Enamel caries lesions, with and without initial cavitation, in relation to anatomical areas of the proximal surface in deciduous molars.

Objective: proximal enamel caries lesions (PEC) are believed to initiate and progress to cavitation below the proximal contact area (PCA), but no evidence exists on the location of initial carious cavitation on the proximal surface with functional PCA. This study aimed to test the association of anatomical areas of the proximal surface with the severity of PEC and the frequency of cavitation in PEC in primary molars DESIGN: laboratory, observational, transversal study. Exfoliated primary molars (n = 33) with functional PCA (biofilm-free PCA surrounded by biofilm) had their proximal surfaces (one/tooth) divided anatomically into up to nine areas: 3 areas based on the occlusal/cervical PCA boundaries (areas I, II, and III; occluso-cervically) and 3 areas based on the bucco/lingual PCA boundaries (A, B, and C), with area IIB representing the PCA and area IIIB as the sub-PCA (below the PCA).

Influence of carbonated acid beverage on fracture resistance and marginal gap formation in different restorative approaches to non-carious cervical lesions.

Objective: This study is to evaluate fracture resistance, failure mode, and gap formation at the restorative interface of unrestored or restored non-carious cervical lesions (NCCLs) submitted to a short-term erosive environment.

Materials And Methods: Artificial NCCLs were produced in vitro in bovine incisors, and were randomly divided into four restorative resins groups (n = 22): nanohybrid-NR; bulk-fill-BR; flow with a nanohybrid layer-FNR; bulk-fill with a nanohybrid layer-BNR; and a group unrestored-UR (n = 16). Half of the specimens were submitted to an erosive challenge (per 5 min, 3 × a day for 7 days, before and after restoration), and the other half, was immersed in artificial saliva.

Organic volume and permeability variations in the surface layer of artificial and natural enamel carious lesions.

Objectives: Test the hypothesis the type of enamel caries (natural, artificial induced by gel, and artificial induced by acid solutions) affect the organic volume and the permeability of the surface layer in enamel caries lesions.

Design: Artificial enamel caries, induced by either acidic solution (organic-poor; Group 1) or acidic gel (organic-rich; Group 2), and natural non-cavitated inactive approximal enamel caries lesions (NEC; Group 3) were obtained, from which longitudinal ground sections were prepared. Measurements of the mineral (V) (by microradiography), and water (α) and organic (β) volumes (by optical birefringence) were obtained at three points in the surface layer (n = 30/group).

Improved mineralization of dental enamel by electrokinetic delivery of F and Ca ions.

This in vitro study evaluated the effects of the infiltration of F and Ca ions into human enamel by electrokinetic flow (EKF) on the enamel microhardness and F content. Sound human enamel ground sections of unerupted third molars were infiltrated with de-ionized water by EKF and with F ion by EKF respectively. All samples were submitted to two successive transverse acid-etch biopsies (etching times of 30 s and 20 min) to quantify F ion infiltrated deep into enamel.

New Theory Illustrates the Formation of Enamel CUP-Shaped Lesions on Occlusal Surfaces.

We propose a new theory for enamel cupping lesions formation. At early stages, naturally formed cupping lesions showed increased porosity at two structural prismatic traits: the central cone extending into the enamel-dentine junction and the type-I Hunther-Schreger bands (HSB), suggesting them to be the main drivers for cupping lesion formation and development. In addition, these lesions were circumscribed by type-II HSBs, which present lower surface porosity and higher resistance to wear.

Structure and Chemical Composition of ca. 10-Million-Year-Old (Late Miocene of Western Amazon) and Present-Day Teeth of Related Species.

Molecular information has been gathered from fossilized dental enamel, the best-preserved tissue of vertebrates. However, the association of morphological features with the possible mineral and organic information of this tissue is still poorly understood in the context of the emerging area of paleoproteomics. This study aims to compare the morphological features and chemical composition of dental enamel of extinct and extant terrestrial vertebrates of Crocodylia: Purussaurus sp.

Orofacial antinociceptive effects of perillyl alcohol associated with codeine and its possible modes of action.

This study evaluated the orofacial antinociceptive effect of (S)-(-)-perillyl alcohol (PA) associated with codeine (C) and investigated the possible molecular anchorage mechanisms of PA. Mice (n = 5 per group) were treated with PA alone and associated with codeine and assigned to the following groups: 75.0 mg/kg PA; 75.

Comparative Analysis of Continuous versus Reciprocating Instruments in Retreatment of Flat-oval Root Canals.

Introduction: Flat-oval root canals of incisors can be problematic in retreatments. This study assessed the efficacy of continuous and reciprocating rotation instruments in retreatment of flat-oval root canals in lower incisors via micro-computed tomography (micro-CT). File systems studied were ProTaper universal retreatment rotary system associated with ProTaper Next (PTUR+PTN), D-RaCe associated with iRaCe (DR+iR), Reciproc (REC), and WaveOne (WO).

Shaping efficiency of XP-endo shaper and Mtwo instruments in long oval root canals: A micro-CT study.

This study evaluated the shaping ability of XP-endo Shaper and Mtwo systems in long-oval-shaped canals of extracted human mandibular molars using micro-computed tomography (micro-CT). Images recorded before and after preparation were evaluated for morphometric measures regarding increase in canal volume, dentin removed, surface area, untouched walls and structure model index (SMI). Data were statistically analysed using the Mann-Whitney test with 5% of significance.

The effect of high concentration of zoledronic acid on tooth induced movement and its repercussion on root, periodontal ligament and alveolar bone tissues in rats.

Zoledronic acid (ZA) is often prescribed for osteoporosis or resorptive metabolic bone disease. This study aims to evaluate the effect of ZA on orthodontic tooth movement (OTM) and root and bone resorption and its repercussion on root, periodontal ligament and alveolar bone tissues. The experimental group consisted of 72 Wistar rats divided in four subgroups: Naive, Saline and Zoledronic Acid groups at the concentration of 0.

Susceptibility of Dental Enamel of Different Ages to Caries-Like Lesion Development.

This study investigated the impact of estimated age, anatomical location, and the presence of wear facets on the susceptibility of enamel to develop caries-like lesions. Extracted human premolars (n = 261) had their age estimated between 10 and 93 years old, using established forensic methods. Specimens of enamel (4 × 4 mm) were prepared from the middle of the buccal surfaces, preserving the outer surface layer.

Variation in mineral, organic, and water volumes at the neonatal line and in pre- and postnatal enamel.

Objetives: The neonatal line (NNL) in enamel is hypomineralized, but quantitative data on the enamel component volumes of the NNL are lacking. This study aimed at quantifying the variation in the mineral, organic, and water volumes at the NNL and in pre- and postnatal enamel.

Materials And Methods: In buccal enamel longitudinal ground sections of exfoliated primary incisors (upper and lower; n = 17), the enamel component volumes were quantified at five histological sites (located at 40 μm intervals along a transversal line): the NNL, two sites in prenatal enamel, and two sites in postnatal enamel.

Morphologic Changes of Apical Foramen and Microcrack Formation after Foraminal Enlargement: A Scanning Electron Microscopic and Micro-computed Tomographic Analysis.

Introduction: The aim of the present study was to evaluate the morphologic changes on the apical foramen and the formation of dentinal microcracks after foraminal enlargement in straight and curved root canals using scanning electron microscopic (SEM) and micro-computed tomographic (micro-CT) analyses.

Methods: Sixty teeth were selected and divided into 2 experimental groups: GI (incisors/straight group, n = 30) and GM (molars/curved group, n = 30). Each group was divided into 2 subgroups (n = 15) according to the analysis performed: SEM or micro-CT analysis.

Microtomographic analysis of the effect of sodium alendronate on orthodontic movement in rats.

Objective: To evaluate the effect of sodium alendronate on orthodontic tooth movement in rats using microtomographic analysis.

Settings And Sample Population: Thirty male Wistar rats (Rattus norvegicus) were divided into three groups of 10 rats and administered saline (control), 1 mg/kg sodium alendronate or 6 mg/kg sodium alendronate, respectively.

Materials And Methods: The drug was administered once per week for 5 weeks by gavage.

Influence of infiltrant application time on the reduction of opaqueness of proximal enamel caries.

Introduction: Infiltrant resins were developed to hamper carious lesion progression and mask the whitish appearance of first evidence of caries.

Objective: This study aimed at testing the hypothesis that a long application time of resin infiltrant in proximal enamel caries improves esthetic outcome compared to the commercially recommended time.

Materials And Methods: Twenty teeth with uncavitated inactive proximal white enamel caries lesions (selected by two calibrated examiners; inter-examiner κ = 0.

Natural enamel caries, dentine reactions, dentinal fluid and biofilm.

It is believed that penetration of dentinal fluid into natural enamel caries (NEC) is negligible because of the barrier created by underlying sclerotic dentine, but there are conflicting evidences on whether dentine subjacent to NEC is sclerotic or demineralized. This study aimed at investigating the relationship between NEC, subjacent dentine reactions, modification of dentinal fluid, and composition of cariogenic biofilm formed on the NEC surface. Proximal NEC (PNEC) lesions of human permanent posterior teeth were included in five experiments.

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge.

The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Brackets were bonded to bovine incisors.

High Amount of Organic Matter during Caries Formation Reduces Remineralization and Resin Infiltration of Enamel Caries.

The amount of organic material in the cariogenic environment correlates with the amount of organic material incorporated in carious enamel. The incorporated organic material may be expected to reduce the pore volumes available for remineralization and resin infiltration, but these expected outcomes have not yet been quantified. We tested the effect of the amount of organic content in the cariogenic agent on remineralization and the resin-occluded pore volume in artificial subsurface enamel caries.

Correction: Correlation between ICDAS and histology: Differences between stereomicroscopy and microradiography with contrast solution as histological techniques.

[This corrects the article DOI: 10.1371/journal.pone.

Natural enamel caries in quinoline: Volumetric data and the pattern of infiltration.

This study aimed to test the hypotheses that (i) a parameter related to permeability, α (ratio of squared water volume by the nonmineral volume) is, among all major component volumes (mineral, water, and organic volumes) the best predictor of quinoline infiltration in natural enamel caries (NEC), and (ii) the pore volume fraction infiltrated by quinoline (V ) in NEC is much lower than previous estimates that neglected water and organic enamel volumes. Mineral and nonmineral volumes and α were measured at 341 histological points (from 20 approximal NEC lesions), and transport of quinoline was tracked by orientation-independent polarizing microscopy. R values of V were 0.

Correlation between ICDAS and histology: Differences between stereomicroscopy and microradiography with contrast solution as histological techniques.

Detection of occlusal caries with visual examination using ICDAS correlates strongly with histology under stereomicroscopy (SM), but dentin aspects under SM are ambiguous regarding mineral content. Thus, our aim was to test two null hypotheses: SM and microradiography result in similar correlations between ICDAS and histology; SM and microradiography result in similar positive (PPV) and negative predictive values (NPV) of ICDAS cut-off 1-2 (scores 0-2 as sound) with histological threshold D3 (demineralization in the inner third of dentin). Occlusal surfaces of extracted permanent teeth (n = 115) were scored using ICDAS.

Quantitative study of the proportion of the pore volume of human fluorotic enamel filled by resin infiltrant.

Aim: Capillarity theory predicts that the pore volume infiltrated by a liquid in a body with tubular capillaries is directly proportional to the capillary radius. The expected volume available for infiltration is the loosely bound water volume, which can be related to the capillary radii. We tested the hypothesis that the proportion of the pore volume infiltrated by resin infiltrant (V) is correlated and agrees with the proportion of the pore volume with loosely bound water ( [Formula: see text] ).

Is the morphology and activity of the occlusal carious lesion related to the lesion progression stage?

Objective: To investigate the relationship between degree of dentin demineralization with both lesion activity and morphology of the occlusal carious cavity.

Design: Occlusal sites (n=138) were identified by visual examination (Nyvad's scores 0-6) in 67 extracted teeth which were scanned in a high energy micro-CT. After 3D reconstruction, each stack was resliced in the mesio-distal direction and tooth mineral density (MD) was measured along a path from enamel to the deepest part of dentin in the slice showing the most severe carious involvement.