The failure rate of NHS funded molar endodontic treatment delivered in general dental practice

Abstract

VERIFIABLE CPD PAPER• Mandibular first molar root fi llings have low failure rates over a fi ve-year period.• Failure is most likely to occur in the first year following placement of the root fi lling.• Failure rates are similar for optimal versus sub-optimal appearance of root-fi llings on radiographs.• Coronal restoration is an important predictor of survival with crowns performing better than plastic restorations. I N B R I E F RESEARCHObjective To describe the quality and record the outcomes of root canal therapy on mandibular, first permanent molar teeth provided by GDPs working according to NHS contracts. Design Descriptive, retrospective cohort study. Setting Twelve general dental practices in Salford, North West England. Subjects and method All patients aged 20-60 years at tending the practices who had received a NHS-funded root filling in a mandibular first permanent molar between January 1998 and December 2003. The radiographic quality of root fillings in the teeth was assessed by an endodontic specialist and categorised into optimal, suboptimal and teeth which had no radiograph, or an unreadable radiograph. Teeth were also dichotomised into those restored with a crown and those restored with an intracoronal restoration. Failure as an outcome was defined as if a tooth was extracted, the root filling was replaced or periradicular surgery was performed on the tooth. Crude failure rates per 100 years were calculated for optimally, sub-optimally root filled teeth and for those with no or an unreadable radiograph, and according to how the tooth was coronally restored. Survival was assessed using Kaplan-Meier curves and Cox proportional hazards were used to determine factors linked with increased failures. Results One hundred and seventy-four teeth were included in the study, of which 16 failed. The crude failure rates per 100 years with a root filled tooth were very low and differed little (p = 0.9699) for optimally (2.6), sub-optimally (2.5) root filled teeth and for those with no or an unreadable radiograph (2.9), with approximately one in 37 root filled mandibular first molar teeth failing each year. The majority of root fillings fail within the first two years (N = 10, 62.5%). Some 67 teeth (38.5%) were restored with a crown, none of which failed during the follow up period compared to those with a plastic restoration (p = 0.0004). Conclusions The very low failure rates have significant implications for the design of research studies inves tigating outcomes of endodontic therapy. The similar failure rates for teeth that had optimal and suboptimal root fi llings suggest that endodontic treatment is not as technique sensitive as previously thought. The results also support the notion that the coronal restoration is more important than radiographic appearance of the root fi lling.

A 20‐year historical prospective cohort study of root canal treatments. A Multilevel analysis

“…The need for long‐term clinical studies on teeth following root canal treatment is essential (Tickle et al . , Fonzar et al . , Ng et al .…”

“…The vast majority of clinical studies on root filled teeth are based on 5–10 follow‐up periods (Tickle et al . , Fonzar et al . , Ng et al .…”

Ten‐year follow‐up of root filled teeth: a radiographic study of a Danish population

“…, Salehrabi & Rotstein ) and after endodontic treatment performed by general dental practitioners (GDPs) in the UK (Tickle et al . ) and Taiwan (Chen et al . ).…”

Outcome of non‐surgical re‐treatment

“…Academic clinicians interested in identifying prognostic factors have tended to opt for a combination of radiographic and clinical signs of resolution of periapical disease (38). The health planning professional or dental insurance company may be more interested in the survival of the root canal fillings or treatment (43)(44)(45)(46)(47) and tooth retention or survival (22,48,49). The health planning professional or dental insurance company may be more interested in the survival of the root canal fillings or treatment (43)(44)(45)(46)(47) and tooth retention or survival (22,48,49).…”

“…The perceived ''threat'' to root canal treatment from the competing treatment option (extraction and implant-supported prosthesis) has popularized the study of ''tooth survival'' (21,45,48,49,(83)(84)(85)(86)(87)(88)(89)(90)(91)(92)(93). Apart from tooth extraction, other competing outcomes such as the tooth undergoing further non-surgical or surgical treatment may also be considered failure events (45)(46)(47). Apart from tooth extraction, other competing outcomes such as the tooth undergoing further non-surgical or surgical treatment may also be considered failure events (45)(46)(47).…”