Do metal artifact reduction algorithms influence the detection of implant-related injuries to the inferior alveolar canal in CBCT images?

BACKGROUND: The routine application of dental implants for replacing missing teeth has revolutionized restorative and prosthetic dentistry. However, cone beam computed tomography (CBCT) evaluations of structures adjacent to the implants are limited by metal artifacts. There are several methods for reducing metal artifacts, but this remains a challenging task. This study aimed to examine the effectiveness of metal artifact reduction (MAR) algorithms in identifying injuries of implants to the inferior alveolar canal in CBCT images. METHOD: In this in vitro study, mono-cortical bone windows were created and the inferior alveolar canal was revealed. Using 36 implants, pilot drill and penetration damage of the implant tip into the canal was simulated and compared to the control implants with distance from the canal. CBCT images were evaluated by four experienced observers with and without the MAR algorithm and compared to direct vision as the gold standard. The values of accuracy, sensitivity, and specificity were obtained and compared by receiver operating characteristic (ROC) curve (α = 0.05). RESULT: The area under the ROC curve values for detection of pilot drill injuries varied between 0.840-0.917 and 0.639-0.854 in the active and inactive MAR conditions, respectively. The increase in ROC area was only significant for one of the observers (P = 0.010). For diagnosing penetrative injuries, the area under the ROC curve values was between 0.990-1.000 and 0.722-1.000 in the active and inactive MAR conditions, respectively. The improvement of ROC curve values in active MAR mode was only significant for one of the observers (P = 0.006). CONCLUSION: Activation of MAR improved the diagnostic values of CBCT images in detecting both types of implant-related injuries to the inferior alveolar canal. However, for most observers, this increase was not statistically significant.

Use of artificial intelligence software in dental education: A study on assisted proximal caries assessment in bitewing radiographs.

INTRODUCTION: Teaching of dental caries diagnostics is an essential part of dental education. Diagnosing proximal caries is a challenging task, and automated systems applying artificial intelligence (AI) have been introduced to assist in this respect. Thus, the implementation of AI for teaching purposes may be considered. The aim of this study was to assess the impact of an AI software on students' ability to detect enamel-only proximal caries in bitewing radiographs (BWs) and to assess whether proximal tooth overlap interferes with caries detection. MATERIALS AND METHODS: The study included 74 dental students randomly allocated to either a test or control group. At two sessions, both groups assessed proximal enamel caries in BWs. At the first session, the test group registered caries in 25 BWs using AI software (AssistDent®) and the control group without using AI. One month later, both groups detected caries in another 25 BWs in a clinical setup without using the software. The student's registrations were compared with a reference standard. Positive agreement (caries) and negative agreement (no caries) were calculated, and t-tests were applied to assess whether the test and control groups performed differently. Moreover, t-tests were applied to test whether proximal overlap interfered with caries registration. RESULTS: At the first and second sessions, 56 and 52 tooth surfaces, respectively, were detected with enamel-only caries according to the reference standard. At session 1, no significant difference between the control (48%) and the test (42%) group was found for positive agreement (p = .08), whereas the negative agreement was higher for the test group (86% vs. 80%; p = .02). At session 2, there was no significant difference between the groups. The test group improved for positive agreement from session 1 to session 2 (p < .001), while the control group improved for negative agreement (p < .001). Thirty-eight per cent of the tooth surfaces overlapped, and the mean positive agreement and negative agreement were significantly lower for overlapping surfaces than non-overlapping surfaces (p < .001) in both groups. CONCLUSION: Training with the AI software did not impact on dental students' ability to detect proximal enamel caries in bitewing radiographs although the positive agreement improved over time. It was revealed that proximal tooth overlap interfered with caries detection.

Distinct microbiome profiles in convergent wisdom tooth impactions.

AIMS: Long-term retention of impacted third molars (wisdom teeth) is associated with plaque stagnation and the development of caries on the adjacent surface of the neighboring second molar. While caries and tooth loss are common outcomes of impaction, there is currently insufficient evidence to support the pre-emptive removal of asymptomatic wisdom teeth. Emerging evidence suggests that convergently growing impactions are associated with caries. We have therefore investigated the composition of dental plaque on the distal surface of the mandibular second molar at various impaction angles. METHODS AND RESULTS: We have compared the microbiome of these surfaces at four impaction angulations using short-read sequencing of the bacterial 16S rRNA gene: two convergent (horizontal and mesial) and two divergent (distal and vertical) angulations, and in cases where the wisdom tooth is missing. Horizontal angulations exhibited lower microbial diversity than mesial impactions. Amplicon Sequence Variants (ASVs) associated with Veillonella were significantly more abundant at impactions with angulations toward the midline. Using machine learning, a random forest classifier trained to distinguish microbiome profiles was used to predict the native angulations for a subset of samples, with samples from the two convergent impactions estimated with the greatest accuracy. CONCLUSIONS: Differences in microbial diversity were apparent between caries-associated convergent (horizontal and mesial) impacted wisdom teeth, as well as greater abundances of Veillonella ASVs at horizontal impactions.

3D-printed nanocomposite denture base resin: The effect of incorporating TiO2 nanoparticles on the growth of Candida albicans.

PURPOSE: To develop a biocompatible denture base resin/TiO2 nanocomposite material with antifungal characteristics that is suitable for 3D-printing denture bases. MATERIALS AND METHODS: TiO2 nanoparticles (NPs) with a 0.10, 0.25, 0.50, and 0.75 weight percent (wt.%) were incorporated into a commercially available 3D-printed resin material. The resulting nanocomposite material was analyzed using Lactate dehydrogenase (LDH) and AlamarBlue (AB) assays for biocompatibility testing with human gingival fibroblasts (HGF). The composite material was also tested for its antifungal efficacy against Candida albicans. Fourier transform infrared (FTIR) and Energy Dispersive X-ray Spectroscopy (EDX) mapping were conducted to assess the surface coating and the dispersion of the NPs. RESULTS: LDH and AB assays confirmed the biocompatibility of the material showing cell proliferation at a rate of nearly 100% at day 10, with a cytotoxicity of less than 13% of the cells at day 10. The concentrations of 0.10, 0.25, and 0.50 wt.% caused a significant reduction (p < 0.05) in the number of candida cells attached to the surface of the specimens (p < 0.05), while 0.75 wt.% did not show any significant difference compared to the control (no TiO2 NPs) (p > 0.05). FTIR and EDX analysis confirmed the presence of TiO2 NPs within the nanocomposite material with a homogenous dispersion for 0.10 and 0.25 wt.% groups and an aggregation of the NPs within the material at higher concentrations. CONCLUSION: The addition of TiO2 NPs into 3D-printed denture base resin proved to have an antifungal effect against Candida albicans. The resultant nanocomposite material was a biocompatible material with HGFs and was successfully used for 3D printing.

Endocrowns Clinical Performance and Patient Satisfaction: A Randomized Clinical Trial of Three Monolithic Ceramic Restorations.

PURPOSE: The purpose of this randomized, double-blind, clinical trial was to assess the survival of endocrowns made from three different monolithic ceramic materials, and to evaluate patient satisfaction. MATERIALS AND METHODS: Fifty-three patients (sixty root canal treated molar teeth) were enrolled. Teeth were prepared to a flat butt-joint margin and randomly divided between three material groups: lithium disilicate-reinforced glass-ceramic, monolithic zirconia and polymer infiltrated hybrid ceramic. Predefined cementation protocols were used. Clinical assessment using modified United States Public Health Service (USPHS) criteria was carried out after two years by two independent clinicians blinded to the material used. Radiographic examination was conducted to check for the presence of caries, excess cement, and periapical infection. Statistical analysis was performed using the Kruskal Wallis and Wilcoxon signed-rank tests as well as the Kaplan-Meier survival estimate. RESULTS: Forty-eight patients were available for assessment after 2 years (recall rate 90.6%). The overall Kaplan-Meier survival estimate among all groups was 90.9% with no statistically significant difference between the groups (p = 0.17). Three zirconia endocrowns debonded after 9, 10 and 13 months (82.4% survival rate), while 2 hybrid ceramic endocrowns chipped/fractured (89.5% survival rate). Lithium disilicate endocrowns had a 100% survival rate. The Kruskal Wallis test revealed no statistically significant difference between the groups in the USPHS criteria ratings and the radiographic assessment (P>0.05). Patient satisfaction ranged from 82.3% in the zirconia group to 100% in both the lithium disilicate and hybrid ceramic groups. CONCLUSIONS: Endocrowns provide a predictable option for the restoration of endodontically treated molar teeth in the short term. Lithium disilicate-reinforced ceramic had fewer complications and required less intervention compared with zirconia and hybrid ceramics. Long-term follow-up is required to substantiate these study results.

Methodological Quality of Systematic Reviews Relating to Performance of All-Ceramic Implant Abutments, Frameworks, and Restorations.

PURPOSE: To assess the methodological quality of published systematic reviews relating to all ceramic implant frameworks, abutments and restorations. MATERIALS AND METHODS: Published systematic reviews relating to all ceramic implant restorations for single tooth and multiple teeth replacements were retrieved to assess their methodological qualities. Sixteen systematic reviews were included for methodological quality assessment by two independent assessors using AMSTAR-2 critical appraisal tool. Inter-rater agreement was assessed using the weighted Cohen's Kappa statistic. RESULTS: Most systematic reviews included randomized clinical trials and nonrandomized studies of intervention. The majority of included systematic reviews (15 out of 16) scored critically low on quality with more than one critical flaw when assessed using the AMSTAR-2 tool. Most systematic reviews assessed lacked analysis of the effects of the risk of bias and heterogeneity of the included studies. The inter-rater agreement of the independent assessors was substantial (0.63). CONCLUSIONS: Confidence in the evidence presented in these systematic reviews was undermined by their tendency to overlook the effect of risk of bias and heterogeneity in evidence synthesis.

Osteoporosis risk assessment in primary dental care-The attitudes of Swedish dentists, patients and medical specialists.

OBJECTIVE: To explore and identify the attitudes of dentists, patients and medical specialists regarding implementation of osteoporosis risk assessment into Swedish primary dental care. BACKGROUND: Osteoporosis is a major health problem leading to fragility fractures. As shown in academic-based research, dental radiological examination can be used for osteoporosis risk assessment. A substantial number of patients undergo radiographic examinations in primary dental care each year, but little is known about implementation of osteoporosis risk assessment in this setting. MATERIALS AND METHODS: A qualitative research approach using focus group discussions and manifest content analysis was applied. Five focus groups with dentists and representatives from patient support groups and a single individual interview with one medical specialist were included in the sample. RESULTS: From the manifest content analysis, three categories emerged: (a) barriers to change in practice, (b) benefits to change in practice, and (c) needs and requirements prior to change in practice. Most participants felt that there was insufficient knowledge of osteoporosis as well as a heavy existing workload. A concern was expressed about medical practitioners' willingness to take on responsibility for patients referred by dentists. Representatives from patient support groups highlighted a lack of knowledge about osteoporosis among both the general public and the medical professionals. Clear guidelines and improved communication channels between stakeholders would have to be established to ensure a smooth treatment path for patients. CONCLUSION: Despite interest in osteoporosis risk assessment in primary dental care, there are political, workflow and educational barriers that must be overcome for successful implementation.

Micron-scale crack propagation in laser-irradiated enamel and dentine studied with nano-CT.

OBJECTIVES: The aim of this study was to see the effect of Er:YAG laser irradiation in dentine and compare this with its effect in enamel. The mechanism of crack propagation in dentine was emphasised and its clinical implications were discussed. MATERIALS AND METHODS: Coronal sections of sound enamel and dentine were machined to 50-µm thickness using a FEI-Helios Plasma (FIB). The specimen was irradiated for 30 s with 2.94-µm Er:YAG laser radiation in a moist environment, using a sapphire dental probe tip, with the tip positioned 2 mm away from the sample surface. One of the sections was analysed as a control and not irradiated. Samples were analysed using the Zeiss Xradia 810 Ultra, which allows high spatial resolution, nanoscale 3D imaging using X-ray computed tomography (CT). RESULTS: Dentine: In the peritubular dentine, micro-cracks ran parallel to the tubules whereas in the inter-tubular region, the cracks ran orthogonal to the dentinal tubules. These cracks extended to a mean depth of approximately 10 µm below the surface. On the dentine surface, there was preferential ablation of the less mineralised intertubular dentine, and this resulted in an irregular topography associated with tubules. Enamel: The irradiated enamel surface showed a characteristic 'rough' morphology suggesting some preferential ablation along certain microstructure directions. There appears to be very little subsurface damage, with the prismatic structure remaining intact. CONCLUSIONS: A possible mechanism is that laser radiation is transmitted down the dentinal tubules causing micro-cracks to form in the dentinal tubule walls that tend to be limited to this region. CLINICAL RELEVANCE: Crack might be a source of fracture as it represents a weak point and subsequently might lead to a failure in restorative dentistry.

Can mandibular bone resorption predict hip fracture in elderly women? A systematic review of diagnostic test accuracy.

OBJECTIVES: The aim of this systematic review was to determine the diagnostic accuracy of the mandibular cortical width measurements and porosity in detecting hip osteoporosis. BACKGROUND: All of the included studies used measurements on panoramic radiographs. MATERIALS AND METHODS: Studies were included if they compared the radiographic measurements (or index tests) with central dual energy X-ray absorptiometry (DXA) of the hip as the reference standard. A measure of diagnostic accuracy such as sensitivity and specificity or area under the receiver operating characteristic curve was also required for inclusion. RESULTS: Seven studies were identified. Meta-analysis was not possible because of the heterogeneity of the studies. The studies all demonstrated moderate diagnostic accuracy. CONCLUSION: If a patient with a thin or porous mandibular cortex is identified by a chance radiographic finding, additional clinical risk factors need to be considered and the patient referred for further investigation with DXA where necessary.

Do Implant Coatings Affect Healing of Placed Implants? An Umbrella Review.

PURPOSE: To analyze the available evidence and assess the effect of different implant coatings on healing outcomes. MATERIALS AND METHODS: Using the PICOS strategy, a structured question was formed. A protocol was agreed upon and registered with PROSPERO (no. CRD42022321926). The MEDLINE, Embase, Cochrane Database of Systematic Reviews, Scopus, Web of Science, Pubmed, and ScienceDirect databases were searched using a structured strategy. Study selection was independently carried out in duplicate, first by title and abstract, then by full-text assessment. Quality and risk of bias were independently assessed in duplicate using AMSTAR 2 and ROBIS. Data extraction was independently undertaken in duplicate using a predefined extraction form. RESULTS: The search yielded 11 systematic reviews for inclusion. The most commonly assessed coatings were based on calcium phosphate-including hydroxyapatite (HA), brushite, and bioabsorbable nano-HA-followed by bisphosphonate, then bioactive glass coatings. Included reviews most frequently assessed marginal bone loss (MBL), bone-to-implant contact (BIC), and survival/success rates. There was considerable heterogeneity and small sample sizes. The quality assessment suggested low confidence in the reviews and high risk of bias. CONCLUSIONS: The included reviews provide weak evidence that implant coatings improve osseointegration and reduce MBL following implant placement. There was weak evidence for progressive complications for calcium phosphate coatings. Further research and long-term multicenter controlled clinical trials with improved standardization and control of bias are required to better understand the effects of coating implants.

Impact of Artificial Aging on the Physical and Mechanical Characteristics of Denture Base Materials Fabricated via 3D Printing.

Three-dimensional (3D) printing is becoming more prevalent in the dental sector due to its potential to save time for dental practitioners, streamline fabrication processes, enhance precision and consistency in fabricating prosthetic models, and offer cost-effective solutions. However, the effect of aging in artificial saliva of this type of material has not been explored. To assess the physical and mechanical properties of the two types of 3D-printed materials before and after being subjected to artificial saliva, a total of 219 acrylic resin specimens were produced. These specimens were made with two types of 3D-printed materials, namely, NextDent (ND) and Formlabs (FLs), and a Schottlander heat-cured (HC) resin material that was used as a control. Water sorption and solubility specimens (n = 5) were tested after three months of storage in artificial saliva. Moreover, the Vickers hardness, Martens hardness, flexural strength/modulus, and impact strength were evaluated both under dry conditions and after three months of storage in artificial saliva. The degree of conversion (DC), elemental analysis, and filler content were also investigated. The ANOVA showed that 3D-printed resins had significantly greater sorption than the control group (p < 0.05). However, the flexural strength values of the 3D-printed materials were significantly greater (p < 0.05) than those of the heat-cured material. The DC of the 3D-printed resins was lower than that of the control group, but the difference was not significant (p > 0.05). The 3D-printed materials contained significantly more filler than the control (p < 0.05). Moreover, the artificial saliva had a significant effect on the Vickers hardness for all tested groups and on the Martens hardness for the control group only (p < 0.05). Compared with conventional heat-cured materials, 3D-printed denture base materials demonstrated relatively poorer performance in terms of sorption, solubility, and DC but exhibited either comparable or superior mechanical properties. The aging process also influenced the Vickers and Martens' hardness. The strength of the 3D-printed materials was in compliance with ISO recommendations, and the materials could be used alongside conventional heat-cured materials.

Soft tissue simulant materials in X-ray-based imaging in dentomaxillofacial radiology: a scoping review.

INTRODUCTION: In in-vitro dental radiographic research, simulation of soft tissue is required to replicate the clinical condition as close as possible. This study aimed to find out which soft tissue simulation material have been studied to use in dentomaxillofacial radiology and showed similarity in radiodensity to the soft tissues of the maxillofacial region. METHODS: In this scoping review, Web of Science, Embase, Scopus, Google scholar and PubMed databases were searched on April 9, 2023, considering the following PICOS: Population: soft tissue simulants, Intervention: X-ray-based imaging, Comparison: -, Outcome: properties of the soft tissue simulants, Study design: in-vitro studies. Screening, study selection, and data extraction were performed by two independent researchers. A third team member was consulted in the case of disagreement. Quality assessment of the included studies was made using Quality Assessment Tool For In-Vitro Studies (QUIN Tool). RESULTS: Of the initial 1172 articles retrieved in the database search, 13 studies were included in the review. Seven studies had a low risk of bias. In 8 studies, computed tomography (CT) or cone beam computed tomography (CBCT), in 4 studies intraoral radiography, and in 2 studies panoramic radiography was used (one study has used CT/CBCT and panoramic radiography). The studies varied in the radiographic modality, acquisition parameters, selected outcomes, and gold standard. In the majority of the studies (n = 10, 77%), acrylic resin derivatives were used in the soft tissue simulant formula alone or as a major component. Wax was used in the simulant material in 8 studies (62%). In addition, in 3 studies (23%) ice/water was used as the main simulant. CONCLUSION: Ballistic gelatin, expanded 2-cm thick polystyrene with or without 1-cm utility wax, and 0.5 cm of acrylic resin were shown to have a radiographic density similar to soft tissue in standardized studies employing CBCT scanning. For intraoral radiographs, using self-polymerizing acrylic resin, utility wax, and wood, as well as a polymethylmethacrylate box filled with water in thicknesses ranging from 4 to 45 mm, provides suitable radiographic contrast. However, for 4 and 8 mm of wax and 4 mm of water, the radiographic contrast is not appropriate. In addition, 13-17 mm wax and 14.5 mm acrylic resin showed acceptable soft tissue densities in intraoral radiography. Further studies using different imaging modalities with standardized conditions and objective metrics are required to confirm the most appropriate soft tissue simulant material for in-vitro dental radiographic research.

A historical review of 'phossy jaw'.

The aim of this article is to stimulate interest and discussion on the pathogenesis of 'phossy jaw'. Historical evidence from newspapers and articles of the time is presented, as other scientific evidence is largely absent. It has stimulated considerable interest in present-day media due to the struggles of nineteenth century reformers to improve working conditions against an apathetic government and weak enforcement of regulation. Those afflicted were often young women who suffered severe pain, loss of segments of jaw, and disfigurement.

3D printed denture base material: The effect of incorporating TiO2 nanoparticles and artificial ageing on the physical and mechanical properties.

OBJECTIVES: To evaluate the physical and mechanical properties of three-dimensional (3D) printed denture base resin incorporating TiO2 nanoparticles (NPs), subjected to a physical ageing process. METHODS: Acrylic denture base samples were prepared by a Stereolithography (SLA) 3D printing technique reinforced with different concentrations (0.10, 0.25, 0.50, and 0.75) of silanated TiO2 NPs. The resulting nanocomposite materials were characterized in terms of degree of conversion (DC), and sorption/solubility flexural strength, impact strength, Vickers hardness and Martens hardness and compared with unmodified resin and conventional heat-cured (HC) material. The nanocomposites were reassessed after subjecting them to ageing in artificial saliva. A fractured surface was studied under a scanning electron microscope (SEM). RESULTS: The addition of TiO2 NPs into 3D-printed resin significantly improved flexural strength/modulus, impact strength, Vickers hardness, and DC, while also slightly enhancing Martens hardness compared to the unmodified resin. Sorption values did not show any improvements, while solubility was reduced significantly. The addition of 0.10 wt% NPs provided the highest performance amongst the other concentrations, and 0.75 wt% NPs showed the lowest. Although ageing degraded the materials' performance to a certain extent, the trends remained the same. SEM images showed a homogenous distribution of the NPs at lower concentrations (0.10 and 0.25 wt%) but revealed agglomeration of the NPs with the higher concentrations (0.50 and 0.75 wt%). SIGNIFICANCE: The outcomes of this study suggested that the incorporation of TiO2 NPs (0.10 wt%) into 3D-printed denture base material showed superior performance compared to the unmodified 3D-printed resin even after ageing in artificial saliva. The nanocomposite has the potential to extend service life of denture bases in future clinical use.

Current challenges for 3D printing complete dentures: experiences from a multi-centre clinical trial.

Aims To develop an optimal clinical and laboratory protocol for the fabrication of 3D printing dentures.Design A prospective feasibility study across three UK dental schools.Material and methods Each patient received one conventional and one 3D-printed denture. Both dentures were constructed using the same impression, jaw registration and wax trial denture. Variables investigated included methods of digitisation of the impression and optional use of a 3D-printed baseplate for jaw registration.Results Clinicians strongly preferred 3D-printed baseplates. Patients felt that conventional and printed dentures were similar in retention and stability. More patients favoured conventional dentures over 3D-printed dentures in terms of comfort.Discussion It is feasible to combine conventional clinical work with digital techniques to produce 3D-printed dentures. 3D-printed baseplates offer a cost-effective alternative to conventional bases at the jaw registration stage. Challenges were faced in tooth positioning and managing occlusion, particularly where roots required adjustment.Conclusion 3D printing is suitable for producing baseplates for jaw registration blocks and wax trial insertions. It is feasible to produce 3D-printed dentures using conventional clinical techniques for impressions, jaw registration and wax trial insertion. The workflow used in this study for 3D-printed dentures is not superior to conventional dentures. Further work is required.

Ti:sapphire femtosecond laser ablation of dental enamel, dentine, and cementum.

This paper reports an investigation into the characteristics of femtosecond laser (800-nm central wavelength) in the ablation of human dental enamel, dentine, and cementum at various laser fluences from 0.2 to 3.68 J/cm(2) with single and multiple pulses. The femtosecond laser interaction with cementum is reported for the first time. Ablation thresholds were determined to be 0.58, 0.44, and 0.51 J/cm(2) for enamel, dentine, and cementum, respectively. Under the average laser fluences of 1.13 to 3.68 J/cm(2), clean ablated surfaces without debris and microcracks were obtained. Laser fluence was found to influence the ablated diameter and depth, whereas under a certain fluence, pulse number only affects the depth, without affecting the diameter. The ablation mechanism is found to be based on multi-photon absorption, not previously known for femtosecond laser ablation of dental materials. The low thermal loads of 0.708, 1.44, and 0.404 J/cm(3) required for ablating enamel, dentine, and cementum, determined for the first time, are beneficial for minimizing the heat-affected zones and micro-damage. The Raman spectroscopic analysis of phosphate shows that the chemical components of the tooth remain intact before and after the fs-laser ablation. It also shows that different dental tissues respond differently to the laser irradiation.

Assessing the physical and mechanical properties of 3D printed acrylic material for denture base application.

OBJECTIVE: Three-dimensional (3D) printing is increasingly being utilised in the dental field because of its time-saving potential and cost effectiveness. It enables dental practitioners to eliminate several fabrication steps, achieve higher precision, and attain consistency in complex prosthetic models. The properties of 3D-printed resin materials can be affected by many factors, including the printing orientation (PO) and insufficient post-curing time (CT). This study aimed to investigate the effect of PO and CT on the mechanical and physical properties of a 3D-printed denture base resin (NextDent). METHODS: 3D-printed specimens were fabricated in 0°, 45°, and 90° POs, followed by three CTs (20, 30, and 50 min). The microhardness was tested using a Vickers hardness test, while the flexural property was evaluated using a three-point bending test. Sorption and solubility were measured after the specimens had been stored in an artificial saliva for 42 days, and the degree of conversion during polymerisation was analysed using Fourier Transform Infra-red (FTIR) spectroscopy. RESULTS: The flexural strength of the material significantly increased (p < 0.05) when the printing orientation was changed from 0° to 90°. A similar increase was observed in the hardness, degree of conversion, and water sorption results. In general, no significant difference (p > 0.05) in any of the tested properties was found when the post-curing times were increased from 20 to 50 min. SIGNIFICANCE: The highest physical and mechanical properties of the 3D-printed denture base resin can be obtained by printing vertically (90° angle to the platform base). The minimal post-curing time to achieve ideal results is 30 min, as further curing will have no significant effect on the properties of the material.

The ADEPT study: a comparative study of dentists' ability to detect enamel-only proximal caries in bitewing radiographs with and without the use of AssistDent artificial intelligence software.

Introduction Reversal of enamel-only proximal caries by non-invasive treatments is important in preventive dentistry. However, detecting such caries using bitewing radiography is difficult and the subtle patterns are often missed by dental practitioners.Aims To investigate whether the ability of dentists to detect enamel-only proximal caries is enhanced by the use of AssistDent artificial intelligence (AI) software.Materials and methods In the ADEPT (AssistDent Enamel-only Proximal caries assessmenT) study, 23 dentists were randomly divided into a control arm, without AI assistance, and an experimental arm, in which AI assistance provided on-screen prompts indicating potential enamel-only proximal caries. All participants analysed a set of 24 bitewings in which an expert panel had previously identified 65 enamel-only carious lesions and 241 healthy proximal surfaces.Results The control group found 44.3% of the caries, whereas the experimental group found 75.8%. The experimental group incorrectly identified caries in 14.6% of the healthy surfaces compared to 3.7% in the control group. The increase in sensitivity of 71% and decrease in specificity of 11% are statistically significant (p <0.01).Conclusions AssistDent AI software significantly improves dentists' ability to detect enamel-only proximal caries and could be considered as a tool to support preventive dentistry in general practice.

A survey of dentists' practice in the restoration of the shortened dental arch.

OBJECTIVES: The aim of this survey was to determine how a sample of dentists working in general dental practice in the UK sought to restore the mouths of patients who had shortened dental arches (SDAs). STUDY DESIGN: A survey was conducted over a period of six months on four commercial dental laboratories. Cases of SDAs comprising the anterior teeth and 2 to 4 premolars were examined; dental prescriptions were scrutinized and a special data collection form was completed accordingly. RESULTS: A total of 140 SDA cases were examined. Most of these cases were for mandibular SDAs (88.6%). Of the recorded SDA cases, 67.2% were restored by cobalt-chromium based removable partial dentures (RPD); 25.7% were extended by acrylic-resin based RPDs; implants were provided to restore 8 SDA cases (5.7%); and only two SDA cases (1.4%) were extended by cantilevered fixed bridges. Neither the gender of the patient ([Chi (2)= 4.19, p>0.05) nor the length of the SDA ([Chi (2) = 6.51, p>0.05) influenced the choice of prosthesis to be implemented. CONCLUSIONS: It would appear from the results of this survey that among the different restorative treatment options for SDA, the RPD was the most popular treatment option for dentists surveyed in this UK study. Extending the SDA by either an implant-supported prosthesis or cantilevered fixed bridges did not appear to be a popular choice of treatment.

A systematic review of second molar distal surface caries incidence in the context of third molar absence and emergence.

Objective The aim of this systematic review was to gain a greater insight into the incidence rates of distal surface caries (DSC) on second permanent molars.Data sources A literature search using the Cochrane Library, Lilacs, Embase and Medline via Ovid retrieved English and non-English language articles from inception to June 2016. The electronic searches were supplemented with reference searching and citation tracking. Reviewers independently and in duplicate performed data extraction and completed structured quality assessments using a validated risk of bias tool for observational studies and categorised the summary scores.Data selection The search yielded 81 records and, after application of inclusion and exclusion criteria, two incidence studies were included in this systematic review.Data extraction The DSC incidence was reported in one study as relative risk (RR = 2.53; 95% CI, 1.55 to 4.14) adjacent to erupted, (RR = 0.83; 95% CI, 0.11 to 6.04) soft tissue impacted and (RR = 1.44; 95% CI, 0.55 to 3.72) bony impacted third molars in comparison to when the third molar was absent with a 25-year follow-up. The second study reported a DSC incidence of 100 surface-years (1% of all sites) with an 18-month follow-up period.Conclusions Both cohort studies indicated that DSC incidence was higher when third molars were erupted in the intermediate term, but greater over the long term for an ageing male population. However, further high-quality research is required to improve the accuracy of these findings.