AI-initiated second opinions: a framework for advanced caries treatment planning.

Integrating artificial intelligence (AI) into medical and dental applications can be challenging due to clinicians' distrust of computer predictions and the potential risks associated with erroneous outputs. We introduce the idea of using AI to trigger second opinions in cases where there is a disagreement between the clinician and the algorithm. By keeping the AI prediction hidden throughout the diagnostic process, we minimize the risks associated with distrust and erroneous predictions, relying solely on human predictions. The experiment involved 3 experienced dentists, 25 dental students, and 290 patients treated for advanced caries across 6 centers. We developed an AI model to predict pulp status following advanced caries treatment. Clinicians were asked to perform the same prediction without the assistance of the AI model. The second opinion framework was tested in a 1000-trial simulation. The average F1-score of the clinicians increased significantly from 0.586 to 0.645.

Periradicular surgery: a longitudinal registry study of ten-year outcomes and factors predictive of post-surgical extraction.

AIM: This historical prospective cohort study of the adult population of Sweden is based on data from a national registry: the primary aim was to evaluate the long-term survival of teeth after periradicular surgery. A secondary aim was to identify factors predictive of extraction within 10 years of registration of periradicular surgery. METHODOLOGY: The cohort consisted of all individuals who had undergone periradicular surgery to treat apical periodontitis, as reported to the Swedish Social Insurance Agency (SSIA) during 2009. The cohort was followed until December 31, 2020. Subsequent registrations of extractions were collected for Kaplan-Meier survival analyses and survival tables. The patients' sex, age, dental service provider and tooth group were also retrieved from SSIA. Only one tooth per individual was included in the analyses. Multivariable regression analysis was used and P < 0.05 was considered statistically significant. The reporting guidelines STROBE and PROBE were followed. RESULTS: After data cleaning, and exclusion of 157 teeth, 5 622 teeth/individuals remained for analysis. The mean age of the individuals at the time of the periradicular surgery was 60.5 years (range 20-97, standard deviation 13.31); 55% were women. At the end of the follow-up, that is, up to 12 years, a total of 34.1% of the teeth had been reported as extracted. The multivariate logistic regression analysis, based on follow-up data at 10 years after registration of the periradicular surgery, included 5 548 teeth, of which 1 461 (26.3%) had been extracted. Significant associations between the independent variables tooth group and dental care setting (both P < 0.001) and the dependent variable extraction were found. The highest odds ratio (OR) for extraction applied to tooth group: compared to maxillary incisors and canines, mandibular molars were at greatest risk of extraction (OR 2.429, confidence interval 1.975-2.987, P < 0.001). CONCLUSIONS: After periradicular surgery in predominantly elderly people in Sweden, approximately three quarters of the teeth are retained over a 10-year period. The type of tooth is associated with extraction: mandibular molars are at greater risk of extraction than maxillary incisors and canines.

The efficiency of artificial intelligence methods for finding radiographic features in different endodontic treatments - a systematic review.

OBJECTIVES: To assess the efficiency of AI methods in finding radiographic features in Endodontic treatment considerations. MATERIAL AND METHODS: This review was based on the PRISMA guidelines and QUADAS 2 tool. A systematic search was performed of the literature on cases with endodontic treatments, comparing AI algorithms (test) versus conventional image assessments (control) for finding radiographic features. The search was conducted in PubMed, Scopus, Google Scholar and the Cochrane library. Inclusion criteria were studies on the use of AI and machine learning in endodontic treatments using dental X-rays. RESULTS: The initial search retrieved 1131 papers, from which 24 were included. High heterogeneity of the materials left out a meta-analysis. The reported subcategories were periapical lesion, vertical root fractures, predicting root/canal morphology, locating minor apical foramen, tooth segmentation and endodontic retreatment prediction. Radiographic features assessed were mostly periapical lesions. The studies mostly considered the decision of 1-3 experts as the reference for training their models. Almost half of the included materials campared their trained neural network model with other methods. More than 58% of studies had some level of bias. CONCLUSIONS: AI-based models have shown effectiveness in finding radiographic features in different endodontic treatments. While the reported accuracy measurements seem promising, the papers mostly were biased methodologically.

Intra-pulpal connective tissue formation and the advanced carious lesion: Is chondrogenesis and heterotopic ossification a response to pulpal inflammation?

AIMS: (a) The aim of this study was to investigate both the formation of dense connective tissue within the dental pulp, and its association with pulpal inflammation in teeth with advanced carious lesions; and (b) to investigate in vitro whether inflammation affects the expression of markers related to chondrogenesis/osteogenesis in pulp cells. MATERIALS AND METHODS: Radiology and Histology: Forty-six teeth with advanced carious lesions were radiographically investigated for intra-pulpal radiodense structures. Specimens were processed for histology and stained with haematoxylin/eosin and proteoglycan-specific stains. The intra-pulpal connective tissue was scored as pulp stones or ectopic connective tissue. Cell culture: pulpal cells from human third molars (n = 5) were cultured in chondrogenic medium +/- TLR2/4 agonists. Expression of the genes IL6, TLR2/4, SOX9, COL1A1, COL2A1, TGFB1, RUNX2 and ALPL was assessed by qPCR. Proteoglycan content within cultures was assessed spectrophotometrically. RESULTS: Radiodense structures were discovered in about half of all pulps. They were associated with ectopic connective tissue (χ2  = 8.932, p = .004, OR = 6.80, 95% CI: [1.84, 25.19]) and with pulp stones (χ2  = 12.274, df = 1, p < .001, OR = 22.167, 95% CI: [2.57, 200.00]). The morphology of the ectopic tissue resembled cartilage and was associated with inflammatory infiltration of the pulp (χ2  = 10.148, p = .002, OR = 17.77, 95% CI: [2.05, 154.21]). After continuous stimulation of cultured cells with TLR2/4 agonists, the expression of two inflammatory markers increased: IL6 at Days 7 (p = .020) and 14 (p = .008); TLR2 at Days 7 (p = .023) and 14 (p = .009). Similarly, expression of chondrogenic markers decreased: SOX9 at Day 14 (p = .035) and TGFB1 at Day 7 (p = .004), and the osteogenic marker COL1A1 at Day 7 (p = .007). Proteoglycan content did not differ between unstimulated and stimulated cells. CONCLUSIONS: Ectopic connective tissue resembling cartilage can form in teeth affected by advanced carious lesions. This tissue type is radiographically visible and is associated with inflammatory infiltration of the pulp. Although TLR2/4 agonists led to an inflammatory response in cell culture of pulp cells, the effect on the expression of osteogenic/chondrogenic markers was limited, suggesting that immune cells are needed for connective tissue formation in vivo.

Interventions for treating cavitated or dentine carious lesions.

BACKGROUND: Traditionally, cavitated carious lesions and those extending into dentine have been treated by 'complete' removal of carious tissue, i.e. non-selective removal and conventional restoration (CR). Alternative strategies for managing cavitated or dentine carious lesions remove less or none of the carious tissue and include selective carious tissue removal (or selective excavation (SE)), stepwise carious tissue removal (SW), sealing carious lesions using sealant materials, sealing using preformed metal crowns (Hall Technique, HT), and non-restorative cavity control (NRCC). OBJECTIVES: To determine the comparative effectiveness of interventions (CR, SE, SW, sealing of carious lesions using sealant materials or preformed metal crowns (HT), or NRCC) to treat carious lesions conventionally considered to require restorations (cavitated or micro-cavitated lesions, or occlusal lesions that are clinically non-cavitated but clinically/radiographically extend into dentine) in primary or permanent teeth with vital (sensitive) pulps. SEARCH METHODS: An information specialist searched four bibliographic databases to 21 July 2020 and used additional search methods to identify published, unpublished and ongoing studies.  SELECTION CRITERIA: We included randomised clinical trials comparing different levels of carious tissue removal, as listed above, against each other, placebo, or no treatment. Participants had permanent or primary teeth (or both), and vital pulps (i.e. no irreversible pulpitis/pulp necrosis), and carious lesions conventionally considered to need a restoration (i.e. cavitated lesions, or non- or micro-cavitated lesions radiographically extending into dentine). The primary outcome was failure, a composite measure of pulp exposure, endodontic therapy, tooth extraction, and restorative complications (including resealing of sealed lesions). DATA COLLECTION AND ANALYSIS: Pairs of review authors independently screened search results, extracted data, and assessed the risk of bias in the studies and the overall certainty of the evidence using GRADE criteria. We measured treatment effects through analysing dichotomous outcomes (presence/absence of complications) and expressing them as odds ratios (OR) with 95% confidence intervals (CI). For failure in the subgroup of deep lesions, we used network meta-analysis to assess and rank the relative effectiveness of different interventions. MAIN RESULTS: We included 27 studies with 3350 participants and 4195 teeth/lesions, which were conducted in 11 countries and published between 1977 and 2020. Twenty-four studies used a parallel-group design and three were split-mouth. Two studies included adults only, 20 included children/adolescents only and five included both. Ten studies evaluated permanent teeth, 16 evaluated primary teeth and one evaluated both. Three studies treated non-cavitated lesions; 12 treated cavitated, deep lesions, and 12 treated cavitated but not deep lesions or lesions of varying depth.  Seventeen studies compared conventional treatment (CR) with a less invasive treatment: SE (8), SW (4), two HT (2), sealing with sealant materials (4) and NRCC (1). Other comparisons were: SE versus HT (2); SE versus SW (4); SE versus sealing  with sealant materials (2); sealant materials versus no sealing (2).  Follow-up times varied from no follow-up (pulp exposure during treatment) to 120 months, the most common being 12 to 24 months. All studies were at overall high risk of bias. Effect of interventions Sealing using sealants versus other interventions for non-cavitated or cavitated but not deep lesions There was insufficient evidence of a difference between sealing with sealants and CR (OR 5.00, 95% CI 0.51 to 49.27; 1 study, 41 teeth, permanent teeth, cavitated), sealing versus SE (OR 3.11, 95% CI 0.11 to 85.52; 2 studies, 82 primary teeth, cavitated) or sealing versus no treatment (OR 0.05, 95% CI 0.00 to 2.71; 2 studies, 103 permanent teeth, non-cavitated), but we assessed all as very low-certainty evidence. HT, CR, SE, NRCC for cavitated, but not deep lesions in primary teeth The odds of failure may be higher for CR than HT (OR 8.35, 95% CI 3.73 to 18.68; 2 studies, 249 teeth; low-certainty evidence) and lower for HT than NRCC (OR 0.19, 95% CI 0.05 to 0.74; 1 study, 84 teeth, very low-certainty evidence). There was insufficient evidence of a difference between SE versus HT (OR 8.94, 95% CI 0.57 to 139.67; 2 studies, 586 teeth) or CR versus NRCC (OR 1.16, 95% CI 0.50 to 2.71; 1 study, 102 teeth), both very low-certainty evidence. CR, SE, SW for deep lesions The odds of failure were higher for CR than SW in permanent teeth (OR 2.06, 95% CI 1.34 to 3.17; 3 studies, 398 teeth; moderate-certainty evidence), but not primary teeth (OR 2.43, 95% CI 0.65 to 9.12; 1 study, 63 teeth; very low-certainty evidence). The odds of failure may be higher for CR than SE in permanent teeth (OR 11.32, 95% CI 1.97 to 65.02; 2 studies, 179 teeth) and primary teeth (OR 4.43, 95% CI 1.04 to 18.77; 4 studies, 265 teeth), both very low-certainty evidence. Notably, two studies compared CR versus SE in cavitated, but not deep lesions, with insufficient evidence of a difference in outcome (OR 0.62, 95% CI 0.21 to 1.88; 204 teeth; very low-certainty evidence). The odds of failure were higher for SW than SE in permanent teeth (OR 2.25, 95% CI 1.33 to 3.82; 3 studies, 371 teeth; moderate-certainty evidence), but not primary teeth (OR 2.05, 95% CI 0.49 to 8.62; 2 studies, 126 teeth; very low-certainty evidence). For deep lesions, a network meta-analysis showed the probability of failure to be greatest for CR compared with SE, SW and HT. AUTHORS' CONCLUSIONS: Compared with CR, there were lower numbers of failures with HT and SE in the primary dentition, and with SE and SW in the permanent dentition. Most studies showed high risk of bias and limited precision of estimates due to small sample size and typically limited numbers of failures, resulting in assessments of low or very low certainty of evidence for most comparisons.

Do in vitro solubility studies on endodontic sealers demonstrate a high level of evidence? A systematic review.

OBJECTIVE: To systematically review the quality of evidence of available in vitro solubility studies on endodontic sealers according to prespecified evidence criteria. MATERIAL AND METHODS: This systematic review was based on the PRISMA guidelines and the AMSTAR measurement tool. A systematic duplicate search of the literature on endodontic sealer solubility studies was conducted in PubMed and Embase databases (until 18 October 2017). Mapping terms to subject headings and free text terms were used and combined with hand searching before exclusion of duplicates. Studies specifically dealing with endodontic sealer solubility were selected. The evidence level was graded (low, medium or high) independently by two investigators following systematic data extraction in pilot forms, which was based on prespecified evidence criteria and the modified CONSORT checklist for in vitro studies on dental materials. RESULTS: The search retrieved 1053 articles, from which 88 were assessed in full. From the 63 articles retained in the final analysis, 11 were classified as having moderate and 52 as low quality of evidence (0 high). The studies graded as low had low sample size (n < 10) and/or insufficient details to allow replicability. Most of the studies did not conform to the modified CONSORT checklist and did not include parameters considered relevant in the prespecified criteria. CONCLUSIONS: Existing in vitro studies on the solubility of endodontic sealers do not demonstrate a high quality of evidence. Most of these studies do not present systematic reporting nor employ relevant parameters prespecified in our evidence criteria.

Is pulpotomy preferable to root treatment where there is pulp exposure?

Data sources Embase, MEDLINE, Web of Science, Trip Pro, Cochrane Library, the International Clinical Trials Registry Platform and ClinicaTrials.gov, including a grey literature search.Study selection Randomised or quasi-randomised clinical trials (RCT).Data extraction and synthesis Two reviewers screened independently and extracted data separately with focus on study and population characteristics, treatment, pulp capping materials and clinical and radiographical outcome measures. Incremental cost effective ratios were collated.Results Seventeen studies reported in 21 articles were included. Three were completed trials and one ongoing trial comparing (partial/full) pulpotomy with other interventions for vital pulp therapy. The remaining 13 studies compared hydraulic calcium silicate cements with calcium hydroxide. Only three studies were considered as low risk of bias, except for performance bias (the inherent impossible task of blinding the clinician). Five trials comparing the capping materials were the basis of a quantitative synthesis. No cost-effectiveness studies were found.Conclusions Firm evidence has not been reached with respect to pulpotomy being the preferred intervention substituting root canal treatment; however better pulpotomy outcomes were reported when hydraulic calcium silicate cements are used, when compared to procedures where calcium hydroxide was used.

Ten-year follow-up on adoption of endodontic technology and clinical guidelines amongst Danish general dental practitioners.

OBJECTIVE: The aim of this study was to re-assess the adoption of certain endodontic technology and central treatment principles of root canal treatments as advocated by guidelines presented by the European Society of Endodontology. MATERIAL AND METHODS: The questionnaire included the same questions in 2003 and 2013. The general dental practitioners (GDPs) anonymously reported how frequent ('often', 'occasionally', and 'never') they used certain endodontic technology and adhered to central treatment principles. The statistical analyses were performed using Chi-squared test and Goodman-Kruskal's γ-coefficient as an association measure. RESULTS: The overall response rate of the 2013 group was 46.5% (n = 531). The frequencies of GDPs reporting often use of rubber dam, apex locator and rotary NiTi instruments were significantly higher (p < .0001) than in 2003, as well as reporting the use of composite resin for coronal sealing (p < .019). Adoption was significantly influenced by the factors gender (p = .601) and time since graduation (p = .361), and the cluster analyses revealed the neglected use of rubber dam to be associated with no established postoperative recall system. CONCLUSIONS: After 10 years, there was a higher frequency of GDPs who had adopted certain endodontic technologies. However, progress towards high-quality root canal treatment might be obstructed as the majority of GDPs avoids consistent use of rubber dam, and routinely neglects recalls for postoperative controls of their endodontic treatments.

Caries correlates strongly to salivary levels of matrix metalloproteinase-8.

The caries process in dentin involves the degradation of both mineral and organic matrix. The demineralization has been demonstrated to be caused by bacterial acids. However, the collagen degradation is considered to be initiated by endogenous proteolytic enzymes, mainly collagenolytic matrix metalloproteinases (MMPs). This paper aims to relate salivary MMP-8 (or salivary collagenase-2) and tissue inhibitor of MMP (TIMP-1) levels to manifest caries in a large number of subjects. A random sample of 451 adults (aged 18-87 years) living in the south of Sweden was included in this study. Standard clinical examinations were performed, and stimulated saliva was collected and analyzed for concentrations of MMP-8, TIMP-1 and total protein, using an immunofluorometric assay, an enzyme-linked immunosorbent assay and the Bradford assay, respectively. Salivary numbers of mutans streptococci and lactobacilli were determined using a chair-side kit. Subjects with manifest caries lesions presented with elevated levels of MMP-8 (p < 0.001) as well as total protein, MMP-8/TIMP-1 ratio, bleeding on probing and plaque index (p = 0.05) compared with subjects without manifest caries. Multiple linear regression analysis with caries as the dependent variable revealed MMP-8 as the only significant explanatory variable (p < 0.001). TIMP-1 was not significant in any case. Using MMP-8 as the dependent variable revealed total protein concentration, caries lesions (p ≤ 0.001) and salivary secretion rate (p = 0.05) as explanatory variables. In conclusion, our data reveal that subjects with manifest caries lesions have elevated levels of salivary MMP-8 relative to subjects with no caries lesions.

The antimicrobial effect of apical box versus apical cone preparation using iodine potassium iodide as root canal dressing: a pilot study.

PURPOSE: The purpose was to study the reduction of intra-canal microflora in premolars with apical periodontitis instrumented with either apical box or apical cone preparation and to provide measurements of intervention effects to allow proper power calculation in future clinical trials. METHODS: Twenty-four patients were centrally randomized to apical box preparation (size #60) or cone preparation (apical size #25). The groups were comparable regarding the presence of primary caries and type of coronal restoration. In the course of canal preparation each tooth was irrigated with 2.5% NaOCl (12 ml). Lastly, the canals were filled with 17% EDTA (2 × 30 s) and 5% iodine potassium iodide (IKI) for 10 min. The canals were sampled for micro-organisms on four occasions: before instrumentation, after instrumentation, after application of IKI dressing and at the beginning of the second appointment 1 week later. Between the treatment sessions, the root canals were sealed with IRM cement. In the laboratory, culture techniques were used to measure microbial growth, which was classified as: none, very sparse, sparse, moderate, heavy or very heavy. RESULTS: Initially, microbes were recovered in 88% of the teeth. Growth was classified as none in 35% of the teeth after instrumentation and in 50% after the application of IKI. Irrespective of the time of sampling, no significant difference in microbial growth reduction was observed between the two types of apical preparation. Based on the 1-week post-sampling, a power calculation revealed that over 900 patients are needed to show a difference of 9% between the two protocols tested. CONCLUSIONS: Future trials should be conducted using stringent protocols and as multi-centre trials for reaching the required information size.

Chapter 3: Pathological Features of Coronal Caries.

Pathology is the science of how a tissue changes during the process of the disease. The pathology is of important knowledge for understanding subsequent treatment concepts of a disease. In the cariology field, pathological features of caries are often presented using tooth sections, whereby the sequence and spread can be monitored. It is optimal to describe such changes using thin undecalcified tooth sections as an overview can be given of both enamel demineralization and pulp-dentine reactions. Also, an optimal understanding is achieved if the clinical status of carious lesion activity is known. Different studies using human teeth have shown the principle changes in progressive stages of carious lesions; the growth of the enamel lesion reflects the growth condition of the cariogenic biofilm. Surprisingly, the pulp (the odontoblast) is aware of the cariogenic stimuli even before mineral alteration has taken place within the dentine. The microorganisms mainly invade the dentine during enamel cavitation. In this chapter, the current improvement of knowledge on advanced carious lesions has been assessed in detail both histologically and radiographically. From a radiographic point of view, well-defined deep and extremely deep carious lesions and their difference are presented. Recent advances in artificial intelligence (AI) in medicine have raised the possibility of increasing the accuracy and speed of histopathological examination techniques. However, the literature involving AI-based histopathological features of hard and soft dentinal tissue pathologic changes is still scarce.

Dimensional changes of endodontic sealers-An in vitro model simulating a clinical extrusion scenario during 18 months.

OBJECTIVES: To examine the dimensional changes of endodontic sealers during 18 months using three-dimensional (3D) surface scanning and subtraction radiography in a novel in vitro sealer-extrusion model. MATERIAL AND METHODS: Fifty endodontically instrumented acrylic teeth were randomly allocated to five groups (n = 10) filled with Apexit Plus, AH Plus, BioRoot RCS, TubliSeal EWT, and gutta-percha (control). Freshly mixed sealers were intentionally extruded during obturation. All teeth were immersed in a physiologic solution for up to 18 months. Blinded 3D surface scans (resolution: ~10 µm) and digital radiographs of the teeth were obtained at baseline (immediately after obturation); and then after 1 week, and at 1, 3, and 18 months. For blinded assessment of sealer dimensional change, 3D models and radiographs were superimposed using specific software. Volumetric differences, root mean square (RMS), and area change from subtraction radiography measured at each period within each sealer group were thereafter calculated. Repeated measures analyses were done with Bonferroni adjustment for multiple comparisons; standard errors, p values, and 95% confidence intervals (CI) were reported. RESULTS: Analyses of the volumetric data confirmed significant, progressive material loss for Apexit Plus when compared to the other investigated sealers or the control group (p ≤ 0.02). Immersion period significantly influenced the volumetric dimensional changes of Apexit Plus already after 1 month (p < 0.01). For TubliSeal EW, the effect of the immersion period on the dimensional changes was noted after immersion for 3 months (p ≤ 0.02), while for BioRoot RCS this was evident only at 18 months (p < 0.01). Same trends were noted for the RMS data, whereas progressive dimensional changes using subtraction radiography only revealed significant changes for Apexit Plus (p = 0.01). CONCLUSIONS: The largest dimensional changes were shown by Apexit Plus, followed by Tubliseal EWT and BioRoot RCS. AH Plus remained stable throughout 18 months.

Prediction of pulp exposure before caries excavation using artificial intelligence: Deep learning-based image data versus standard dental radiographs.

OBJECTIVES: The objective was to examine the effect of giving Artificial Intelligence (AI)-based radiographic information versus standard radiographic and clinical information to dental students on their pulp exposure prediction ability. METHODS: 292 preoperative bitewing radiographs from patients previously treated were used. A multi-path neural network was implemented. The first path was a convolutional neural network (CNN) based on ResNet-50 architecture. The second path was a neural network trained on the distance between the pulp and lesion extracted from X-ray segmentations. Both paths merged and were followed by fully connected layers that predicted the probability of pulp exposure. A trial concerning the prediction of pulp exposure based on radiographic input and information on age and pain was conducted, involving 25 dental students. The data displayed was divided into 4 groups (G): GX-ray, GX-ray+clinical data, GX-ray+AI, GX-ray+clinical data+AI. RESULTS: The results showed that AI surpassed the performance of students in all groups with an F1-score of 0.71 (P < 0.001). The students' F1-score in GX-ray+AI and GX-ray+clinical data+AI with model prediction (0.61 and 0.61 respectively) was slightly higher than the F1-score in GX-ray and GX-ray+clinical data (0.58 and 0.59 respectively) with a borderline statistical significance of P = 0.054. CONCLUSIONS: Although the AI model had much better performance than all groups, the participants when given AI prediction, benefited only 'slightly'. AI technology seems promising, but more explainable AI predictions along with a 'learning curve' are warranted.

Three-dimensional analysis of the pulp cavity on surface models of molar teeth, using X-ray micro-computed tomography.

AIM: The purpose of this study was to investigate the scanning and segmentation precision of surface models of molars for the detection of small volumes, such as the reduced pulp cavity; formation of mineral deposits; detection of narrow root canals and to improve the clinical and morphological understanding of the number of root canals and their configuration. METHODS: Eighteen human molars were scanned using X-ray micro-computed tomography. The reconstruction of the surface models had a precision of <1 voxel, using three-dimensional software and quantitative color mapping. In order to relate the measurements to changes over time the size of the pulp chambers was classified in two well-defined groups. RESULTS: The mineral deposits were more evenly distributed in small pulp chambers than in large, but complete root canal calcification was never observed. No difference was observed in the material with respect to the presence of intra-radicular connections. In upper molars, a second mesiobuccal canal (mb(2)) frequency of 91% was found. The difference in length between the first mesiobuccal canal (mb(1)) and mb(2) was <1 mm. The number of root canals could be related to the number of root cones. CONCLUSION: In summary, three-dimensional surface models were made with a high precision; an increased accumulation of mineral deposits was noted in molars with small pulp chambers and combined with the consistent pattern of intra-radicular connections, the potential endodontic treatment complexity is underlined in such cases. Finally, an improved understanding of root canal prevalence was reached, when merging well-defined definitions on root morphology and clinical classification systems.

In deep cavities stepwise excavation of caries can preserve the pulp.

DATA SOURCES: Medline and the Igaku Chuo Zasshi (Japanese) databases, the reference list of identified studies and personal reprint collections of authors were searched. STUDY SELECTION: Randomised controlled trials (RCT), controlled clinical trials (CCT) and case series conducted in permanent teeth were included. DATA EXTRACTION AND SYNTHESIS: Two independent reviewers extracted the data using specially designed forms. A qualitative synthesis is presented. RESULTS: Ten English and three Japanese studies were finally included (two RCTs, five CCTs and six case series). CONCLUSIONS: From this review, stepwise excavation can be concluded as effective for pulp preservation in extremely deep caries where there are no clinical symptoms of irreversible pulpitis. Calcium hydroxide and other materials, such as antimicrobials and polycarboxylate cement combined with tannin fluoride preparation, have been shown to be effective in reducing bacteria after stepwise excavation. Further clinical trials with high levels of study design in this research field are needed to identify the best possible methods for removing carious dentine during stepwise excavation.

Stepwise excavation may enhance pulp preservation in permanent teeth affected by dental caries.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Ways of enhancing pulp preservation by stepwise excavation-a systematic review. Hayashi M, Fujitani M, Yamaki C, Momoi Y. J Dent 2011;39(2):95-107. Epub 2010 Dec 3. REVIEWER: Lars Bjørndal, DDS, PhD, Dr Odont PURPOSE/QUESTION: To determine the clinical effectiveness of stepwise excavation for pulp preservation SOURCE OF FUNDING: Japanese Society of Conservative Dentistry TYPE OF STUDY/DESIGN: Systematic review LEVEL OF EVIENCE: Level 2: Limited-quality patient-oriented evidence STRENGTH OF RECOMMENDATION GRADE: Grade B: Limited-quality patient-oriented evidence.

Endodontic management of pulp canal obliteration using a new single-tooth template: A case series.

Background: Guided Endodontics is suggested as a reliable method for management of teeth with pulp canal obliteration (PCO). The guide used for this usually involves multiple teeth to gain stability but is bulky. It is therefore suboptimal to be used along with rubber dam. Aim: To describe the use of a minimized single-tooth guide template in three patients with radiographic evidence of PCO. Design: The template was designed and fabricated using the cone-beam computed tomography (CBCT) scan and a surface scan image of the involved teeth. In all three patients, the root canals were successfully negotiated within 15 minutes, with the template involving only the tooth in focus or with neighboring half of the teeth. The operator stabilized the template if required. Conclusions: This case series shows clinically that successful outcome can be obtained during guided endodontics with the use of a single-tooth template in previously traumatized anterior teeth with PCO.

Treatment of deep caries lesions in adults: randomized clinical trials comparing stepwise vs. direct complete excavation, and direct pulp capping vs. partial pulpotomy.

Less invasive excavation methods have been suggested for deep caries lesions. We tested the effects of stepwise vs. direct complete excavation, 1 yr after the procedure had been carried out, in 314 adults (from six centres) who had received treatment of a tooth with deep caries. The teeth had caries lesions involving 75% or more of the dentin and were centrally randomized to stepwise or direct complete excavation. Stepwise excavation resulted in fewer pulp exposures compared with direct complete excavation [difference: 11.4%, 95% confidence interval (CI) (1.2; 21.3)]. At 1 yr of follow-up, there was a statistically significantly higher success rate with stepwise excavation, with success being defined as an unexposed pulp with sustained pulp vitality without apical radiolucency [difference: 11.7%, 95% CI (0.5; 22.5)]. In a subsequent nested trial, 58 patients with exposed pulps were randomized to direct capping or partial pulpotomy. We found no significant difference in pulp vitality without apical radiolucency between the two capping procedures after more than 1 yr [31.8% and 34.5%; difference: 2.7%, 95% CI (-22.7; 26.6)]. In conclusion, stepwise excavation decreases the risk of pulp exposure compared with direct complete excavation. In view of the poor prognosis of vital pulp treatment, a stepwise excavation approach for managing deep caries lesions is recommended.

Guided Endodontics Modified for Treating Molars by Using an Intracoronal Guide Technique.

The aim of this case report was to show the concept of guided endodontics in a maxillary first molar with limited interocclusal space. Guided endodontics involves merging cone-beam computed tomographic imaging and a surface scan of the tooth in order to create a guide to perform a drill path into the seemingly obliterated root canal. In the molar region, the interocclusal space is often too small to accommodate the guide, bur, and handpiece at once, and, therefore, a modified approach is presented. A 52-year-old man was referred because the dentist had failed to localize the distobuccal root canal of a maxillary molar (#3) associated with apical pathosis. After reopening and rubber dam placement, a glide path was established for both the palatal first mesiobuccal root canal and the second mesiobuccal using a size 10 hand file and coronal flaring. Further instrumentation to the working length was achieved by reciprocating file size 25. All 3 canals were temporarily filled with calcium hydroxide. For the distobuccal root canal, guided endodontics was chosen in order to avoid further impairment of the tooth because negotiation of the canal failed even with the use of the operating microscope. Following the merged data obtained from the cone-beam computed tomographic and surface scans, a translucent SICAT Optiguide (SICAT, Bonn, Germany) was constructed containing a sleeve representing the proper direction of a drill path in order to reach the distobuccal root canal. The access cavity was temporarily filled with a composite material made for light-curing. Before light curing, the Optiguide was replaced on the teeth, and a steel pin was pressed through the sleeve and the composite whereby the proper drill path direction was transferred into the composite. After polymerization and removal of the Optiguide and pin from the composite base sleeve, the guided drilling could be performed. This case report is the first on guided access preparation in a molar with pulp canal obliteration and limited interocclusal space. The demand for more interocclusal space was solved by transforming the virtual drill path into a composite-based intracoronal guide. The use of digital technology was essential.