Radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using two different root canal irrigants. A prospective cohort study.

AIM: The aim of this prospective cohort study was to compare the radiographic outcome of endodontic treatment and retreatment of teeth with apical periodontitis using either 1% sodium hypochlorite (NaOCl) or 2% chlorhexidine digluconate (CHX) for root canal irrigation. MATERIALS AND METHODS: In the years from 2013 to 2015 standard irrigation varied by semester between NaOCl and CHX at the Department of Endodontics at the Faculty of Dentistry. During that time, 912 teeth received treatment for apical periodontitis in 744 patients, of whom 532 responded to the request for a 1-year follow-up. Only one tooth per person (the most distally located) were included; 285 teeth treated with NaOCl and 247 with CHX. One hundred cases were then randomly sampled from each irrigation group and analysed for outcome by periapical index (PAI) scoring using criteria for success, uncertain and failure. Clinical and other radiographic parameters were scored or recorded and analysed for associations with radiographic outcome using chi-square, ANOVA and regression analyses. RESULTS: Success rates (PAI score 1 or 2 at control) were nearly identical for the two irrigation liquids. The use of irrigating solution also did not significantly influence the outcome in chi-square analyses of subgroups of teeth or regression analyses with other variables included. Ordinal regression analysis established that preoperative lesion size or preoperative PAI score were significantly associated with outcome, and teeth in the mandible had significantly better outcomes than in the maxilla. CONCLUSIONS: No significant differences in the radiographic outcome using either 1% NaOCl or 2% CHX as irrigants were found. The outcome was better for teeth with small lesions or lower PAI scores at completion of treatment and for mandibular teeth.

Students' perceptions of post-exam feedback in oral radiology-A comparative study from two dental hygienist educational settings.

INTRODUCTION: The aim of this study was to investigate how students perceive the benefit of participating in a teacher-organised session providing feedback on exams, termed post-exam feedback, in two dental hygienist programmes. METHODS: The study was based on interviews with 22 participants, including 18 students and 4 faculty teachers. The data were approached on the basis of thematic analysis, allowing us to generate insights on how the participants reflected on their participation in the post-exam feedback sessions and how they perceived this arrangement as learners. RESULTS: The findings from the study suggest that motivated students consider post-exam feedback to be beneficial in clearing up uncertainties and deepening their understanding of issues not fully understood during the exam, as well as supporting their further learning. Less motivated students mainly consider post-exam feedback to be relevant for students who do not pass the exams. CONCLUSIONS: Organised in a student-centred way and with attentiveness to student learning preferences, the results suggest that post-exam feedback can be valuable for enhancing assessment and supporting student learning related to exams.

Five-year radiological findings from a randomized controlled trial of four periodontitis treatment strategies.

Radiographic findings from long-term studies of periodontitis treatment have rarely been reported. Although bone destruction is a prominent feature of periodontitis, the long-term effect on alveolar bone levels of different treatment strategies, with or without adjunctive metronidazole (MTZ), has not been reported. We investigated the 5-year radiographic outcome of therapy in patient groups treated with conventional scaling and root planing (SRP) or same-day full-mouth disinfection (FDIS), with or without adjunctive MTZ. Following a 3-month oral hygiene phase, 184 periodontitis patients were randomly allocated to one of four treatment regimens: (i) FDIS+MTZ; (ii) FDIS+placebo; (iii) SRP+MTZ; or (iv) SRP+placebo. Following active treatment, patients received biannual maintenance. In total, 161 patients (87.5%) completed the 5-year follow-up examination, at which the radiographic bone level (RBL), clinical attachment level, probing pocket depth, presence of plaque, and bleeding were recorded again. At the 5-year follow up examination, minor radiological bone loss was observed in the intervention groups FDIS+placebo, SRP+MTZ, and SRP+placebo; by contrast, the FDIS+MTZ group did not show any change in RBL. Full-mouth disinfection did not generally perform better than conventional SRP performed over a period of 2 to 4 weeks.

The use of post-exam feedback in oral radiology: A survey study of dental and dental hygienist schools in Europe.

INTRODUCTION: A combination of summative assessments and post-exam feedback can create a formative environment to support student learning. It remains unknown to what extent feedback sessions are conducted after exams in oral radiology courses for dental and dental hygienist students in Europe. This survey study aimed to explore whether post-exam feedback sessions were conducted, and if so, in what format. MATERIALS AND METHODS: A questionnaire was distributed to 76 dental schools in 26 countries and 34 dental hygienist schools in 14 countries in Europe. The questions addressed whether feedback was provided after exams in oral radiology, the feedback format, and whether feedback sessions were formalised or performed for other reasons. RESULTS: Questionnaire responses were received from 33 dental schools in 18 countries, and 20 dental hygienist schools in 11 countries. Information about grades was provided in 23-30% of the schools. Post-exam feedback sessions including opportunities for discussion was provided at 39% of the schools, all with guidelines stating that these sessions should be carried out. The remaining schools provided feedback either on request by individual students or as written examples of correct answers. CONCLUSION: Almost one third of the dental schools announced grades without providing any post-exam feedback that could support learning. Two fifth utilised feedback sessions to assist students in gaining knowledge and sorting out misconceptions, all according to guidelines. Given the possible learning potential in post-exam feedback with opportunity to discuss, further studies of this format would be valuable, including the role and use of feedback guidelines.

Teaching Radiographic Caries Detection and Treatment Planning: A Seminar Using an Audience Response System.

This study presents a seminar model for teaching radiographic caries detection and treatment planning at the Faculty of Dentistry, University of Oslo. The seminar is based partly on an audience response system (ARS) and uses patient cases to focus on caries risk assessment and treatment planning. This paper describes the seminar design, implementation, learning outcomes, and observational study of variability in caries registrations and students' attitudes to use of ARS. Dental and dental hygiene students participate in two seminar modules. Module 1 aims to develop and increase individual student skills in radiographic caries lesion detection, scoring, and differential diagnosis. Students perform trial registrations on bitewings using an ARS with anonymous live polling, and scorings are discussed in plenum. Students then perform individual registrations on 12 bitewing pairs. Using digital scoring, students detect and grade caries lesions on all approximal and occlusal tooth surfaces. After the session, students use the ARS to repeat scorings on selected tooth surfaces, and results are again discussed in plenum. Module 2 involves group exercises on 4 patient cases that are later presented with plenary discussions. In total, 1,624 caries registrations performed by 150 students attending the seminar between 2016 and 2018 were assessed for variability between students. As expected, variations in caries registrations were observed between students, mostly related to restored surfaces or tooth surfaces that were otherwise difficult to register. In 2022, 63 dental and dental hygiene students attending the seminar answered a questionnaire about use of ARS. The responses were scored using a five-point Likert scale. Overall, no significant difference in satisfaction with the ARS-based module was observed between dental and dental hygiene students (χ2 test, p > 0.05). The majority of the students were positive toward the use of ARS (94%), but some disagreed on the role of ARS in usefulness for understanding the seminar content (3.2%), and in increasing their confidence in radiographic registration of caries (3.2%). The ARS-based module provides a positive learning environment that ensures student anonymity, interactivity, and engagement, and combined with the other seminar module gives students basic skills in caries detection and treatment planning.

Effects of an individualized training course on technical quality and periapical status of teeth treated endodontically by dentists in the Public Dental Service in Norway: An observational intervention study.

AIM: To investigate the effect of a continuing education course on technical quality and treatment outcome for root filled permanent teeth in Møre and Romsdal County, Norway. METHODOLOGY: Fifty-two dentists employed in the Public Dental Service in Møre and Romsdal county, Norway, completed a two-day continuing education course in root canal treatment. Periapical radiographs of root filled teeth treated before and after the course, with at least one-year follow-up were identified and scored for technical quality and periapical status. Technical root filling quality was assessed by density and length and the treatment outcome by PAI scores. Treatment information was achieved from the county's electronic dental record system. Information regarding the dental practitioners' background and treatment procedure routines was collected by a questionnaire. Descriptive statistics analyses and mixed-effect logistic regression analyses were performed to evaluate the effect of the course. RESULTS: Radiographs were available for 224 teeth root filled before and for 221 teeth after the course. The proportion of teeth with adequate root filling quality was significantly lower after the course (p = .006), associated mainly with short root fillings (p < .001). No significant differences were observed in treatment outcome. There were, however, large differences in treatment outcome amongst subgroups of dentists. Further, there was evidence of effect modification by the continuing education course on periapical outcome by patient's age (pinteraction  = .0023) suggesting that teeth in patients ≤18 years healed relatively better post-course compared to patients >18 years. CONCLUSIONS: A two-day continuing education course in root canal treatment attended by Public Dental Service dentists in Norway did not improve the technical quality of root fillings or periapical status associated with root filled teeth.

Digitalised exercise material in forensic odontology.

INTRODUCTION: This paper presents digital educational material in forensic odontology, including dental identification after multiple fatalities and dental age estimation from different age groups. MATERIAL AND METHOD: Electronic patient records consisting of intraoral scans of the dentition, digital radiographs, photographs and written dental records were collected. Exercises in age estimations contained digital radiographs and photographs of ground tooth sections, with digital measuring tools and tables according to age groups. The teaching material was organised as a module in an electronic Learning Management System with external links to all relevant teaching material. RESULTS: For the identification exercises, intraoral scans and the latest digital radiographs simulated the postmortem examination of the deceased. For comparison, all other radiographs, photographs and dental records were available as antemortem material. The exercise was to match postmortem findings with the antemortem records using the Interpol standard and reconciliation. Age assessment of children used designated tables to grade tooth development on digital radiographs. For adults, non-destructive methods, digital radiographs, photographs and measuring tools were used. DISCUSSION: The teaching concept was hybrid, but it can easily be adapted as a fully digital exercise. The instructions and written material can be translated into different languages. The level of difficulty in the exercises can be adjusted according to the participant's level of knowledge. CONCLUSION: The educational material embraces the new possibilities for digitalisation and intraoral scanning. This might be a valuable tool for motivating and engaging the students in their participation and understanding of the subject.

Radiographic alveolar bone level and levels of serum 25-OH-Vitamin D3 in ethnic Norwegian and Tamil periodontitis patients and their periodontally healthy controls.

BACKGROUND: Studies suggest association between low serum 25-OH-Vitamin D3 (VitD) and chronic destructive periodontal diseases. The main sources of VitD is sun exposure and fat fish. Subjects with dark skin will therefore generate less VitD as response to sun exposure. The aim of the study was to assess the radiographic bone level and levels of serum VitD in ethnic Norwegian and Tamil periodontitis patients and their respective healthy controls. METHODS: Twenty-seven Tamil periodontitis patients living in Norway were compared to 21 Tamil controls as well as to 21 Norwegian periodontitis patients and 23 Norwegian controls. Marginal bone level was diagnosed on radiographs. VitD levels were diagnosed in blood samples by high-performance liquid chromatography-mass spectrometry. RESULTS: VitD levels were lower in Norwegian periodontitis patients than in controls, while no significant differences were observed between Tamil periodontitis patients and controls despite the significant difference between RBL between the periodontitis patients and controls in both groups. When calculating the odds ratio for having periodontal disease in both populations together, it appeared that one unit increased serum VitD (i.e. 1 nmol/L) decreased the odds of having radiographic bone loss by 4%. CONCLUSION: According to logistic regression, and after correcting for confounding factors, VitD levels showed significant association with the presence of periodontitis, as expressed by radiographic bone loss, in all patients combined.

Image quality assessment of clinically-applied CBCT protocols using a QAT phantom.

OBJECTIVES: This study has two main purposes: (1) to evaluate the effect of various clinically applied protocols [changing field of view (FOV), voxel size and tube voltage (kVp)] on CS 9300 CBCT (CareStream SM 749, Rochester, NY) image quality using its quality assurance test (QAT) phantom and (2) to evaluate the efficacy of a newly-designed prototype plugin on ImageJ (National Institutes of Health, Bethesda, MD) which was introduced to measure modulation transfer function (MTF) using a modified slanted-edge method. METHODS: Using a specifically constructed QAT phantom, five image quality parameters were assessed-image uniformity, signal-to-noise ratio, contrast, position checking and the MTF-for ten variables, clinically applied protocols on a CS 9300 PREMIUM three-dimensional CBCT device. RESULTS: With FOV and voxel size fixed, high-dose protocols resulted in less image noise and more uniformity. On the other hand, less image uniformity was achieved with less kVp. Moreover, high-dose protocols resulted in a high contrast-to-noise ratio (CNR). There were significant differences in CNR between 60 and 70 kVp as well as between 70 and 90 kVp. Our study identified no difference between MTF and either voxel size or FOV. CONCLUSIONS: The image quality of the CS 9300 CBCT varied with variability in exposure protocols and different voxel sizes. The negative association between greater spatial resolution (smaller voxel size) and the MTF shows that the slanted edge method is not ideal for MTF evaluation of CBCT and is therefore not recommended for using it for this purpose.

A new digital tool for radiographic bone level measurements in longitudinal studies.

BACKGROUND: The reproducibility of measurements on radiographs is influenced by the techniques by which the images as well as the measurements are obtained. Thus, bias resulting from errors in the image and/or image examinations at two points in time may result in wrongful registrations of true biological or pathological changes. The aim of the present study was to propose and evaluate an indirect radiological examination technique, by which bias, when measuring radiographic bone level, could be substantially reduced as compared to the technique using direct mm measurements. METHODS: A plugin to ImageJ was designed to reduce bias when measuring bone loss on radiographic images. In human dry mandibles, radiographic images of 20 teeth were obtained parallel with the tooth axis (alpha = 0) and at an angle of 30° deviation. The direct technique of measuring radiographic bone level (RBL) and the indirect, length-adjusted RBL were registered by four researchers in a double blinded fashion. RESULTS: When mean RBL measured at 0° angle was 7.0 mm, the corresponding mean RBL measured at 30° angle was 7.8 mm, signifying an 11.4% increase (p = 0.032), whereas the mean length-adjusted RBL increased by 0.6% (p = 0.9). CONCLUSIONS: This study showed that the use of the original, direct technique (ImageJ) resulted in markedly biased radiographic bone level at 30° angle, while the proposed indirect length-adjusted technique (ImageJ plugin) did not.

How do dentists use CBCT in dental clinics? A Norwegian nationwide survey.

OBJECTIVES: Cone beam computed tomography (CBCT) was introduced to Norwegian dental clinics in 2007. The aim of the study was to investigate how dental clinics use this imaging modality, including factors related to workflow and image quality, and to evaluate dentists' opinions on and experiences of using it. MATERIALS AND METHODS: A web-based 59-item questionnaire regarding the clinical use of CBCT was sent to all 39 CBCT clinics in Norway. RESULTS: Twenty-nine clinics (74%) responded. Most respondents (93%) were from clinics with more than one dentist and 83% had at least one specialist. All clinics had digital intraoral x-ray receptors and all but one had panoramic imaging. The most common indications for CBCT were implant treatment planning (34% of all clinics) and localization of impacted teeth (43% of specialist clinics). Seventy-two per cent of clinics reported an average of four or fewer CBCT examinations each week and 83% of respondents were subjectively satisfied with the image quality. The most commonly used enhancement functions were contrast (97%), brightness (90%) and zoom (86%). CONCLUSIONS: The Norwegian CBCT clinics surveyed were fully digitized and had multiple dentists. Periodontists and oral and maxillofacial surgeons were the most frequent specialties represented in the clinics. Clinics with only dental specialists performed more CBCT examinations/week than clinics with general practitioners or both general practitioners and specialists. The most common indications for CBCT examinations were related to treatment planning. This study found some challenges related to image quality and communication within the radiological team.

Comparison of Swedish and Norwegian Use of Cone-Beam Computed Tomography: a Questionnaire Study.

OBJECTIVES: Cone-beam computed tomography in dentistry can be used in some countries by other dentists than specialists in radiology. The frequency of buying cone-beam computed tomography to examine patients is rapidly growing, thus knowledge of how to use it is very important. The aim was to compare the outcome of an investigation on the use of cone-beam computed tomography in Sweden with a previous Norwegian study, regarding specifically technical aspects. MATERIAL AND METHODS: The questionnaire contained 45 questions, including 35 comparable questions to Norwegian clinics one year previous. Results were based on inter-comparison of the outcome from each of the two questionnaire studies. RESULTS: Responses rate was 71% in Sweden. There, most of cone-beam computed tomography (CBCT) examinations performed by dental nurses, while in Norway by specialists. More than two-thirds of the CBCT units had a scout image function, regularly used in both Sweden (79%) and Norway (75%). In Sweden 4% and in Norway 41% of the respondents did not wait for the report from the radiographic specialist before initiating treatment. CONCLUSIONS: The bilateral comparison showed an overall similarity between the two countries. The survey gave explicit and important knowledge of the need for education and training of the whole team, since radiation dose to the patient could vary a lot for the same kind of radiographic examination. It is essential to establish quality assurance protocols with defined responsibilities in the team in order to maintain high diagnostic accuracy for all examinations when using cone-beam computed tomography for patient examinations.

A phantom for simplified image quality control of dental cone beam computed tomography units.

OBJECTIVE: The purpose of this work was to develop an inexpensive phantom for simplified image quality assurance (IQA) together with algorithms for objective evaluation of image quality parameters and to integrate these components into an easy-to-use software package. This should help make quality control of dental cone beam computed tomography (CBCT) units accessible, easy, and affordable for any specialist or general practitioner. STUDY DESIGN: Our study developed an inexpensive polymethyl methacrylate (Plexiglas) phantom containing objects and structures for objective quantification of the most important image-quality parameters in CBCT imaging. It also paired the phantom with a software package, based on open-source software, for automatic processing and analysis. RESULTS: The software produces objectively measured IQA data for low- and high-contrast resolution, uniformity, noise characteristics, and geometric linearity. CONCLUSIONS: The authors consider the phantom and methods presented in this article to be a step toward helping clinical dental personnel perform regular quality assurance on CBCT units.