Periapical Status of Non–root-filled Teeth with Resin Composite, Amalgam, or Full Crown Restorations: A Cross-sectional Study of a Swedish Adult Population Victoria Dawson, DDS,* Kerstin Petersson, DDS, PhD,* Eva Wolf, DDS, PhD,* and Sigvard A ˚ kerman, DDS, PhD † Abstract Introduction: Experimental studies show that dental pulp cells respond unfavorably to contact with resin com- posite restorative material. Hypothetically, in a random population, the frequency of apical periodontitis should be higher for teeth restored with resin composite than with amalgam. Therefore, the aim was to compare the periapical status of non–root-filled teeth restored with resin composite, amalgam, or laboratory-fabricated crowns in an adult Swedish population. Methods: The subjects comprised 440 individuals from a randomly selected sample of 1,000 adult residents of a Swedish county. The type, material, and quality of the restorations were recorded for all non–root-filled teeth by clinical ex- amination and intraoral clinical photographs. Periapical status was evaluated on panoramic radiographs. The as- sociation between periapical status and type, material, and quality of the restorations was analyzed using the chi-square test and logistic regression analysis. Results: There was no significant difference in the frequency of api- cal periodontitis (AP) between teeth restored with resin composite or amalgam (1.3% and 1.1%, respectively). The frequency of AP for teeth restored with laboratory- fabricated crowns was significantly higher (6.3%). Regres- sion analysis showed no association between AP and resin composite restorations but a significant association with laboratory-fabricated crowns. Conclusions: The results indicate that the risk of damage to the pulp-dentin com- plex from exposure to resin composite material and dentin bonding agents shown in experimental studies is not re- flected in the clinical setting. However, in the study sam- ple, AP was diagnosed in a significantly higher proportion of teeth restored with laboratory-fabricated crowns. (J En- dod 2014;40:1303–1308) Key Words Apical periodontitis, cross-sectional study, crowns, dental amalgam, dental pulp, epidemiology, periapical status, resin composite I n June 2009, further use of amalgam was prohibited in Sweden on environmental grounds. However, resin composite has been the predominant restorative material since the 1990s; the major advantages over amalgam are superior aesthetics and less invasive cavity preparation. Experimental research has shown shrinkage of resin composite during the polymerization process, implying a risk of microbial leakage, leading to pulpal inflammation, with subsequent pulp necrosis and the development of apical periodontitis (AP) (1–3). Other complications frequently associated with polymerization shrinkage stress are secondary caries and postoperative sensitivity and pain although there is limited clinical supportive evidence (4). In experimental studies, adverse cellular responses to resin composite material and dentin bonding agents have been observed in dental pulp cells (5, 6). There are few clinical studies of the association between endodontic complica- tions and resin composite restorations. In 1 such study, vital teeth were restored with amalgam (n = 377) or resin composite (n = 225); after a follow-up period of 36 months, pulpal breakdown was more frequently associated with the resin composite than the amalgam restorations (7). In contrast, 2 other studies reported no significant difference in pulpal complications in teeth restored with resin composite or amalgam in terms of subsequent endodontic treatment over follow-up periods of 5–12 years (8, 9). In 2 further studies, all teeth restored with a class I or II resin composite restoration remained vital as tested by electrical and/or cold stimuli after 4–11 years (10, 11). Although there does not seem to be any obvious difference in pulpal status or pulpal complications between teeth restored with resin composite and amalgam, periapical status was not evaluated in the previously mentioned studies. Thus, no conclusions can be drawn from the literature with respect to changes in periapical status after restoration with resin composite or amalgam. There are several follow-up studies of the periapical status of non–root-filled teeth with full crown restorations, primarily as abutments for fixed partial dentures. The re- ported frequencies of AP vary, from 3%–15% for observation times from 2–25 years (12–15). In a cross-sectional study, Saunders and Saunders (16) reported AP on 19% of non–root-filled teeth restored with crowns. Although some variations in results may be attributable to differences in study design, observation time, criteria, and methods of assessing periapical status, all studies indicated an increased frequency of AP on teeth with full crown restorations. In longitudinal epidemiologic studies, non–root-filled teeth with periapical pathol- ogy have been associated with carious lesions or the presence of a coronal restoration of poor quality (17). Experimental studies indicate adverse effects of resin composite materials on the dental pulp as well as a risk of shrinkage of the filling material, with microbial leakage as a consequence. Extrapolating these findings to the current clinical From the Departments of *Endodontics and † Oral Diagnostics, Faculty of Odontology, Malm€ o University, Malm€ o, Sweden. Address requests for reprints to Dr Kerstin Petersson, Department of Endodontics, Malm€ o University, Faculty of Odontology, SE 205 06 Malm€ o, Sweden. E-mail address: kerstin.petersson@mah.se 0099-2399/$ - see front matter Copyright ª 2014 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.05.002 Clinical Research JOE — Volume 40, Number 9, September 2014 Coronal Restorations and Periapical Status 1303