Objective We aimed to compare subjective assessment of image quality and rater agreement of magnetic resonance (MR) images of the temporomandibular joint (TMJ) acquired with dental-dedicated 0.55 T and clinical 1.5 T magnetic field strengths. Study Design Six blinded raters evaluated randomized TMJ MR images from 5 healthy participants imaged with 3 pulse sequences on 2 scanners: a 0.55 T system using a custom-built surface coil for dental-dedicated applications and a clinical 1.5 T system using a standard head/neck coil. TMJ anatomy and image quality parameters were assessed using a three-point scale (0 = unacceptable, 1 = acceptable, and 2 = excellent). Data was pooled across participants, pulse sequences, and sides. Kappa coefficients were calculated for intra- and inter-rater agreement. Chi-square tests were applied to explore differences between scanners. Significance was established at P<0.05. Results Four different raters preferred 0.55 T images for visualizing hard and/or soft tissue anatomy (P≤.02). One rater preferred the 0.55 T system regarding contrast. No other differences were detected regarding qualitative ratings. Kappa values for intra-rater agreement ranged from 0.49 to 0.70 for 0.55 T images and 0.42 to 0.71 for 1.5 T images. Inter-rater kappa values ranged from 0.02 to 0.29 for 0.55 T images and 0.02 to 0.23 for 1.5 T images. Conclusions Images from the two systems were rated similarly. Further research is needed to assess diagnostic performance in patients.

The objective is to present a dental-dedicated magnetic resonance imaging (ddMRI)-based follow-up of inferior third molar removal over 12 months. A 30-year-old female presented with recurrent pain and bleeding from her lower right third molar. With adding diagnostic information from a panoramic image, the tooth was referred for removal. The patient underwent ddMRI using a dental coil with a proton density (PD) weighed turbo spin echo (TSE) sequence and a PD-TSE-STIR with fat suppression to highlight possible inflammatory processes. The scans were performed pre-operatively, immediately post-operatively, and in a rigorous follow-up (weekly basis for the first 6 weeks, bi-weekly from 7 to 12 weeks, and once at 6 and 12 months post-operatively). Using ImageJ software, circular ROIs were selected in the extraction alveolus coronary, middle, and apical regions. Mean grey values (MGVs) and standard deviation (SD) were obtained. A trend of decreasing MGVs in the PD (TSE) pulse sequence was observed over time, irrespective of the root third. Considering the PD-STIR (TSE), no trend was observed. ddMRI is feasible in the follow-up assessment of inferior third molar removal. Further clinical trials with larger samples are needed to define the usability of follow-up with ddMRI, considering a potential added diagnostic value.

Objectives: Early pre- clinical inflammatory changes in periodontal and/or periapical lesions, which typically precede bone loss, are challenging to diagnose using ionizing- radiation- based imaging modalities. MRI provides relevant additional diagnostic information of inflammatory processes in soft and hard tissues. The aim of the present study is to undertake a systematic review of the literature on MRI in the diagnosis of periodontal and/or periapical disease. Methods and Materials: The PubMed/MEDLINE and Scopus bibliographic databases were searched (2000-2021) using the search string: ("MRI" or "magnetic resonance imaging") and ("periodontitis" or "periodontal" or "apical pathology" or "endodontic pathology" or "periapical" or "furcation" or "intrabony"). The search was limited to studies published in English. The studies were assessed independently by three reviewers, focusing on the MRI sequences, imaging modalities (radiographs, cone beam CT (CBCT), and MRI), disease definition, assessed parameters, and outcome measurements. Results: The search strategy yielded 34 studies, from which 13 were included. Overall, the findings of MRI were in agreement with CBCT. The studies showed that MRI provided diagnostic information of the hard and soft tissue components affected by periodontal and/or periapical disease with a fairly high sensitivity and specificity. However, the assessed parameters (e.g. MRI acquisition protocols, and disease definition) differed substantially. Conclusions: The included studies indicate that the use of MRI in the diagnosis of periodontal and/or periapical disease is feasible and promising. More studies are needed to define the accuracy of this non- ionizing- radiation- based diagnostic modality, in the assessment of periodontal and/or periapical lesions.

AIM To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens. MATERIAL AND METHODS Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type. RESULTS ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001). CONCLUSION Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.

ObjectivesDiagnostic imaging is crucial for implant dentistry. This review provides an up-to-date perspective on the application of digital diagnostic imaging in implant dentistry.MethodsElectronic searches were conducted in PubMed focusing on the question 'when (and why) do we need diagnostic imaging in implant dentistry?' The search results were summarised to identify different applications of digital diagnostic imaging in implant dentistry.ResultsThe most used imaging modalities in implant dentistry include intraoral periapical radiographs, panoramic views and cone beam computed tomography (CBCT). These are dependent on acquisition standardisation to optimise image quality. Particularly for CBCT, other technical parameters (i.e., tube current, tube voltage, field-of-view, voxel size) are relevant minimising the occurrence of artefacts. There is a growing interest in digital workflows, integrating diagnostic imaging and automation. Artificial intelligence (AI) has been incorporated into these workflows and is expected to play a significant role in the future of implant dentistry. Preliminary evidence supports the use of ionising-radiation-free imaging modalities (e.g., MRI and ultrasound) that can add value in terms of soft tissue visualisation.ConclusionsDigital diagnostic imaging is the sine qua non in implant dentistry. Image acquisition protocols must be tailored to the patient's needs and clinical indication, considering the trade-off between radiation exposure and needed information. growing evidence supporting the benefits of digital workflows, from planning to execution, and the future of implant dentistry will likely involve a synergy between human expertise and AI-driven intelligence. Transiting into ionising-radiation-free imaging modalities is feasible, but these must be further developed before clinical implementation.

Objectives To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. Material and methods Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). Results Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p <= .05 for both observers). Mean measurement differences were not larger than the method error. Conclusion ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.

Objectives Dental materials, including orthodontic appliances and implants, are commonly mentioned as a possible source of artefacts in magnetic resonance imaging (MRI). The aim of the present study was to undertake a systematic review of the relevant literature on MR image artefacts due to dental materials, limited to orthodontic appliances and implant-supported dental prosthesis, on both technical and diagnostic levels. Methods The MEDLINE (PubMed) bibliographic database was searched up to September 2020. The search was limited to studies published in English, using the search string: (MRI or magnetic resonance) and (artefact or artifact) and (dental or ortho or implant or restoration or restorative). The studies were assessed independently by three reviewers, focusing on the following parameters: MRI sequences, tested materials, assessed parameters, efficacy level and outcome. Results The search strategy yielded 31 studies, which were included in this systematic review. These studies showed that metallic dental materials, commonly present in orthodontic appliances and implant-supported dental prosthesis led to diverse types/severities of artefacts in MR images. Fifteen studies were in vivo, based on human subjects. The studies differed substantially in terms of tested materials, assessed parameters, and outcome measurements. Conclusions Metallic dental materials cause artefacts of diverse types and severities in MR images of the head and neck region. However, the diagnostic relevance of the investigated artefacts for the diverse MRI applications is yet to be studied.

Purpose: To undertake a systematic literature review of magnetic resonance imaging (MRI) employed in the three phases of implant-based oral rehabilitation: planning, execution, and follow-up. Materials and Methods: MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to January 2020 for studies assessing the use of MRI alone or in connection with CT and/or CBCT in the planning, execution, or follow-up of dental implant placement and/or bone grafting procedures in the maxilla or the mandible. Included studies were also assessed according to the diagnostic imaging efficacy scale presented by Fryback and Thornbury (F&T). Results: The search strategy yielded 10 studies, which were included in the systematic review. Six studies focused on the implant planning phase, one on the immediate followup phase, and three on both planning and follow-up. No studies acquired signal from the bone. There was no consensus on the gold standard, MRI sequence, or field strength (T). One study reached F&T level 1, eight reached level 2, and one reached level 3. Conclusion: The possible transition from radiography to ionizing-radiation-free imaging through MRI is still a novelty in dentistry and has yet to establish itself as a viable imaging modality suitable for replacing CT and CBCT. More studies are needed on the accuracy of the diverse MRI possibilities when applied for implant planning, execution, and follow-up before this diagnostic method can be considered as a reality for the clinician.

OBJECTIVES:To assess the frequency and characteristics (number, complexity, and distance) of head movements, and the perception of discomfort during simulated CBCT examinations in children, considering units with different patient positioning method and head immobilization device combinations.METHODS:Forty children (20 boys/20 girls, age range 10-14 years) were video-recorded during simulated CBCT examinations. Children were randomly allocated to a sequence of five CBCT units: Newtom-5G, Orthophos-SL, Cranex-3Dx (patient standing/sitting), and X1. The child scored his/her discomfort perception (visual scale) and the preferred/ill-favored unit. Three observers scored the videos (20% in duplicate): child movement (yes/no), number (<3/≥3/continuous), complexity (uniplanar/multiplanar) and distance (<3 mm/≥3 mm). κ statistics provided intra-/interobserver reproducibility. Severe/extreme motion was defined based on movement characteristics. Chi-square tests assessed the frequency differences of severe/extreme motion among the units, age and operator. Logistic regression analyses with severe/extreme motion as outcome were performed.RESULTS:The range of intra- and inter-observer reproducibility for movement observation was 0.78-0.89 and 0.61-0.64, respectively. Between 60% (Newtom-5G) and 100% (X1) of children moved during the examination. Severe/extreme motion was significantly related to unit and age. There was significantly less severe/extreme motion, when the child was in the supine position with a foam headrest as head support. The younger the child, the higher the risk for severe/extreme motion. The majority of the children preferred the unit with the supine position and a foam headrest.CONCLUSIONS:The prevalence of severe and extreme motion was associated with the unit's patient positioning method and head immobilization devices combined, and child age.

PURPOSE:Assess the radiographic peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone and classify the long-term (at least >4 ≤ 6 years) implant success according to two predefined sets of criteria.MATERIAL AND METHODS:Sixty patients had full maxillary alveolar reconstructions using autogenous bone grafts (iliac crest), and 369 titanium implants were installed. The follow-up protocol was 5 (>4 ≤ 6) years; thereafter only patients who presented significant peri-implant bone loss were followed up to 12 years. The radiographic peri-implant bone level was assessed on panoramic radiographs in relation to the baseline and used to classify the long-term success of the implants according to the predefined success criteria presented by Albrektsson and coworkers (ALB; 1986) and the Pisa Consensus Conference (PCC; 2007).RESULTS:Fifteen implants were lost over the 12-year follow-up period (two up to >4 ≤ 6 years). Mean radiographic peri-implant bone loss was 2.7 mm at the >4 ≤ 6 years control and 4.2 mm after >11 ≤ 12 years. Different success criteria resulted in different types of prevalence of implants classified as "failures." At >4 ≤ 6 years, 48% of the implants would be "failures" according to ALB, while according to the PCC, only 0.8% would be "failures" and 18.1% would be classified as "compromised survival" and 44.8% as "satisfactory survival."CONCLUSIONS:Mean peri-implant bone loss of implants installed in maxillary areas grafted with autogenous bone blocks was 2.7 mm after >4 ≤ 6 years, and two implants were lost during this period. The use of different success criteria significantly altered the prevalence of implants classified as "failure."

OBJECTIVES:The aim of this study was to assess the prevalence and severity of image-stitching artifacts in charge-coupled device (CCD)-based cephalograms and their relationship to patient age. STUDY DESIGN:Cephalograms from 200 patients, acquired by using 2 Promax 2-D units (100 images using Dimax-3 [D-3] and 100 using Dimax-4 [D-4] sensors) were examined. Three observers assessed the presence and severity of image-stitching artifacts for stitching line visibility in 3 categories (none or almost invisible, thin, and thin with vertical stripes or thick) and misalignment between the anatomic structure display in 4 categories (none, <1 mm, 1-3 mm, and >3 mm). Severe artifacts were defined as a stitching line that was thin with vertical stripes or thick, and misalignment ≥1 mm. Patients were grouped by age: ≤13, 14-20, and >20 years old. Observer agreement was assessed by using Kappa statistics. Artifact prevalence and severity were calculated for both sensor types. The effect of age on the presence of severe artifacts was assessed. RESULTS:Stitching lines were observed in 86.7% of D-3 images and 3.3% of D-4 images. Young age had a significant effect on the presence of severe artifacts in D-3 images. CONCLUSIONS:Sensor type and patient age have substantial effects on the prevalence and severity of image-stitching artifacts in CCD-based cephalograms.

BACKGROUNDAn enduring clinical question concerns the outcome (ie, success) of implants placed in areas grafted with block-grafts.OBJECTIVETo undertake a systematic review of the literature on the long term results (≥5 years) of implants placed in maxillofacial areas grafted with any type of osseous block-grafts in two-stage surgeries. Further, the review addresses how available success criteria were used within the studies.MATERIALS AND METHODSThe MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to March 2017 for studies evaluating the long term results of implants placed in grafted areas. The search strategy was restricted to English language publications using combined terms which referred to the treatment method (implants placed in areas grafted with bone blocks), and follow-up characteristics (≥5 years and assessment of at least one parameter related to implant success criteria). To qualify for inclusion, studies should present outcome measurements indicating the success (or at least the survival) of the implants.RESULTSThe search strategy yielded 17 studies, which were included in this systematic review. These studies presented survival rates ranging from 88.7% (after 15 years follow-up) to 98.7% (after 5 years follow-up). Five studies presented data based on predefined success criteria with success rates ranging from 86.8% to 100%. In these studies, the term "success" was often not properly defined.CONCLUSIONThe long term survival (≥5 years) of implants placed into block-grafted areas in two-stage surgeries was not lower than 75%, while success rates ranged from 86.8% to 100%. Although it was possible to identify published success criteria for implant follow-up, there is no broad consensus on how to report implant success in a consistent manner.