James C. Kessler - Fundamentals of Fixed Prosthodontics

A survey of 571 fixed prosthodontists, nonspecialist restorative dentists, and dental school faculty projected an average life span of 11.2 years for simple amalgams and 6.1 years for complex amalgams. 21One group of 125 complex amalgams was reported to have a 76% survival rate at 15 years,20 whereas another group of 171 complex amalgam restorations exhibited a 50% survival rate at 11.5 years. 22

Composite resin restorations have not been included in many longevity studies. A study of dental school patients that did incorporate them reported a 10-year survival rate of 55.9%. 14Another report, based on a general patient population, described a shorter life span for composite resin restorations, with 50% of them having failed in 6.1 years. 23

Mount 24disclosed an overall success rate of 93% for 1,283 glass-ionomer restorations for up to 7 years, with the rate varying from 2% to 36% depending on the class of cavity and the brand of cement. In that study, the patients evaluated had been treated by only two dentists, and not all of the restorations had been in place for the full 7-year span of the study. While promising, these figures must be assessed cautiously until longer studies of a broader population have been completed.

Schwartz et al, 25after studying a group of 791 failed restorations, reported mean life spans, at failure, of 10.3 years for full crowns, 11.4 years for three-quarter crowns, and 8.5 years for porcelain jacket crowns (anterior all-ceramic crowns). The mean life span for all fixed prosthodontic restorations was 10.3 years. Walton and associates, 26evaluating a group of 424 restorations, found full crowns lasting 7.1 years, partial veneer crowns 14.3 years, metal-ceramic crowns 6.3 years, inlays and onlays 11.2 years, and porcelain jacket crowns 8.2 years.

The dentists responding to Christensen’s survey estimated the longevity of crowns to be from 21 to 22 years. 19The estimates supplied by the respondents to a survey by Maryniuk and Kaplan 21were 12.7 years for metal-ceramic crowns and 14.7 years for all-gold restorations. Kerschbaum, 27examining German insurance records, found 91.5% of gold crowns still in the mouth after 8 years. In a review of records in 40 Dutch dental offices, Leempoel et al 28told of 10-year survival rates of 98% and 95.3% for full crowns and metal-ceramic crowns, respectively.

A compilation of longevities from several studies is presented in Table 6-2.

The question of longevity is an important one to consider when choosing treatment for a patient. The more destructive the preparation required for the restoration, the greater the potential risk for the tooth and ultimately the greater expense. In 1989, it was estimated that if a crown were placed in a patient’s mouth at age 22, at a fee of $425, attendant services and replacements of that crown would cost the patient nearly $12,000 considering an average life expectancy of 75 years. 32Today, the original fee may be double, or $850, with a corresponding doubling of the subsequent effect, resulting in a cost to the patient of nearly $24,000.

Table 6-2 Longevity of single-tooth restorations

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19. Christensen GJ. The practicability of compacted golds in general practice—A survey. J Colo Dent Assoc 1971;49:18–22.

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21. Maryniuk GA, Kaplan SH. Longevity of restorations: Survey results of dentists’ estimates and attitudes. J Am Dent Assoc 1986;112:39–45.

22. Robbins JW, Summitt JB. Longevity of complex amalgam restorations. Oper Dent 1988;13:54–57.

23. Qvist V, Thylstrup A, Mjör IA. Restorative treatment pattern and longevity of resin restorations in Denmark. Acta Odontol Scand 1986;44:351–356.

24. Mount GJ. Longevity of glass ionomer cements. J Prosthet Dent 1986;55:682–685.

25. Schwartz NL, Whitsett LD, Berry TG, Stewart JL. Unserviceable crowns and fixed partial dentures: Life-span and causes for loss of serviceability. J Am Dent Assoc 1970;81:1395–1401.

26. Walton JN, Gardner FM, Agar JR. A survey of crown and fixed partial denture failures: Length of service and reasons for replacement. J Prosthet Dent 1986;56:416–421.

27. Kerschbaum T. Long-term prognosis of crowns and bridges today [in German]. Zahnarztl Mitt 1986;76:2315–2320.

28. Leempoel P, de Haan A, Reintjes A. The survival rate of crowns in 40 Dutch practices. J Dent Res 1986;65:565.

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30. Burke FJ, Lucarotti PS. Ten-year outcome of porcelain veneers placed within the general dental services in England and Wales. J Dent 2009;37:31–38.