The purpose of the present study was to evaluate the shear bond strength of resin-modified glass ionomer cement (RMGIC) and various materials utilized for orthodontic brackets and crown restorations. A conventional resin bonding system (Orthomite Superbond : SB) was used as a positive control. Three types of materials, such as metals, ceramics, and plastics, and human enamel as a control were prepared for this study. In the RMGIC study, the effect of surface treatment, such as primer treatment by functional monomer for metal and silane coupling for inorganic materials, was also considered in regard to the shear bond strength. The following results were obtained.
1. The shear bond strengths of SB to the tested materials were in the range of 27.8-39.8 MPa, nearly equivalent to those of SB to human enamel (39.0 MPa).
2. The shear bond strengths of RMGIC to the tested materials were in the range of 0.1-13.9 MPa, lower than those of SB to the tested materials and those of RMGIC to human enamel (25.6 MPa).
3. The shear bond strengths of RMGIC and all tested materials increased when a proper surface treatment, such as alloy primer or silane coupling agent, was applied to the tested materials. However, the shear bond strength of RMGIC to the polycarbonate showed the lowest level even after several surface treatments.
These results suggest that surface treatment on metals, ceramics, and most plastics would be effective for the adhesion of RMGIC. However, further modification or another surface treatment would be required for the bonding characteristics between RMGIC and polycarbonate.

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In the clinic, a coloration and accumulation of plaque might appear after orthodontic bracket debonding with remaining adhesives and a rough enamel surface.
In this study, enamel surface roughness was investigated with a roughness meter and morphology with a scanning electron microscope (SEM) after bracket debonding and polishing by various methods.
A total of 32 extracted human premolar teeth were cleaned and conditioned without pumice, and enamel surface roughness was then measured.
Orthodontic brackets were bonded with 4-META/MMA-TBB resin to 32 premolar teeth. After 48 hours, the brackets were debonded and polished in 16 methods, and surface roughness was measured again.
After the measurement, the enamel surface was platinum coated and examined with the SEM. We then took 50×, 500×, 1,000×and 5,000×photomicrographs of the enamel surface.
There were significant differences of enamel surface roughness in debonding in 12 of the 16 methods (p<<0.05).
And with the SEM observation, the following was cleared.
1. Excess resin remained on the enamel surface after debonding and polishing (Round bur, Pro-Care & Rubber cup, Pro-Care & Brush cone).
2. Excess resin was removed and polished to the level of resin tag (Composites Polishing System [40g]).
3. Excess resin was removed and polished to below the Acid & acetone resistant layer (Super fine, Diamond Polishing System, Aurora Poly Dia, Sof-lex, Composites Polishing System [80g], Silicon cup point).
The method that uses the Composites Polishing System (40g) is nearly an ideal debonding method because the enamel surface was smooth. No excess resin remained and too much enamel was not removed.

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This study was conducted to clarify the influence of palatoplasty on maxillary growth.
Noncleft children (NC group) and patients treated with the push-back (PB group) method, the buccal musculomucosal flap (BF group) method, and two-stage palatoplasty combined with a Hötz plate (TS group) were compared in regard to maxillofacial growth by the use of a lateral cephalogram obtained before orthodontic treatment.
The results were as follows :
In comparison with the NC group, the PB group is short in height and depth of maxilla, and the points of the mandible are back and upward corresponding to the change of the maxilla.
In comparison with the NC group, the TS group at point U1 and the point of mandible is downward at every point except L1.
In comparison with the NC group, the BF group position of U1 and Mo is backward.
In comparison with the BF group, the PB group's significant difference is in the anteroposterior direction on the maxilla.
In comparison with the TS group, the BF group showed no significant difference. The entire balance on the maxillofacial shape of both the BF group and the TS group was similar.
From these results, the different palatoplasty brought on the different results in maxillofacial growth, and palatoplasty is considered a possible way to improve surgical methods.

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Purpose
The purpose of this study was to compare the contact patterns of tongue-to-palate and alveolar or maxillary dentures in edentulous patients with and without their dentures during the production of the [ta], [ki] and [ra] sounds. Methods
The subjects consisted of 10 edentulous adults (3 men and 7 women) for the [ta] and [ki] pronunciation trials and 6 edentulous adults (2 men and 4 women) for the [ra] pronunciation trials. Artificial palates made of black vinyl covering the palate and the alveolar ridge of the maxilla were coated with white alginate powder and were then inserted into the mouths of the subjects. After a pronunciation of the test sounds, the tongue contact areas on the artificial palates were demonstrated by a change in color from white to black wherever the powder had been moistened.
An image processor system was employed for averaging five samples of the same sound for each subject. The averaged pattern of each subject's palatograms was then converted to the standardized dental arch form, added, and stored. Seventy percent of each subject's common parts were extracted from the combined palatograms of the same sound. Results and Conclusion
On comparing the contact patterns of the edentulous stage (E) with the contact patterns of the denture-wearing stage (D) in both [ta] and [ki] sounds, the entire contact area of the E was found to be wider than that of the D (significant difference p<0.05 for [ki]), However, for the [ra] sound, the entire contact area of the E was found to be narrower than that of the D.
In the [ta] and [ki] sounds, the contact area anterior to the first premolar of the E was narrower than that of D; however, the contact area posterior to the first premolar of the E was wider than that of D.

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This study was carried out to determine statistical information concerning the crowns and the fixed partial dentures (total number, type and rate of crowns, number of vital or non-vital abutment teeth, etc.) which were placed in the outpatients in the Department of Fixed Prosthodontics at Showa University Dental Hospital from April 1998 to March 1999.
The following results were obtained;
(1) The total number of crowns and fixed partial dentures produced were 988; among them, crowns totaled 781 (79.0%) and fixed partial dentures, 207 (21.0%).
(2) Most of the crowns were full cast crowns (417, 53.4%); the second most commonly produced was porcelain-fused-to-metal crowns (153, 19.6%); the third was resin-faced cast crowns (152, 19.5%).
(3) Resin-faced cast crowns and porcelain-fused-to-metal crowns were most commonly used for the anterior teeth; full cast crowns and porcelain-fused-to-metal crowns, for the premolar teeth; full cast crowns, for the molar teeth.
(4) Fixed partial dentures located in the posterior region were 52.2%; the antero-posterior region were 25.1%; the anterior region were 22.7%.
(5) With regard to the relationship between the missing teeth and the abutment teeth of the fixed partial denture, three-unit fixed partial dentures (one missing tooth with two abutment teeth) were most frequently treated in all regions.
(6) The crowns covered by the insurance dental service were 74.6%; the fixed partial dentures were 67.1%.
(7) Concerning the abutment teeth of the crowns, non-vital teeth were 87.1% implant abutments were 2.4%; non-vital teeth of the fixed partial dentures were 67.8%; implant abutments were 2.3%.

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