Effects of experimental in-office bleaching gels incorporated with co-doped titanium dioxide nanoparticles on dental enamel physical properties.

To evaluate the physical properties of enamel submitted to hydrogen peroxide (HP) incorporated with titanium dioxide nanoparticles (NP) co-doped with nitrogen and fluorine and irradiated with violet LED light (LT). Enamel-dentin disks were randomly allocated (T0) into groups, according to HP (HP6, HP15, or HP35) and NP (no NP, 5NP, or 10NP) concentrations, and irradiated or not with LT. A negative control (NC) group was set. After three bleaching sessions (T1, T2, and T3), specimens were stored in saliva for 14 days (T4). Enamel surface microhardness number (KHN), surface roughness (Ra), cross-sectional microhardness (ΔS), energy-dispersive spectroscopy (EDS), scanning electron (SEM), and polarized light (PLM) microscopies were performed. Surface KHN was significantly influenced by NP over time, independently of LT irradiation. At T3 and T4, gels with 5NP and 10NP exhibited no KHN differences compared to NC and baseline values, which were not observed under the absence of NP. NP incorporation did not statistically interfere with the ΔS and Ra. PLM images exhibited surface/subsurface darkening areas suggestive of demineralizing regions. SEM demonstrated some intraprismatic affection in the groups without NP. EDS reported a higher enamel calcium to phosphorus ratio following 10NP gels applications. Gels with NP maintained the enamel surface microhardness levels and seemed to control surface morphology, upholding the mineral content. None of the proposed experimental protocols have negatively influenced the enamel surface roughness and the cross-sectional microhardness.

Optimization of a Validated Protocol That Determines Bioavailable Fluoride in Toothpastes.

A validated protocol used to determine how much of total fluoride is bioavailable in toothpaste formulations was evaluated if it could be simplified regarding the following parameters: (1) concentration of the slurry (0.25-4%), (2) centrifugation speed (1,000-12,000 g) and time (1-10 min), and (3) incubation time for FPO32- ion hydrolysis and insoluble-F dissolution (15-60 min). Fresh and aged Na2FPO3/CaCO3 and fresh NaF/SiO2-based toothpastes were analyzed (n = 9). The improvements were the centrifugation at 1,000 g for 5 min is enough to separate insoluble-F and the time for FPO32- ion hydrolysis and insoluble-F dissolution can be shortened to 30 min.

Three-dimensional maxillary virtual patient creation by convolutional neural network-based segmentation on cone-beam computed tomography images.

OBJECTIVE: To qualitatively and quantitatively assess integrated segmentation of three convolutional neural network (CNN) models for the creation of a maxillary virtual patient (MVP) from cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: A dataset of 40 CBCT scans acquired with different scanning parameters was selected. Three previously validated individual CNN models were integrated to achieve a combined segmentation of maxillary complex, maxillary sinuses, and upper dentition. Two experts performed a qualitative assessment, scoring-integrated segmentations from 0 to 10 based on the number of required refinements. Furthermore, experts executed refinements, allowing performance comparison between integrated automated segmentation (AS) and refined segmentation (RS) models. Inter-observer consistency of the refinements and the time needed to create a full-resolution automatic segmentation were calculated. RESULTS: From the dataset, 85% scored 7-10, and 15% were within 3-6. The average time required for automated segmentation was 1.7 min. Performance metrics indicated an excellent overlap between automatic and refined segmentation with a dice similarity coefficient (DSC) of 99.3%. High inter-observer consistency of refinements was observed, with a 95% Hausdorff distance (HD) of 0.045 mm. CONCLUSION: The integrated CNN models proved to be fast, accurate, and consistent along with a strong interobserver consistency in creating the MVP. CLINICAL RELEVANCE: The automated segmentation of these structures simultaneously could act as a valuable tool in clinical orthodontics, implant rehabilitation, and any oral or maxillofacial surgical procedures, where visualization of MVP and its relationship with surrounding structures is a necessity for reaching an accurate diagnosis and patient-specific treatment planning.

Evaluation of experimental resin infiltrant containing nanohydroxyapatite on color stability and microhardness in demineralized enamel.

OBJECTIVE: The aim of the study was to evaluate the effect of the addition of 10% nanohydroxyapatite in an experimental resin infiltrant on color stability and mineral loss. MATERIAL AND METHODS: Bovine enamel blocks were randomized into five groups (n = 27/group): SE (sound enamel); ICL (initial caries lesion); I (Icon®); E (experimental infiltrant); EH (experimental infiltrant containing 10% nanohydroxyapatite). Color evaluation (n = 15) was performed and CIEL*a*b* values were obtained at points T0 (baseline), T1 (14 days immersed on coffee solution), and T2 (28 days immersed) and data were calculated ∆E00, ∆WID, ∆L*, ∆a*, and ∆b*. Cross-sectional microhardness (n = 12) was performed and lesion area (∆S) was calculated. Images were obtained with polarized light optical microscopy at 40 × magnification (n = 5). RESULTS: In color stability results, there was significant difference between time (14 and 28 days); ICL demonstrated significant difference among treated groups in all measures (∆L*, ∆a*, ∆b*, ∆E00, ∆WID) regardless of time; I and E demonstrated similar behavior on those measures and EH differed from I in ∆L*. For ∆S, ICL group showed a significant difference compared to I and EH groups, but did not differ from E. CONCLUSION: The nanohydroxyapatite incorporation suggested an effective mineral recovery on initial caries lesion in depth; however, it showed high color variation, such as Icon. In terms of ∆S, I and EH had lower mineral loss, suggesting a reinforcement on initial caries lesion. CLINICAL RELEVANCE: Commercial and experimental infiltrants containing nanohydroxyapatite present low color stability and might reinforce mineral in initial caries lesion.

The potential of conventional and bulk-fill bioactive composites to inhibit the development of caries lesions around restorations.

PURPOSE: To determine caries inhibition potential of conventional and bulk-fill bioactive composites around restorations. METHODS: Enamel and dentin blocks were prepared using a diamond saw under water irrigation, finished (SiC, 600- and 800-grit) and polished (SiC 1,200, final polish= 0.2 µm). Blocks were then selected through enamel surface microhardness, and enamel and dentin standard cavities were restored (n=10/group) with conventional bioactive composite (Beautifil II, BTF), bulk-fill bioactive composite (Activa BioACTIVE, ACT), glass-ionomer cement (Ionofil Plus, ION), conventional composite (GrandioSO, GSO), and bulk-fill composite (Admira Fusion X-TRA, ADM). Afterwards, the blocks were subjected to pH cycling: 4 hours in demineralization and 20 hours in remineralization solutions for 7 days, before being cut in the middle. One half was used to calculate the carious lesion area (ΔS) using values obtained by cross-sectional microhardness (CSMH) testing. The other half was submitted to polarized light microscopy (PLM) and scanning electron microscopy (SEM). The % of internal gap formation (GAP) of restorations' replicas were analyzed under SEM. Data were analyzed by ANOVA and Tukey test (α= 5%). RESULTS: In terms of CSMH, ION group exhibited the lowest ΔS values, with no significant difference to ADM. The composites BTF and ACT were similar to each other (P< 0.05) and to their negative controls (GSO and ADM), respectively. ION showed lower caries formation under PLM, whereas the GSO group presented a greater demineralized area. ION presented the highest % of internal GAP formation. Bioactive composites (BTF and ACT) were similar to their corresponding conventional ones (GSO and ADM) in terms of GAP formation. CLINICAL SIGNIFICANCE: The glass-ionomer cement was more effective in inhibiting the formation of caries lesions around restorations. Because of the glass-ionomer cement's limited application in high load-bearing areas, the conventional bioactive composite would be a promising clinical choice.

Prevalence and features of elongated styloid process on imaging studies: a systematic review and meta-analysis.

OBJECTIVE: To determine the prevalence of the elongated styloid process (ESP) and its characteristics, such as sex and age of the patient, unilateral and bilateral incidence, besides variations between different populations and panoramic and CBCT examinations. MATERIALS AND METHODS: A search was performed in six databases (PubMed, Web of Science, Scopus, Cochrane, Lilacs, and Embase) to identify observational studies that used imaging exams and assessed ESP prevalence among panoramic radiograph CBCT examinations, whose transversal prevalence studies were included. Furthermore, studies with a specific group of patients or symptomatic patients were excluded. Additionally, Joanna Briggs Institute checklist was used to evaluate the quality of the studies. A meta-analysis was conducted, then subgroup analyses were performed by grouping studies according to the secondary outcomes, with a significance level set at 5%. The Grading of Recommendations Assessment, Development, and Evaluation system was used to rate the certainty in the evidence. RESULTS: The initial search resulted in 1635 studies, from which 39 articles met the inclusion criteria, encompassing 50,655 participants. The sample size varied between 82 and 5,000 participants. The prevalence of the ESP ranged from 1.3 to 94.8%, with an overall prevalence of 30.2%. The bilateral occurrence was higher than the unilateral one, but no significant predilection was observed according to sex, age, or population. The type of imaging examination also showed no difference in its detection. CONCLUSION: The overall prevalence of ESP was 30.2%, with a propensity for bilaterality, but not for any sex, age, or population geographic location. The imaging examination modality did not influence the diagnosis of ESP. However, the quality level of the studies evaluated was very low, demonstrating the need for more homogeneous primary studies on the prevalence of the ESP with a more standardized methodology. CLINICAL RELEVANCE: There is no consensus in the literature regarding the prevalence of the ESP and the characteristics of the affected patients that can cause chronic and debilitating discomfort in the head and neck region. Therefore, knowledge about the prevalence and characteristics of this condition would help dental clinicians reach the correct diagnosis.

Dose-Response Effect of Fluoride Dentifrices on De-/Remineralization of Root Dentine in situ.

The present study aimed to evaluate the effect of fluoride (F) dentifrice with different F concentrations on root dentine de-/remineralization. Ten healthy volunteers took part in this randomized, double-blinded, cross-over, and split-mouth in situ experimental study. During 4 phases of 7 days, they wore a palatal appliance containing 4 bovine dentine blocks (2 sound and 2 with caries) of 4 × 4 × 2 mm. Treatments were performed with silica-based dentifrices containing 0, 700, 1,300, and 5,000 µg F/g (F as NaF). To provide a cariogenic challenge, a 20% sucrose solution was dripped 3 and 8 times daily on the carious-like and sound blocks, respectively. After each experimental phase, the percentage of surface hardness loss (%SHL) or recovery (%SHR) was calculated and the fluoride concentration in the biofilm was determined. The statistical analysis was performed using ANOVA and the Tukey post hoc test with p at 5%. The relationship between variables was analyzed by linear regression. The results showed a lower %SHL when 5,000 µg F/g dentifrice was used but without a statistically significant difference from the conventional one (1,300 µg F/g). Regarding remineralization and F in biofilms, the high-fluoride dentifrice was expressively superior in mineral replacement on the surface and in the F concentration in the biofilms, respectively, compared to the other 3 products (p < 0.05). Also, a significant linear fit between mineral loss/gain, F in biofilms, and fluoride concentration in the dentifrices could be observed. In conclusion, a dose-response F effect was observed, and the high-fluoride dentifrice was effective in enhancing root dentine remineralization in this short-term in situ study.

Chemically Soluble Fluoride in Na2FPO3/CaCO3-Based Toothpaste as an Indicator of Fluoride Bioavailability in Saliva during and after Toothbrushing.

The relationship between the concentration of chemically soluble fluoride found in toothpaste and that present in saliva, during and after brushing, was evaluated as an indicator of potentially bioavailable fluoride in toothpaste. Ten adult participants brushed their teeth with the assigned toothpastes: group I: fresh sample of a fluoride toothpaste: Na2FPO3/CaCO3, 1,378 µg F/g of total soluble fluoride (TSF); groups II-IV: aged samples of toothpaste presenting TSF concentrations of 1,160, 900, and 597 µg F/g, respectively; group V: non-F placebo toothpaste. The volunteers brushed their teeth for 1 min with 0.7 g of the toothpaste, all toothbrushing residues (TR) produced were collected, the mouth was rinsed with water, and saliva samples were collected up to 120 min. Total fluoride (TF) and TSF concentrations were determined in TR and in saliva samples using a fluoride ion-selective electrode. TSF concentration (µg F/mL) in TR was determined as an indicator of fluoride bioavailability during toothbrushing and the areas under curves of saliva fluoride concentration versus time (area under the curve, AUC = µg F/mL × min) were calculated as an indicator of fluoride bioavailability after toothbrushing. A significant correlation was found between the TSF concentrations in the toothpastes and the variables TR (r = 0.850; p = 0.0001) and AUC (r = 0.445; p = 0.004). For TF no significant correlation was found for TR (r = -0.099; p = 0.542) and AUC (r = -0.018; p = 0.912). The findings suggest that TSF concentration chemically found in Na2FPO3/CaCO3-based toothpaste could estimate how much fluoride would be bioavailable in saliva when the teeth are brushed.

Effect of high-fluoride dentifrice and bracket bonding composite material on enamel demineralization in situ.

OBJECTIVE: This in situ study evaluated the effect of high-fluoride dentifrice (5000 µg F-/g) and fluoride-containing bonding composite resin on enamel demineralization adjacent to orthodontic brackets. METHODS: Ten volunteers wore palatal appliances containing bovine enamel blocks with metallic brackets bonded with fluoride-free or fluoride-containing composite resin. During three phases of 14 days each, three dentifrices with different fluoride concentrations (0, 1100, and 5000 µg F-/g) were tested. The cariogenic challenge consisted of 20% sucrose solution dripped 8x/day onto the dental blocks. At the end of each phase, biofilm formed was collected for fluoride analysis. Cross section hardness was performed in enamel blocks, and the lesion area was calculated. Data were analyzed by two-way ANOVA followed by Tukey post hoc test (α = 5%). RESULTS: The only signicant factor for all the variables under study was the dentifrice. Smaller lesion area and higher fluoride concentration on biofilm were found in 5000 µg F-/g group, irrespective of bonding composite resin (p < 0.001). Neither bracket-bonding composite resin nor the interaction between the factors was statistically significant (p > 0.05) for all the variables. CONCLUSION: High-fluoride dentifrice is effective in reducing demineralization on enamel adjacent to orthodontic brackets, while the fluoride-containing bonding composite resin does not influence it. CLINICAL SIGNIFICANCE: Since high-fluoride dentifrice was able to reduce demineralization adjacent to brackets, it can be an option to caries management in orthodontics patients.

Color change, diffusion of hydrogen peroxide, and enamel morphology after in-office bleaching with violet light or nonthermal atmospheric plasma: An in vitro study.

OBJECTIVE: The aim is to evaluate the effect of violet light (VL) and nonthermal atmospheric plasma (NTAP) combined with or without 35% hydrogen peroxide (HP) and 37% carbamide peroxide (CP). METHODS: Bovine crowns were divided into (n = 10) VL, VL/HP, VL/CP, NTAP, NTAP/HP, NTAP/CP, HP, CP, and C (control) groups. Color and whiteness change (CIELAB-Δ Eab, CIEDE2000-Δ E00 , whiteness index-ΔWID ), color parameters (ΔL, Δa, and Δb), and intrapulpal concentration (µL/mL) of HP were assessed by spectrophotometry. Scanning electron microscopy evaluated the morphology of enamel surface. Data were analyzed by two-way analysis of variance and Tukey (Δ Eab , ΔE00 , ΔWID , ΔL, and µL/mL) and Kruskal-Wallis and Mann-Whitney tests (Δ a and Δ b, α = 5%). RESULTS: VL increased ΔEab and ΔWID of CP (P < .05). VL and NTAP alone resulted in perceptible color and whiteness change, but lower than those in the gel-treated groups (P < .05). Activation modes increased ΔL compared with that of C, but only VL enhanced Δb when applied alone or combined with CP. VL and NTAP did not increase HP diffusion (P > .05) or cause alterations in enamel morphology. However, HP and CP promoted topographical changes. CONCLUSION: VL and NTAP changed color to a lesser extent than bleaching gels. VL produced supplementary effectiveness only for CP (ΔEab and ΔWID ), without increasing HP diffusion or changing enamel morphology. CLINICAL SIGNIFICANCE: Although violet LED light and nonthermal atmospheric plasma (NTAP) promoted in vitro perceptible bleaching without compromising enamel morphology, bleaching gels (hydrogen peroxide and carbamide peroxide) were more effective than VL or NTAP. VL or NTAP did not increase intrapulpal diffusion of peroxide.

Root dentine demineralisation according to frequency of sucrose exposure using high-fluoride dentifrice.

OBJECTIVE: To evaluate root dentine demineralisation, biomass and loosely bound fluoride (CaF2 ) concentration according to different frequencies of sucrose exposure using a high-fluoride dentifrice. BACKGROUND: Although high-fluoride dentifrice has been recommended to arrest root dentine lesions, it is not clear whether it can protect dentine from increased frequencies of sucrose exposure. METHODS: An in situ, crossover, split-mouth study was conducted in 3 phases with 7 days each, in which 10 volunteers used a palatal device containing 4 bovine root dentine slabs (2 on each side) with predetermined initial hardness. Cariogenic challenge consisted in dripping a 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/d in each block. Volunteers used high-fluoride dentifrice (NaF, 5000 µg F/g) 3 times/d. After each phase, final hardness was measured and the percentage of surface hardness loss (%SHL) calculated. Also, biomass and CaF2 concentration on dentine were determined. The data were processed and analysed by ANOVA and Tukey test with significance level set at 5%. The relationship between the variables was analysed by linear regression and Pearson correlation (r). RESULTS: %SHL and biomass were significantly greater than control for sucrose frequencies higher than 6 times/d (P < 0.001), while CaF2 concentration decreased from sucrose frequency higher than 2 times/d (P < 0.001). Regression analysis data showed a significant linear fit between sucrose exposure frequency and the studied variables with a strong correlation (r) for %SHL and CaF2 and moderate for biomass (P < 0.05). CONCLUSION: High-fluoride dentifrice is able to reduce root dentine demineralisation if sucrose consumption is not higher than 6 times/d.

Impact of cone-beam computed tomography scan mode on the diagnostic yield of chemically simulated external root resorption.

INTRODUCTION: The aim of this in-vitro study was to evaluate the influence of cone-beam computed tomography scans on the diagnosis of chemically simulated external root resorption. METHODS: One hundred extracted anterior teeth were selected. Subsurface demineralization was induced on a limited area of the apical third of the root of 49 teeth. Each tooth was placed in an empty socket of a partially edentulous dry mandible. Cone-beam computed tomography images were obtained according to 3 protocols: (1) half scan, 0.40-mm voxel size; (2) full scan, 0.40-mm voxel size; and (3) full scan, 0.125-mm voxel size. Three observers evaluated the images. Sensitivity, specificity, accuracy, and area under the curve were compared with the Cochran Q and Mann-Whitney U tests. RESULTS: Protocol 3 had the highest sensitivity (81.63%), accuracy (80.67%), and area under the curve (0.807). There were statistically significant differences between protocol 3 and the other 2 protocols (P <0.001). The specificity of protocol 1 (84.97%) was greater than that of protocols 2 (69.93%) and 3 (79.74%); however, a statistically significant difference was found only between protocols 1 and 2 (P = 0.005). CONCLUSIONS: A more dedicated, high-resolution scan should be acquired when one intends to investigate the early stage of external root resorption during orthodontic treatment. However, this does not imply that all orthodontic patients should be subjected to high-dose cone-beam computed tomography scans.

Evaluation of low fluoride toothpaste using primary enamel and a validated pH-cycling model.

AIM: To develop and validate pH-cycling model for primary enamel, which was then used to evaluate the anti-caries potential of fluoride toothpastes. DESIGN: Human primary enamel slabs were subjected to pH-cycling model for 10 days and maintained for 6 h in demineralizing solution and 18 h in remineralizing solution daily. Twice/day, the slabs were treated. To validate it, the treatments were water or solutions containing 62.5, 125, 250, and 375 µg F/mL. Commercial toothpastes containing no fluoride, 500, 1100, and 1450 µg F/g were evaluated. Demineralization was assessed by percentage of surface hardness loss (%SHL) and cross-sectional hardness (ΔS). Fluoride dose-response effect was analysed by quadratic regression and the effects of toothpastes by Tukey's test. RESULTS: Dose-response effect was found between fluoride concentration and %SHL (R2  = 0.7047; P < 0.01) or ΔS (R2  = 0.4465; P < 0.01). %SHL and ΔS (mean ± SD) for the group treated with 500 µg F/g toothpaste was 36.6 ± 8.0 and 6298.5 ± 1221.3, respectively, which were significantly higher than those treated with 1100 (25.2 ± 8.7; 4565.7 ± 1122) and 1450 µg F/g (24.2 ± 5.2; 2339.1 ± 879.7) toothpastes. CONCLUSION: The developed pH-cycling model may be used to evaluate and compare the anti-caries potential of toothpaste formulations with low fluoride concentration because it presents dose-response effects on the reduction of primary enamel demineralization.

Effect of Fluoride-containing Restorative Materials on Dentin Adhesion and Demineralization of Hard Tissues Adjacent to Restorations.

PURPOSE: This study evaluated (1) the dentin bond strength of fluoridated restorative systems following aging and (2) the enamel/dentin microhardness around restorations after a pH-cycling regimen. MATERIALS AND METHODS: Sixty-four human third molars and four restorative systems were used. A resin-modified glass ionomer (GC Fuji II LC) was used as a fluoride-containing material in the positive control group, while Adper Easy Bond adhesive and Filtek Z350 XT composite resin, which are not fluoridated, were used together in the negative control group. Beautifil II composite resin and FL-Bond II adhesive, both fluoride-containing materials, were compared to Bond Force and Estelite Sigma Quick restorative system, which only contain fluoride in the adhesive. For dentin bond strengths, specimens of each material were fabricated for two test groups (n=8): group 1: tested after 24 h; group 2: tested after 1 year of storage in artificial saliva. Both groups were tested using a microtensile method. For the cross-sectional microhardness test, standardized Class V cavities were prepared and filled with the different restorative systems. After experiencing repeated thermocycling and being subjected to pH-cycling, the teeth were sectioned. The microhardness was measured in enamel and dentin at 50 µm from the cavity wall and at six depths in relation to the surface subjected to pH cycling. RESULTS: None of the restorative systems showed decreased bond strength after storage for one year in artificial saliva. No significant differences in microhardness were observed among the restorative materials on enamel and dentin. CONCLUSION: All the restorative systems evaluated presented stable bond strength after one year of storage. The pH cycling caused a reduction in the superficial enamel microhardness close to the cavity wall. In dentin, the demineralization affected the superficial and sub-surface areas.

In vivo evaluation of fluoride dentifrice and diet control on the demineralization/remineralization process using laser readouts at the margin of the orthodontic bracket/enamel interface.

PURPOSE: To evaluate, in vivo, the effect of fluoride dentifrice and diet control on the demineralization/remineralization processes at the margin of bracket/enamel interface bonded with four different bonding materials, using optical microscopy and fluorescent laser (DIAGNOdent). METHODS: Premolars in 35 subjects (11 to 20 years old) were divided into Group 1 (n = 15) and Group 2 (n = 20). Four bracket/enamel interfaces (near points) and four points at a distance of 2 mm (distant points) were observed. Evaluations were made at the following times: 15 days before bracket bonding (T0), on day of bonding (T1), 1 week after bonding (T2), and 4 weeks after bonding (T3). Subjects received fluoride dentifrice, and toothbrush and were instructed to brush 3x/day, after main meals. Group 1 received the instructions at T1 and Group 2 at T0 and these were reinforced weekly. The Microarch brackets were bonded with four materials: Transbond XT; Concise Ortodôntico; Fuji Ortho LC and Monolok2. DIAGNOdent laser readouts were used for comparison. RESULTS: Data were statistically analyzed by Mann-Whitney, Wilcoxon and Friedman tests (P < 0.05). Higher readouts were found at nearer points than at distant points; Group 2 presented lower readouts than Group 1; No differences were observed among bonding materials.

Full virtual patient generated by artificial intelligence-driven integrated segmentation of craniomaxillofacial structures from CBCT images.

OBJECTIVES: To assess the performance, time-efficiency, and consistency of a convolutional neural network (CNN) based automated approach for integrated segmentation of craniomaxillofacial structures compared with semi-automated method for creating a virtual patient using cone beam computed tomography (CBCT) scans. METHODS: Thirty CBCT scans were selected. Six craniomaxillofacial structures, encompassing the maxillofacial complex bones, maxillary sinus, dentition, mandible, mandibular canal, and pharyngeal airway space, were segmented on these scans using semi-automated and composite of previously validated CNN-based automated segmentation techniques for individual structures. A qualitative assessment of the automated segmentation revealed the need for minor refinements, which were manually corrected. These refined segmentations served as a reference for comparing semi-automated and automated integrated segmentations. RESULTS: The majority of minor adjustments with the automated approach involved under-segmentation of sinus mucosal thickening and regions with reduced bone thickness within the maxillofacial complex. The automated and the semi-automated approaches required an average time of 1.1 min and 48.4 min, respectively. The automated method demonstrated a greater degree of similarity (99.6 %) to the reference than the semi-automated approach (88.3 %). The standard deviation values for all metrics with the automated approach were low, indicating a high consistency. CONCLUSIONS: The CNN-driven integrated segmentation approach proved to be accurate, time-efficient, and consistent for creating a CBCT-derived virtual patient through simultaneous segmentation of craniomaxillofacial structures. CLINICAL RELEVANCE: The creation of a virtual orofacial patient using an automated approach could potentially transform personalized digital workflows. This advancement could be particularly beneficial for treatment planning in a variety of dental and maxillofacial specialties.

Determination of the pubertal growth spurt by artificial intelligence analysis of cervical vertebrae maturation in lateral cephalometric radiographs.

OBJECTIVE: This study aimed to assess the performance of a convolutional neural network (CNN) model in detecting the pubertal growth spurt by analyzing cervical vertebrae maturation (CVM) in lateral cephalometric radiographs (LCRs). STUDY DESIGN: In total, 600 LCRs of patients from 6 to 17 years old were selected. Three radiologists independently and blindly classified the maturation stages of the LCRs and defined the difficulty of each classification. Subsequently, the stage and level of difficulty were determined by consensus. LCRs were distributed between training, validation, and test datasets across 4 CNN-based models. The models' responses were compared with the radiologists' reference standard, and the architecture with the highest success rate was selected for evaluation. Models were developed using full and cropped LCRs with original and simplified maturation classifications. RESULTS: In the simplified classification, the Inception-v3 CNN yielded an accuracy of 74% and 75%, with recall and precision values of 61% and 62%, for full and cropped LCRs, respectively. It achieved 61% and 62% total success rates with full and cropped LCRs, respectively, reaching 72.7% for easy-to-classify cropped cases. CONCLUSION: Overall, the CNN model demonstrated potential for determining the maturation status regarding the pubertal growth spurt through images of the cervical vertebrae. It may be useful as an initial assessment tool or as an aid for optimizing the assessment and treatment decisions of the clinician.

Hydrogen peroxide penetration into the pulp chamber and dental permeability after bleaching.

This study sought to quantify the concentration of hydrogen peroxide (HP) in the pulp chamber and evaluate changes on dental permeability after bleaching with 3 HP concentrations (10%, 35%, and 50%). This study was divided into 2 experiments and the bleaching treatments consisted of 3 applications of HP for 30 minutes during a single session. The first experiment tested HP penetration into the pulp chamber of 4 experimental groups (n = 10) of bovine crowns, which were divided by HP concentration: an unbleached control group (0% HP), 10% HP, 35% HP, and 50% HP. Acetate buffer solution was placed into the pulp chamber and after each application of HP. This solution was collected to determine spectrophotometrically the concentration of HP that reached the pulp chamber. The second experiment evaluated dental permeability. Bovine crowns were divided into 3 groups (n = 10). The crowns were connected to a permeability device and the initial permeability was measured at 10 psi. Three different concentrations of HP gels (10%, 35% and 50%) were applied to the buccal enamel surfaces and the dental permeability was measured after the first, second, and third applications of HP. The data were analyzed by 2-way ANOVA and Tukey test (P ≤ 0.05). All concentrations of HP reached the pulp chamber, although no significant differences were noted between the 3 concentrations tested (P > 0.05). However, the increase of dental permeability in the group that received 50% HP was significantly higher than the 10% HP group (P < 0.05). The results indicate that the HP bleaching treatments increased dental permeability.

Chapter 5.1: Physicochemical Interactions between Enamel and Oral Fluids.

Despite all the current knowledge in cariology, research is still being carried out nowadays trying to make dental enamel resistant to dental caries. Since enamel is mainly composed by a mineral, efforts have been put together to make it more resistant to acids produced by dental biofilm when exposed to dietary sugars. Fluoride was once thought to be a micronutrient that impacted caries resistance when incorporated in the tooth mineral, but we now know that the complex interactions at the mineral surface are most important. Every slightly soluble mineral, and enamel is no exception, has a behavior that is determined by the environment where it is located, and in the case of the dental crown, saliva and biofilm fluid play an important role. Enamel can keep in balance or lose its minerals, but it can gain them back. These processes, equilibrium, and loss or gain follow Le Chatelier's principle, and physicochemically, they are known as saturating, undersaturating, and supersaturating conditions, respectively. Saliva, and even the biofilm fluid, is supersaturated with calcium (Ca2+) and phosphate (PO43-) in relation to enamel solubility, and thus the natural tendency of enamel is to gain mineral, conferring saliva with a remineralizing property. However, the decrease in pH and the presence of free fluoride ion (F-) will determine what will happen to the enamel. While lowering the pH of the medium is an imbalance factor, fluoride at micromolar concentration reduces the acid impact. This chapter provides an updated, evidence-based understanding of the interactions between enamel and oral fluids.

Anticaries potential of a fluoride foam.

Foam has been used worldwide as a vehicle for the professional application of fluoride and hypothetically should have the same anticaries potential as conventional fluoride gel (F-gel) in terms of the formation of reaction products with enamel. Thus, the ability of Flúor Care® foam (FGM, Joinville, SC, Brazil, 12,300 ppm F, acidulated) to react with enamel was evaluated in comparison with Flúor gel® (DFL, Rio de Janeiro, RJ, Brazil, 12,300 ppm F, acidulated). Slabs (n=10/group) of sound enamel and with caries lesion were used, in which the concentrations of total fluoride (TF), and loosely (CaF2-like) and firmly (FAp) bound types were determined. The importance of agitation during application was previously tested. The determinations were made with fluoride ion-specific electrode and the results were expressed in µg F/cm² of the treated enamel area. ANOVA and Tukey tests were used to analyze the difference among treatments, independently for sound and carious enamel. The agitation of the products during application significantly increased the reactivity of the foam (p<0.05), but not that of the gel (p>0.05). The foam did not differ from F-gel (p>0.05) concerning the formation of TF and CaF2-like in sound or carious enamel. Regarding FAp, the foam did not differ from F-gel (p>0.05) in the carious enamel, but the concentration in the sound was lower (p<0.05). The results show that this commercial fluoride foam tested needs to be agitated during application to improve its reactivity with enamel, which raises a question about other brands.