インプラント支持の補綴物が短縮歯列弓の被験者の咬合力と咀嚼効率に及ぼす影響

Effect of implant-supported prosthesis on the bite force and masticatory efficiency in subjects with shortened dental arches.

抄録

本研究の目的は、第1大臼歯にインプラント支持型補綴物を装着した歯列弓短縮型（SDA）被験者の咬合力と咀嚼効率の変化を評価することであった。下顎大臼歯が両側欠損しているSDA被験者（実験群）10名を募集した．各被験者に下顎第1大臼歯部にテーパースレッドインプラントを1本ずつ埋入し，修復を行った．咀嚼効率は，術前と修復後3ヶ月に，生のニンジンを噛んで放出される色素を「分光光度計」で530nmで測定することにより，客観的に評価した．咬合力は，術前，6週間後，修復後3ヶ月後に「咬合力測定器」を用いて評価した．対照として，年齢，性別，身長，体重が完全に歯牙適合している10名の被験者を用意した．その結果，実験群は対照群に比べ，修復前と修復後6週間の平均最大咬合力が有意に減少した（P < 0.05）．3ヶ月後の平均最大咬合力はコントロール群より小さいが，その平均差は統計的に有意ではなかった．対照群と実験群の咀嚼効率の平均値は、修復前は統計的に有意（P < 0.05）でしたが、修復後3ヶ月では統計的に有意ではありませんでした。したがって，インプラント支持下顎骨修復後，SDAの被験者全員において，咬合力と咀嚼効率が増加し，3ヵ月後には完全歯列の被験者と同等になったと結論づけられる．

The aim of the study was to assess changes in bite force and masticatory efficiency in shortened dental arch (SDA) subjects rehabilitated with implant-supported restoration for 1st molar. Ten SDA subjects with bilaterally missing mandibular molars (experimental group) were recruited. In each subject, one tapered threaded implant was placed bilaterally in 1st mandibular molar region and restored. Masticatory efficiency was evaluated objectively by measuring the released dye from chewed raw carrots, with a 'spectrophotometer' at 530 nm preoperatively and at 3 months after restoration. Bite force was evaluated using 'bite force measuring appliance' preoperatively, at 6 weeks and at 3 months after restoration. Ten completely dentate-matched subjects (in terms of age, sex, height and weight) acted as control. The results revealed that as compared with the control group, the experimental group showed significantly less (P < 0.05) mean maximum bite force at pre-restoration and at 6 weeks after restoration. Although at 3 months the mean maximum bite force value was less than the control group but the mean difference was statistically insignificant. The mean difference of masticatory efficiency between control and experimental group was statistically significant (P < 0.05) before restoration, but was statistically insignificant at 3 months after restoration. Thus it was concluded that after the restoration of mandibular arch with implant-supported prosthesis, both bite force and masticatory efficiency of all SDA subjects increased and were comparable to that of matched completely dentate subjects after 3 months.