Aim: To investigate the frequency of further interventions after root filling during a follow-up of 10 to 11 years, and to compare the outcomes with respect to type of coronal restoration and tooth group.Methods: Data from the Swedish Social Insurance Agency´s register of dental treatments were obtained to identify the teeth registered as root filled in Sweden 2009. Type of coronal restoration within 6 months after root filling, as well as the frequency of further interventions (nonsurgical retreatment, periradicular surgery, extraction, further direct and indirect restoration) were tracked in the data register until December 31, 2019. Descriptive statistics and Chi-square tests were used for statistical analysis.Results: Of the 215 611 teeth root filled in 2009, nonsurgical retreatment, periradicular surgery, and extraction were registered for 3.5%, 1.4% and 20%, respectively. The highest frequency of nonsurgical retreatment was registered for molars (4.2%), and periradicular surgery was most frequent in maxillary canines and incisors (2.3%). The highest frequency of extractions was registered for mandibular molars (25.1%). Directly restored teeth had higher frequency of nonsurgical retreatment (3.9%) and extraction (20.8%), compared to indirectly restored teeth (1.7% and 13.6%, respectively; P < 0.001). Of teeth restored with direct restoration within 6 months after root filling, 41.5% were registered with at least one further direct restoration and 14.7% with an indirect restoration. In the group of indirectly restored teeth, 9.3% and 7.1% underwent further restorative treatment with direct and indirect restoration, respectively. The differences registered between directly and indirectly restored root filled teeth were statistically significant (P < 0.001).Conclusions: The frequencies of nonsurgical retreatment and periradicular surgery were low 10 to 11 years after root filling, despite one in five root filled teeth being registered as extracted. Further interventions were significantly more common for directly restored teeth than for those indirectly restored.

Introduction: The aims were to investigate 1) the frequency of nonsurgical retreatment, root-end surgery, extraction, and further restorative treatment during a follow-up of 10 to 11 years after root filling and compare the frequencies according to tooth group and type of coronal restoration, and 2) the timing of nonsurgical retreatment, root-end surgery, and extraction.

Methods: Data were collected from the Swedish Social Insurance Agency's register. A search for treatment codes identified teeth root filled in 2009 and the type of coronal restoration (direct, indirect, unspecified) registered within 6 months of root filling. The root-filled teeth were followed 10-11 years, and further interventions were recorded. Descriptive statistics and Chi-square tests were used for statistical analysis.

Results: In 2009, root fillings were registered for 215,611 individuals/teeth. Nonsurgical retreatment, root-end surgery, and extraction were undertaken in 3.5%, 1.4%, and 20% teeth, respectively. The frequency of further interventions varied with respect to tooth group and type of coronal restoration, but only slightly for endodontic retreatments. Further interventions, except for root-end surgery, were registered more often for molars and directly restored teeth (P < 0.001). The majority of endodontic retreatments were undertaken within 4 years, while extractions were evenly distributed over 10-11 years.

Conclusions: The frequency numbers of nonsurgical retreatment and root-end surgery were low, despite one in five root-filled teeth registered as extracted. Further interventions were most common in molars and directly restored teeth. Endodontic retreatments were performed more often during the first 4 years.

Collaboration is essential to focus on the urgent research questions and to fill knowledge gaps in Odontology. Larger research consortiums have a better potential to utilize different competencies and other resources, and consequently increase research output. Bigger, more complex projects can be undertaken, which in turn improves the potential to attract external funding. Collaboration with other institutions also facilitates academic meriting, which is highly desirable from a Swedish perspective, especially since the number of senior researchers with formal competence to supervise doctoral research projects is lower than ever before. Here, we present EndoReCo, a Scandinavian research network in Endodontics initiated a decade ago with these very opportunities in mind. The article describes the results of this collaboration to date, highlights the success factors and difficulties, and aims to inspire others to similar collaborations in other disciplines.

Observational studies are non-interventional studies that establish the prevalence and incidence of conditions or diseases in populations or analyse the relationship between health status and other variables. They also facilitate the development of specific research questions for future randomized trials or to answer important scientific questions when trials are not possible to carry out. This article outlines the previously documented consensus-based approach by which the Preferred Reporting items for Observational studies in Endodontics (PROBE) 2023 guidelines were developed. A steering committee of nine members was formed, including the project leaders (PD, VN). The steering committee developed an initial checklist by combining and adapting items from the STrengthening the Reporting of Observational studies in Epidemiology (STROBE) checklist and the Clinical and Laboratory Images in Publications (CLIP) principles, as well as adding several new items specifically for the specialty of Endodontics. The steering committee then established a PROBE Delphi Group (PDG) and a PROBE Online Meeting Group (POMG) to obtain expert input and feedback on the preliminary draft checklist. The PDG members participated in an online Delphi process to reach consensus on the clarity and suitability of the items present in the PROBE checklist. The POMG then held detailed discussions on the PROBE checklist generated through the online Delphi process. This online meeting was held via the Zoom platform on 7th October 2022. Following this meeting, the steering committee revised the PROBE checklist, which was piloted by several authors when preparing a manuscript describing an observational study for publication. The PROBE 2023 checklist consists of 11 sections and 58 items. Authors are now encouraged to adopt the PROBE 2023 guidelines, which will improve the overall reporting quality of observational studies in Endodontics. The PROBE 2023 checklist is freely available and can be downloaded from the PRIDE website (https://pride-endodonticguidelines.org/probe/).

Objectives: To analyze the accumulated fees connected with root filling, permanent coronal restoration and follow-on treatment charged by Swedish dentists over a 10-11-year follow-up period. Furthermore, analyzing these fees with reference to the type of restoration, tooth group, and the root-filled teeth which survived compared to those requiring extraction.

Material and methods: In 2009, the data register of the Swedish Social Insurance Agency recorded a total of 215,611 teeth as root-filled. The accumulated fees for each tooth encompassed the following interventions: initial root filling, coronal restorations, and follow-up treatments during the designated period. The outcomes were analyzed using descriptive and analytic statistics, including t tests and one-way analysis of variance. The fees are presented in Euros (€1 = SEK 8.94).

Results: The total accumulated fees for root fillings amounted to 72 million Euros: the mean fee per root filled tooth was €333.6. The total mean fee over a 10-11-year period, comprising root canal treatment, coronal restorations, and any follow-up treatments, was €923.4. Root-filled teeth with indirect restorations presented a higher mean fee (€1 279.3) compared to those with direct restorations (€829.4) or those without specified restorations (€832.7; p < .001). Moreover, molars presented a significantly higher mean fee (€966.4) compared to premolars (€882.8) and anterior teeth (€891.3; p < .001). Lastly, the mean fee for extracted teeth was €1225.3, which was higher compared to those who survived the follow-up period (€848.0; p < .001).

Conclusions: Fees charged by general dental practitioners for root-filled teeth accumulate over time, probably due to the need for further treatment of the tooth. The total mean fee was significantly higher for molars and root-filled teeth with indirect restorations. However, an analysis of the total costs would require prospective clinical cost-effectiveness studies.

Aim: To investigate the fees for root filling and further dental care charged by Swedish dentists during a follow-up period of 10 to 11 years. Comparisons are made between type of restoration registered within 6 months of the root filling, the tooth group, and the root filled teeth that survived versus those that were extracted.Methods: A total of 215 611 teeth were registered as root filled in the Swedish Social Insurance Agency’s data register in 2009. For each identified tooth, the fees for the following interventions were tracked: initial root filling, coronal restorations, and further dental interventions registered during the follow-up period. The outcomes were analysed with descriptive and analytic statistics, using one-way ANOVA and t-tests. The fees are presented in Euro (€1 = SEK 8.94; 01/01/2012).Results: The total fee for the root fillings was 72 million euros, and the mean fee was €333.6 per root filling. The total mean fee for the preservation of a root filled tooth over 10 to 11 years was €923.4, which included root canal treatment, coronal restorations, and further interventions. The mean fee for indirectly restored root filled teeth was higher (€1 279.3) than for those directly restored (€829.4) and for teeth without specified restorations (€832.7; P < 0.001). Molars had a significantly higher mean fee (€966.4) compared to premolars (€882.8) and anterior teeth (€891.3; P < 0.001). The mean fee for teeth that were extracted was higher (€1 225.3) than for those that survived the follow-up (€848.0; P < 0.001). Conclusions: Fees for root filled teeth have accumulated over time probably due to further dental care needed. The total mean fee was significantly higher for indirectly restored root filled teeth than for directly restored. However, prospective clinical cost-effectiveness studies are needed to analyse the total costs.

Aim: To document treatment outcomes and related resources, in patients undergoing root canal treatment (RCT) in county public dental clinics, by monitoring patient records for 12 months from treatment start.

Methodology: The subjects comprised 243 patients starting RCT at 20 public dental clinics in Västra Götaland county, Sweden. Their computerized dental records were monitored prospectively for a year after starting their endodontic treatment. Treatment was completed with either a root filling or extraction. The following treatment-specific variables were registered: number of appointments and days until treatment was completed, possible complications and prescriptions for antibiotics, and for the root filled teeth: type of coronal restoration and further procedures undertaken within the year. The treatment outcomes were compared with the preoperative variables and in a logistic regression analysis.

Results: Complete data were available for 240 patients (98.8%): 128 women and 112 men, with a mean age of 48.5 years (SD = 16.3). Molar teeth predominated (n = 113, 47.1%). Most cases were completed with a root filling (n = 169, 70.4%). The remainder were extracted (n = 32, 13.3%) or were still uncompleted (n = 39, 16.3%). On average, a root filling was completed in 2.4 (SD = 0.9) appointments, or extraction at the third appointment (SD = 1.6). The molars were less often completed and often predominant among the extracted teeth. The indication for extraction was often for endodontic or RCT-related reasons. Most complications were registered in the molars and antibiotics were prescribed in 20 cases. Most root filled teeth were restored with a direct restoration. Four root filled teeth (2.4%) were extracted within the time period.

Conclusions: Patient records, followed from the start of treatment, show that 12 months on, the root filling had not been completed in just under 30% of the teeth. Of these, about half were extracted. Of particular concern is the outcome for endodontic treatment of molar teeth. In the general practice setting, molar endodontics are not only technically challenging but also very demanding in terms of chairside resources. In the present study, a successful outcome was achieved in just over half the cases.

Objectives: To evaluate the cost-effectiveness of root canal treatment (RCT) compared with a tooth extraction in a general dental practice setting, with reference to cost per quality-adjusted life-year (QALY) gained over 1 year.

Material and methods: This is a prospective controlled cohort study based on patients either starting RCT or undergoing extraction at one of six Public Dental Service clinics in the county of Västra Götaland, Sweden. From a total of 65 patients, 2 comparable groups were formed: 37 started RCT and 28 underwent extraction. A societal perspective was used for the cost calculations. QALYs were estimated, based on the EQ-5D-5L given to the patients at their first treatment appointment and then after 1, 6, and 12 months.

Results: The total mean cost of RCT ($689.1) was higher than for extraction ($280.1). For those patients whose extracted tooth was replaced, the costs were even higher ($1245.5). There were no significant intergroup differences in QALYs, but a significant improvement in health state values in the tooth-preserving group.

Conclusions: In the short term, extraction was cost-effective compared with preserving a tooth with RCT. However, the potential need for future replacement of the extracted tooth, by an implant, fixed prosthesis, or removable partial dentures, may change the calculation in favor of RCT.