Residual dentin thickness in upper anterior teeth after root canal preparation

Abstract

Objective To investigate the residual dentin thickness in upper anterior teeth at 4mm short of the apex and provide theoretical basis for the width of post space end preparation.Methods 60 upper anterior teeth with straight root canals were randomly assigned to 3 groups (n=20) and prepared,Group A:stainless steel file conventional root canal preparation technique; Group B:Gate-Glidden drill coronal preflaring + stainless steel file conventional root canal preparation technique; Group C:ProTaper for hand crown-down technique. The roots were cut horizontally at cement-enamel junction and 4mm short of the apex. The minimum width of residual root was measured on mesial and distal wall by a vernier caliper gauge.Results The minimum width means of residual root among 3 groups were larger than 1mm after root canal preparation. Linear correlation analysis showed that there were no correlation between the residual dentin thickness at cement-enamel junction and 4mm short of the apex besides B group distal wall.Conclusion 3# peeso reamer was recommended to prepare post space end in upper anterior teeth after root canal preparation in most cases.

目的探討上頜前牙根管預備后距根尖4mm處根管壁的最小厚度,為臨床預備樁腔末端的寬度提供理論依據。方法離體直單根管上前牙60個,隨機分為3組(n=20)進行根管預備,A組:不銹鋼根管銼常規法;B組:G型鉆根管冠部預處理+不銹鋼根管銼常規法;C組:手用ProTaper鎳鈦根管銼冠向下法。所有牙齒用金剛砂片分別在距根尖4mm處和釉牙骨質界處截斷牙根,截斷面垂直于根管。用游標卡尺測量斷面根管近中壁、遠中壁最薄處厚度。結果三種方法根管預備后距根尖4mm處和釉牙骨質界處剩余根管壁厚度均數都大于1mm。釉牙骨質界處與距根尖4mm處剩余根管壁厚度之間行直線相關分析,只有B組釉牙骨質界處與距根尖4mm處遠中壁剩余根管壁厚度之間存在線性相關,其它組之間均不存在線性相關。結論對于大多數病例,經三種方法根管預備后,推薦使用3#P型鉆預備上頜前牙樁腔末端。