Hansen E K, Asmussen E, Christiansen N C
Royal Dental College, Copenhagen.
Endod Dent Traumatol. 1990 Apr;6(2):49-55. doi: 10.1111/j.1600-9657.1990.tb00389.x.
The cumulative survival rate (retention of both cusps) and the fracture pattern of 1639 endodontically treated posterior teeth were assessed in a retrospective study. All teeth had an MO/DO or an MOD cavity restored with amalgam without cuspal overlays. The 20-year survival rate of teeth with an MO/DO cavity was markedly higher than that of teeth with an MOD cavity. The lowest survival rate was found for the upper premolars with an MOD cavity: 28% of these teeth fractured within 3 years after endodontic therapy, 57% were lost after 10 years, and 73% after 20 years. Generally, the cusp most prone to fracture was the lingual one, and lingual fractures caused significantly more damage to the periodontal tissues than did facial or total crown fractures. The severity of periodontal damage increased with posterior location of the tooth. By far the most serious failures, irrespective of the cavity type, were found for the upper second molar, as 10 of 29 fractures led to extraction. It is concluded that amalgam, especially in MOD cavities, is an unacceptable material for restoration of endodontically treated posterior teeth if used without cuspal overlays.
在一项回顾性研究中，对1639颗经牙髓治疗的后牙的累积生存率（两个牙尖保留情况）和骨折模式进行了评估。所有牙齿均有MO/DO或MOD洞型，用银汞合金修复且无牙尖覆盖。有MO/DO洞型牙齿的20年生存率明显高于有MOD洞型的牙齿。有MOD洞型的上颌前磨牙生存率最低：这些牙齿中有28%在牙髓治疗后3年内发生骨折，57%在10年后脱落，73%在20年后脱落。一般来说，最容易骨折的牙尖是舌侧牙尖，与颊侧或全冠骨折相比，舌侧骨折对牙周组织造成的损害明显更大。牙周损害的严重程度随着牙齿位于牙列后部而增加。到目前为止，无论洞型如何，最严重的失败情况发生在上颌第二磨牙，因为29例骨折中有10例导致拔牙。得出的结论是，如果不使用牙尖覆盖物，银汞合金，尤其是在MOD洞型中，是用于修复经牙髓治疗后牙的不可接受的材料。
