However , variability was substantial .
Restoration type , material s , the patient , the operator , the practice environment and type of care system appeared to influence longevity .
Objective To conduct a systematic review of the literature on the longevity of routine dental restorations in permanent posterior teeth , and to identify and examine factors influencing its variability .
The effect of setting time on the clinical performance of a high-copper amalgam alloy.
The purpose of this clinical study was to evaluate the factor of the setting rate/Eames working time on fracture at the margins of amalgams . One batch of a high-copper amalgam was modified to obtain two setting rates , one fast and one slow setting .  Two dentists originally placed 134 amalgam restorations in 23 patients . Both dentists used a rubber dam throughout the restorative procedure and prepared cavities as conservatively as possible . The amalgams were condensed by h and and carved with sharp instruments . At 1 year 124 restorations and at 2 years 115 restorations were evaluated for fracture at the margins . Results indicated that there was no significant clinical difference between a slow- and fast- setting alloy , nor was there a difference between the operators
However , variability was substantial .
Restoration type , material s , the patient , the operator , the practice environment and type of care system appeared to influence longevity .
Objective To conduct a systematic review of the literature on the longevity of routine dental restorations in permanent posterior teeth , and to identify and examine factors influencing its variability .