cerebral gigantism during the peripubertal period. Patient 1 was a boy aged 8 years at the first examination. The face showed midface retraction and a tapered mandible. Maxillary median diastema with an OJ of 2.5 mm and OB of 1.0 mm was observed, and the molar region showed mandibular mesial occlusion. Radiography revealed a lack of 15, 25, 37, 47, 14, 24, 34 and 44. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 68 degrees and an SNB of 70 degrees , and the patient had leptoprosopia with a mandibular plane of 38.0 degrees . This plane was 45 degrees at the time of re-examination when the patient was 14 years old, showing an increase in the lower facial height and decreases in facial axis and depth. Patient 2 was a boy aged 14 years at the first examination. The face showed mandibular retrusion and tapering. The occlusion was angle class II div. 1, OJ 14 mm, and OB -1 mm. Cephalometrics demonstrated maxillary and mandibular retrusion with an SNA of 74.5 degrees and an SNB of 69.5 degrees , and the patient had leptoprosopia with a mandibular plane of 37.0 degrees . At the time of re-examination, when the patient was 16 years old, the mandibular plane was 42.5 degrees , showing an increase in lower facial height and decreases in facial axis and depth. In this syndrome, excessive facial height without mandibular forward overgrowth is observed. Since the facial height tended to increase by growth during the peripubertal period, maxillofacial vertical growth is considered important in the treatment of this syndrome.

Morphological study on quadruplets by cephalometric and model analyses.

Clarifying the genetic factors involved in maxillofacial growth and development is very important in orthodontic treatment planning and prognosis. However, few dental studies have examined multiple births. The present orthodontic evaluation was conducted using orthodontic data from a set of quadruplets. Orthodontic evaluation was performed on a set of quadruplets (1 girl and 3 boys) aged 9 years and 7 months at the initial visit. Although all 4 children weighed only about 1,400 g each at birth, height and body weight subsequently normalized. Mean skeletal age of the quadruplets was 10 years and 2 months, about 6 months ahead of their calendar age. In all 4 children, facial profile was mostly symmetrical and convex. Intraoral findings showed a Hellman's dental age of IIIA, together with spacing of the upper anterior teeth. Both overbite and overjet were 5-7 mm, and mesial step of the terminal plane was noted. Model analysis showed that tooth materials were on the large side, while arch width was narrow. Cephalometric analysis revealed that the ANB of the first- and fourth-born children was 6 degrees , and skeletal maxillary protrusion due to mandibular retrusion was diagnosed. The second- and thirdborn children exhibited no marked skeletal abnormalities.

Pressure on anterior region of palate during thumb-sucking.

Measurement of the pressure applied to the anterior region of the palate and incisor region of the mandible during thumb-sucking was carried out 3 female children. A polyethylene bag embedded with a high-sensitivity small pressure sensor was fixed on the ventral side of the thumb so that the baroreceptor could be interposed between the thumb and palate during thumb-sucking. The children were allowed to perform habitual thumb-sucking, and the resulting pressure signals were detected with a high-response dynamic strainmeter and recorded. Measured peak pressures were about 2-4.5 kgw, with large individual variation, and waveform patterns also varied. Characteristics of thumb-sucking habits and thumb-sucking pressure were related to malocclusion. Measurement of thumb-sucking pressure is believed to be effective for assessment of the qualitative relationship between thumb-sucking and malocclusion.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Lip seal study of Japanese adults with malocclusion.

The purpose of this study to clarify the factors an effecting lip seal in Japanese adults with malocclusion. Sixty-three malocclusion patients aged 20 to 27 years were randomly selected and compared with fourteen normal occlusion controls aged 22 to 26 years old. The subjects were divided into a good seal group and a poor lip seal group by observing the distance between the upper and lower lip at rest. Results of this adult study were as follows; There were no poor lip seals in normal occlusion subjects. Significant differences were observed for tongue thrust (p < 0.05) and mouth breathing (p < 0.05) between the good lip seal group and poor lip seal group of malocclusion subjects. Adults with poor lip seal should be treated for their malocclusion prior to be other functional approaches to improving their lip seal.

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.

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.