The suitability of panoramic radiographs for clinical decision making regarding root angulation compared to cone-beam computed tomography.

BACKGROUND: The study compared clinical decisions regarding root angulation correction and root proximity based on the interpretation of Panoramic (PAN) versus Cone-Beam Computed Tomography (CBCT) images. METHODS: A total of 864 teeth from 36 existing, radiographic patient records at a university dental clinic with concurrent PAN and CBCT images were assessed using PANs, then using CBCTs in a blinded manner by two orthodontists. Teeth were rated regarding the need for root repositioning, the direction of repositioning and existence of root proximity. Frequencies, rating time and intra- and inter-examiner Cohen's Kappa were calculated. RESULTS: There was 73.7-84.5% agreement between PAN-based and CBCT-based orthodontists' decisions regarding the need to reposition roots. Root proximity was more frequently reported on PANs than CBCTs by one examiner (p = 0.001 and p = 0.168). Both PANs and CBCTs had moderate to substantial intra-examiner, within-radiograph-type reliability with Kappa values of 0.686-0.79 for PANs, and 0.661 for CBCTs (p < 0.001). Inter-examiner and inter-radiograph-type Kappa values ranged from 0.414 to 0.51 (p < 0.001). Using CBCT decisions as a reference, 78.9% of PAN decisions were coincident, 9.3% would have been repositioned on CBCT but not on PAN, 11.3% would not have been repositioned on CBCT but were on PAN, and 0.3% would have been repositioned in the opposite direction on CBCT versus PAN. Additionally, CBCT images required more time per tooth to assess than PANs (p < 0.001). CONCLUSIONS: PAN-based clinical decisions regarding root angulation had comparable statistical reliability and substantial agreement with CBCT-based clinical decisions.

Microcomputed Tomography Calibration Using Polymers and Minerals for Enamel Mineral Content Quantitation.

OBJECTIVE: The aim of this paper was to develop calibration standards (CSs) that are readily available for clinical researchers for the quantitation of enamel mineral content. METHOD: Polyethylene terephthalate (PET), acetal, polyphenylene sulfide (PPS), selenite, Egyptian alabaster, aragonite, and fluorite were fashioned into discs, and their densities were measured and stacked for microcomputed tomography examination. Frame averaging, flat-field correction, pre-filtration, and beam-hardening correction were applied. CSs were checked for homogeneity. The linear relationship between the mean greyscale value (GSV) of each disc and its physically calculated density was explored, and reproducibility was tested. A calibration function was established and then validated using a bovine enamel disc and sound enamel of extracted human premolar teeth. RESULTS: Measured densities were PET (ρ = 1.38 g/cm3), acetal (ρ = 1.41 g/cm3), PPS (ρ = 1.64 g/cm3), selenite (ρ = 2.24 g/cm3), Egyptian alabaster (ρ = 2.7 g/cm3), aragonite (ρ = 2.72 g/cm3), and fluorite (ρ = 3.11 g/cm3). Examination of the profile sections of CSs confirmed the uniformity of GSVs with minimal beam-hardening effect. A squared Pearson correlation coefficient of R2 = 0.994 was determined between the mean GSV of each CS and its calculated density and was reproduced at different settings with R2 >0.99. A linear regression equation of density (y) versus GSV (x) was established using the least squares regression equation method. The estimated density of the bovine enamel disc (2.48 g/cm3) showed high accuracy when compared to the physically measured value (2.45 g/cm3). The -relative error was 1.2%. Densities of sound enamel in the extracted human premolar teeth were 2.6-3.1 g/cm3. CONCLUSIONS: This is a simple, valid, and reproducible method to quantitate enamel mineral content. This simple, yet accurate system could be used to expand knowledge in the field of enamel caries research.

Three-dimensional characterization of naturally developed early caries lesions using high-resolution micro-computed tomography.

OBJECTIVES: The goal of this micro-Computed-Tomography (µCT) study was to characterize the structural parameters of natural, early proximal enamel caries lesions and correlate them with two-dimensional radiographic findings. METHODS: Extracted human premolar teeth with ICDAS score 2 proximal lesions were examined using visual-tactile, µCT and simulated bitewing radiographs (BTX). Sound enamel and caries-lesions' structural and mineral density (MD) parameters were analyzed which included surface layer (SL) status and thickness, depth of lesion, and MD. RESULTS: Thirty-six extracted premolars with 54 proximal early enamel caries lesions were analyzed. Lesions varied notably in lesion depth and MD. SL thickness ranged between 20 and 139µm. Three teeth (5.6%) had micro-cavitations upon the µCT examination despite being "clinically" non-cavitated. Cavitation status had no significant association with µCT nor BTX radiographic depth. Depth of lesions correlated weakly but statistically significantly with mineral loss (ML) at body of lesion (r=0.301, p=0.027). SL thickness also correlated negatively with ML at SL (r=-0.501, p<0.001). CONCLUSIONS: Early proximal enamel lesions with ICDAS 2 score as determined by visual-tactile examination exhibited a wide range of lesion parameters and cavitation status when examined by µCT. Visual-tactile examination may fail to detect micro-cavitations in enamel surface that are detectable by µCT. CLINICAL SIGNIFICANCE: Clinicians have direct access to early proximal enamel lesions during orthodontic separation, exfoliation, extraction or restoration of adjacent teeth. This study invites the clinician to consider more decisive management options in high risk individuals (e.g. micro-invasive techniques), given the finding of vast structural variability of such lesions.

Efficacy of Chewing Gum to Reduce Orthodontic Pain Compared to Placebo: A Blinded, Parallel-Group, Preliminary Clinical Trial.

AIMS: To quantify the pain experienced by orthodontic patients during the first 10 days of appliance placement, to determine whether chewing gum reduces orthodontic pain compared to placebo, and to examine patients' overall perceptions of the impact of orthodontic pain. METHODS: Patients bonded with fixed appliances were randomly assigned to one of two groups (gum group [GG] or placebo group [PG]) and then followed for 10 days. The main outcome was a visual analog scale (VAS) pain score, and the secondary outcomes included patients' subjective assessments of overall pain level, the impact of pain on hygiene habits and treatment decision, and the frequency of analgesics consumption. Eighty kits (40 for GG and 40 for PG) were pre-randomized and concealed before patient enrollment using a computer-generated random sequence. Operators and patients were blinded. Data were analyzed using generalized linear models and Mann-Whitney U, chi-square, and Fisher exact tests. RESULTS: A total of 75 patients were allocated to intervention groups; 37 participated and completed diaries (20 in GG and 17 in PG). No statistically significant differences were detected between the GG and PG groups in any tested variable. Pain negatively affected some patients' oral hygiene practices. A mismatch existed between patient expectations and actual pain experiences. Female patients used analgesics more frequently than male patients (P = .046). CONCLUSION: Chewing gum three times per day does not seem to significantly reduce orthodontic pain compared to placebo. Orthodontists should manage their patients' pain expectations.

Does the Removal of Cementum Facilitate Bacterial Penetration into Dentinal Tubules In Vitro?

INTRODUCTION: The importance of an intact layer of cementum on the root surface in preventing bacterial penetration into radicular dentin has not been sufficiently investigated. The aim of this in vitro study was to determine the effect of the absence of cementum from the root surface and the length of the infection period (2 or 4 weeks) on the maximum depth of bacterial penetration and the percentage of sectors lined with bacteria. METHODS: Sound, single-rooted extracted teeth with closed apices were randomly assigned to either a control group (cementum present [CP]) or an experimental group (cementum removed [CR]). Each group was further divided randomly into 2 subgroups: 2-week infection (CP2 and CR2) and 4-week infection (CP4 and CR4). Teeth were then artificially infected with Enterococcus faecalis and prepared for histology. RESULTS: A total of 107 teeth were available for histologic examination, 25 teeth in CP2, 31 teeth in CP4, 27 teeth in CR2, and 24 teeth in CR4. Pairwise comparisons revealed statistically significant differences in the maximum depth of bacterial penetration for the following combinations: CP2-CR2, CP2-CR4, CP4-CR2, and CP4-CR4 (P < .001). Pairwise comparisons also revealed a statistically significant difference in the percentage of sectors lined with bacteria for CP2-CR2, CP2-CP4, and CP2-CR4 (P < .001). CONCLUSIONS: The results support the hypothesis that the absence of cementum facilitates bacterial penetration into dentinal tubules. Results also suggest that the process of radicular dentin infection is time dependent and highlight the importance of early treatment of infected teeth, especially in situations in which cementum discontinuity is suspected.

The effect of clove and benzocaine versus placebo as topical anesthetics.

OBJECTIVES: The purpose of this study was to examine whether the natural herb clove can replace benzocaine as a topical anesthetic. METHODS: Topical agents were applied to the maxillary canine buccal mucosa of 73 adult volunteers. Four substances were tested in the study: (1) homemade clove gel, (2) benzocaine 20% gel, (3) placebo that resembles clove and (4) a placebo that resembled benzocaine. After 5 min of material application in a randomized, subject-blinded manner, each participant received two needle sticks. Pain response was registered using a 100 mm visual analogue pain scale. RESULTS: Both clove and benzocaine gels had significantly lower mean pain scores than placebos (p=0.005). No significant difference was observed between clove and benzocaine regarding pain scores. CONCLUSION: Clove gel might possess a potential to replace benzocaine as a topical agent before needle insertion.