Yukio Seino

Influence of tooth-to-denture-base discrepancy on space closure following premature loss of deciduous teeth

Influence of tooth-to-denture-base discrepancy on so-called physiologic migration of the first molar was studied on serial dental casts of 116 boys and girls, obtained through a dental health program for school children in an area in which there was no dentist. The alteration of spaces following premature loss of deciduous molars was examined comparing the anterior to posterior discrepancies between tooth and denture base. Modes of space alteration showed positive correlation with the size of the discrepancy, especially in the mandibular dental arches. The space deficiency in the posterior region seemed to have a positive effect on the mesial migration of the first molar. Mesial migration of the first molar seems to be pathologic rather than physiologic and is strongly affected by tooth-to-denture-base discrepancies. Space maintenance does not seem to be useful, because it is not necessary in minimum discrepancy cases and is not effective in severe discrepancy cases.

Clinical application of dental implant with root of coated bioglass: Short-term results

During the last 4 years 73 dental implants with root-coated bioglass to replace one to three teeth in the premolar and molar sites of the mandible were inserted. The bonding ratio between implant and bone was observed clinically 1 year after implantation and installation of the superior structure. This ratio measured 52.4% to 63.3%. An acoustoelectric tester was developed that advanced our skills. The emphasis was placed on a tight fit between implant and surrounding bone.

A study of oligodontia in orthodontic patients

In the present study, we reviewed the patients who were diagnosed as skeletal mandibular prognathism who underwent a sagittal split ramus osteotomy (SSRO) comparing the perioperative change of the tongue posture and the pharyngeal airway. Also, we considered it versus a postoperative change by SSRO about maxillofacial morphology of obstructive sleep apnea hypopnea syndrome (OSAS) and the pharyngeal airway. We reviewed 20 patients diagnosed as skeletal mandibular prognathism in our hospital. We compared the lateral cephalogram data of the patients one month before the operation (T1), one month after (T2), and one year after (T3), with 53 students belonging to our university setting as the normal group who displayed nothing abnormal with the maxillofacial, and 21 patients diagnosed as OSAS at the Tsukuba University Hospital.