Study proves effectiveness of stainless-steel crowns in restoring permanent teeth
MILTON, Ontario, Canada: Dental crowns are available in a variety of materials, making it difficult for dentists to decide which material will best restore a tooth that has been broken or worn down. While it has been proved that stainless-steel crowns (SSCs) are highly effective in restoring posterior primary teeth, their efficacy in restoring posterior permanent teeth has not yet been scientifically proved. Now, a recent study has examined the long-term clinical outcomes of using SSCs in a special needs population and confirmed that SSCs are a viable and durable option for the treatment of both types of dentition.
In the retrospective cohort study, the researchers performed a clinical and radiographic analysis of 271 patients who showed a poor level of oral hygiene, were at high risk of dental caries and had at least one SSC restoration. A total of 2,621 posterior permanent tooth restorations were documented: 766 SSCs, 1,651 amalgam restorations and 204 composite resin restorations.
“I noticed that many adults with and without special needs who had their dental care provided by dentists in the community were presenting to our hospital emergency department with posterior permanent teeth restored with very large multisurface amalgam or resin restorations that had failed. The persons were usually in pain and the teeth were, in many cases, unrestorable or required endodontic therapy,” Dr. Alison Sigal, a pediatric dentist and founder of the Little Bird Pediatric Dentistry in Milton, told Dental Tribune International. “I knew from my training in pediatric dentistry that SSCs were very successful in primary posterior teeth and wondered whether they could be equally successful in the permanent posterior dentition,” she added.
The findings showed that new SSC and amalgam restorations had a ten-year survival rate of 79.2% and 63.5%, respectively. Although the researchers recorded 91 SSC failures, Sigal gave the assurance that the majority of the crowns that were lost were due to generalized periodontal disease and not due to the failure or loss of the restoration.
Of the 528 failed conventional restorations that were replaced by the dentists, 60% were replaced with SSCs. After the defective restorations had been replaced, the patients had a mean alveolar bone loss at mesial and distal sites of 1.36 mm and 1.40 mm, respectively, which was deemed healthy.
“SSCs are full-coverage restorations and as such will add strength to the remaining tooth and are generally not at risk for dental caries, whereas amalgam and composite resin restorations both weaken the remaining tooth structure and are susceptible to recurrent caries and fracture or margin failure. Further, as found in our study, teeth that had failed amalgam and/or composite resin restorations that would otherwise be deemed nonrestorable with a larger surface restoration and to be extracted were able to be preserved with the placement of the SSC restoration,” she noted.
Since the study was conducted on persons with special needs, Sigal cautions that the findings cannot be generalized. However, she believes that SSCs would be similarly successful in restoring permanent posterior teeth in the general population.
“SSCs are durable long-term restorations that are less expensive than other full-coverage restorations and should be considered as a potential restoration for both primary and permanent posterior teeth, especially in persons with special needs and those with limited finances or failing oral hygiene,” Sigal concluded.
According to the American College of Prosthodontists, an estimated 2.3 million implant-supported crowns are produced annually in the U.S.
The study, titled “Stainless steel crowns as a restoration for permanent posterior teeth in people with special needs: A retrospective study,” was published online on Dec. 27, 2019, in the Journal of the American Dental Association, ahead of inclusion in an issue.