Relationship between molar incisor hypomineralization, intrapartium medication and illnesses in the first year of life.

Molar incisor hypomineralization (MIH) affects the first permanent molars and permanent incisors whose formative embryological process develops around birth and the first year of life. This study's main objective is to assess the relationship between MIH, on the one hand, with the administration during childbirth of epidural bupivacaine, intramuscular meperidine with haloperidol, synthetic intravenous oxytocin, and prostaglandins such as dinoprostone vaginally, and on the other hand, with suffered pathologies during the first year of life. Cross-sectional retrospective study was carried out on 111 children who attended dental check-ups. Oral examination was carried out to determine MIH involvement. Data on the administration of medications during delivery and the illnesses suffered by the children in the first year of life were taken from the hospital records. Significant relationship with Pearson's chi-square was found between the presence of MIH and the administration of meperidine with haloperidol intramuscularly and the vaginal administration of dinoprostone during labour. Also in children who have suffered serious infections and those who have received antibiotics in early childhood. In recent years there has been a growing trend in many countries to medicalize childbirth even above what the World Health Organization recommends. Some of the drugs used in these protocols could be involved in the appearance of dental mineralization alterations of the MIH type and this would help to explain the increase in its prevalence.

Effect of Biologically Oriented Preparation Technique on the Stress Concentration of Endodontically Treated Upper Central Incisor Restored with Zirconia Crown: 3D-FEA.

The aim of this study was to evaluate the effect of biologically oriented preparation technique on the stress concentration of endodontically treated upper central incisors restored with zirconia crown (yttria-stabilized zirconia polycrystalline ceramic) through finite element analysis (FEA). Four models of maxillary central incisors containing enamel, dentin, periodontal ligament, cortical and medullary bone were created in CAD. Each model received a polymeric core-build up with nanofilled dental resin composite. The evaluated models were SM-preparation in shoulder 90°; CM-chamfer preparation; BOPT-biologically oriented preparation technique and BOPTB-BOPT preparation 1 mm below the cement-enamel junction. All models received zirconia crowns (5Y-TZP), fiberglass post and 1 mm ferrule. The models were imported into the analysis software with parameters for mechanical structural testing using the maximum principal stress and the tensile strength as the analysis criteria. Then, load of 150 N was applied at the cingulum with 45° slope to the long axis of the tooth, with the fixed base for each model. The type of marginal preparation affected the stresses concentration in endodontically treated teeth and in the zirconia crown margin. Considering the stress magnitude only, BOPT is a viable option for anterior monolithic zirconia crowns; however, with the highest stress magnitude at the restoration margin.

Methodology to Quantify and Screen the Demineralization of Teeth by Immersing Them in Acidic Drinks (Orange Juice, Coca-Cola™, and Grape Juice): Evaluation by ICP OES.

Oral health problems may occur as a result of the ingestion of acid drinks. The objective of this in vitro study was to quantify and screen the concentration of potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), iron (Fe), copper (Cu), barium (Ba), lead (Pb), arsenic (As), cadmium (Cd), aluminum (Al), cobalt (Co), chromium (Cr), molybdenum (Mo), sodium (Na), nickel (Ni), selenium (Se), and vanadium (V) released from bovine incisors during an erosive challenge at different times of exposure when immersed in Coca-Cola™, orange juice, and grape juice. A total of 240 samples of bovine incisor teeth were used for the erosive challenge and allocated in groups. Digestion of drinks was performed using microwave-assisted digestion. The content in acidic drinks was monitored before and after the erosive challenge at exposure times of 1, 5, and 60 min using inductively coupled plasma optical emission spectrometry (ICP OES). The drinks' pH varied slightly during the erosive challenge but remained below the critical value of pH 5 to cause tooth demineralization. The concentrations of elements released from the bovine incisors during the in vitro erosive challenge depend on exposure times when immersed in acidic beverages. For some elements such as Ca, Mn, Zn, Fe, Cu, Ba, Pb, As, and Cd, quantified in acidic drinks, grape juice had greater erosive potential than Coca-Cola™ and orange juice. Quantification and monitoring of chemical elements in bovine teeth can be performed considering a longer erosive time and other types of acidic drinks. Further analysis using human teeth is still not available and must be conducted. The demineralization of teeth not only occurs in acidic beverages; physical and chemical factors play other roles and should be investigated.

In Vitro Comparison of Fluoride, Magnesium, and Calcium Phosphate Materials on Prevention of White Spot Lesions around Orthodontic Brackets.

One common negative side effect of orthodontic treatment with fixed appliances is the development of white spot lesions (WSLs) around brackets. This study is aimed at comparing the efficacy of various oral hygiene practices in preventing enamel demineralization around orthodontic brackets under similar in vitro conditions. The study included 90 extracted bovine incisors, which were randomized into six groups: fluoride toothpaste (FT), nonfluoride toothpaste (NFT), fluoride varnish plus fluoride toothpaste (FV+FT), CPP-ACP varnish plus fluoride toothpaste (CPP-ACP+FT), medical minerals gel plus nonfluoride toothpaste (MMG+NFT), and no intervention (control). All groups were subjected to demineralization and remineralization cycles. Visual appraisals were used to evaluate the changes in the enamel surface appearance at the beginning and end of the experiment. The changes in the demineralization degree were evaluated by measuring the Ca+2 concentration in the demineralization solution at different time points. The majority of teeth in the CPP-ACP+FT group exhibited no shift in appearance, whereas in the other groups, a slight change in enamel translucency was observed. At all the time points, the Ca+2 concentration in the demineralization solution in the CPP-ACP+FT group was the least among all other groups. At day 5, MMG+NFT's preventive efficacy was significantly higher than FV+FT's, but at days 10, 15, and 19, their efficacy was similar. However, at all the time points, MMG+NFT's efficacy was significantly higher than that of control, whereas FV+FT's efficacy was decreased at days 10, 15, and 19 and was close to the efficacy of control. To fight WSLs, early diagnosis was of great importance and examination of the tooth surface after air-drying for 5 s was recommended.

Caries removal with Er:YAG laser followed by dentin biomodification with carbodiimide and chitosan: Wettability and surface morphology analysis.

This study aimed to investigate dentin wettability and surface morphology after selective removal of carious lesion by erbium-doped yttrium aluminum garnet (Er:YAG) laser, followed by dentin biomodification with carbodiimide (EDC) and chitosan (CHI). Seventy-eight bovine dentin specimens were submitted to caries induction. Specimens were distributed according to methods of carious removal (n = 39): bur at low-speed (40,000 rpm) or Er:YAG laser (noncontact mode, 250 mJ/pulse and 4Hz). All specimens were etched with 35% phosphoric acid, and subdivided according to dentin biomodification (n = 13): Control (no biomodification), EDC or CHI. The contact angle (n = 10) between adhesive system (3M ESPE) and dentin surface was measured by a goniometer. Eighteen specimens (n = 3) were analyzed by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey's test (α = .05). The method used to remove carious lesion did not influence the wettability of dentinal surface (p = .748). The angles produced on the remaining dentin after biomodification were influenced (p = .007). CHI promoted higher contact angles (p = .007) and EDC did not differ from the control group (p = .586). In the bur-treated group, most tubules were open, regardless of which biomodifier was used. Laser modified the organic matrix layer. CHI promoted partially closed tubules in some areas while EDC exposed dentinal tubules. Regardless of which method was used for selective removal of carious lesion, biomodification with EDC did not affect the dentin wettability, whereas CHI changed the wettability of remaining dentin. Both biomodifiers promoted a slight change on dentin morphology.

Influence of Trigonella foenum graecum seed extract as root canal irrigation agent on root surfaces: A scanning electron microscope/energy dispersive X-ray analysis study.

The purpose of this in vitro study was to investigate the effect of Trigonella foenum graecum seed extract (TFGSE) as a root canal irrigation agent on the surface of instrumented root canals and on changes in the mineral contents of the root dentin. A total of 90 extracted human mature maxillary central incisor teeth with a single root and without root resorption were selected. The specimens were subdivided into five groups according to irrigation protocol groups G0: distilled water (n = 15): G1: Sodium hypochlorite (5.25% NaOCl); G2: 1% TFGSE G3: NaOCl +17% EDTA (3 min); G4: NaOCl+1% TFGSE; G5: 1% TFGSE +17% EDTA. All the roots were sectioned longitudinally into two halves and examined under scanning electron microscope/energy dispersive X-ray analysis (SEM/EDX) to assess changes in the mineral content of the tooth. Smear layer removal from root canals was evaluated with scanning electron microscopy (SEM). A statistical analysis was performed using the Kruskal-Wallis test. The most effective irrigation protocols in removing smear layer occurred with TFGSE and NaOCl, both with rinsing with 17% EDTA. TFGSE was more effective than NaOCl for removing the smear layer. The results showed the ability of 1% TFGSE to remove the smear layer from the root canals. TFGSE is a promising alternative irrigation agent for root canals.

The effect of NaOCl and heat treatment on static and dynamic mechanical properties and chemical changes of dentine.

OBJECTIVES: To determine the effect of heat on flexural strength (FS), maximum strain (MS), storage modulus (SM), tan delta (TD) and chemical changes through micro-Raman spectroscopy of dentine exposed to 2.5% NaOCl or saline. METHOD: ology: Dentine bars were randomly allocated to 8 test groups. Half (groups 2,4,6,8) were treated with NaOCl for 20 min; the rest (groups 1,3,5,7) remained in saline. FS/MS were measured in groups 1-4 (n = 15) (3/4 were also heated to 200 °C & re-hydrated in saline). Micro-Raman spectroscopy was performed on bars from groups 1-4. SM/TD were measured in 5-8: in 5/6 (n = 10), repeated after heating (200 °C), then following re-hydration; in 7/8 (n = 3) after heating to 25-185 °C. RESULTS: Increase in MS on heat and FS/MS on heat + NaOCl was not significant (P > 0.05). SM increased (P = 0.06) after heat treatment but reduced to initial state after rehydration (P = 0.03). TD did not change (P = 0.4) after heat (200 °C) treatment but rehydration increased it compared with pre-treatment state (P = 0.001). For dentine bars pre-treated with NaOCl, SM did not change (P = 0.6) after heat (200 °C) treatment or rehydration but TD significantly increased (P = 0.02) upon re-hydration compared with pre- (P=0.007), or post- (P = 0.03) heat-treatment states. SM and TD varied between 25-185 °C with no consistent trend amongst the NaOCl pre-treated bars. Micro-Raman only detected chemical changes following NaOCl treatment in the mineral phase. CONCLUSIONS: Exposure of dentine bars to heat and NaOCl produced only moderate changes to quasi-static but marked changes to viscoelastic properties, which may be explained by chemical alterations.

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial.

OBJECTIVE: To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. MATERIALS AND METHODS: 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). RESULTS: Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). CONCLUSIONS: Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

The effect of cadmium exposition on the structure and mechanical properties of rat incisors.

Alterations in the structure and mechanical properties of teeth in adult Wistar rats exposed to cadmium were investigated. Analyses were conducted on two sets of incisors from female and male specimens, that were intoxicated with cadmium (n = 12) or belonged to the control (n = 12). The cadmium group was administered with CdCl2 dissolved in drinking water with a dose of 4mg/kgbw for 10 weeks. The oral intake of cadmium by adult rats led to the range of structural changes in enamel morphology and its mechanical features. A significant increase of cadmium levels in the teeth in comparison to the control, a slight shift in the colour and reduction of pigmented enamel length, higher surface irregularity, a decrease of hydroxyapatite crystals size in the c-axis and simultaneous increase in pigmented enamel hardness were observed. The extent of these changes was sex-dependent and was more pronounced in males.

Microsphere controlled drug delivery for local control of tooth movement.

Background: Because orthodontic tooth movement is dependent upon osteoclast-mediated resorption of alveolar bone adjacent to the pressure side of tooth roots, biologic mediators that regulate osteoclasts can be utilized to control tooth movement. Objectives: To develop a novel method to locally enhance orthodontic anchorage. Methods: We encapsulated osteoprotegerin (OPG) in polymer microspheres and tested the effectiveness of microsphere encapsulated versus non-encapsulated OPG for enhancing orthodontic anchorage in a rodent model of tooth movement. A single injection of 1 mg/kg non-encapsulated or microsphere encapsulated OPG was delivered into the palatal mucosa mesial to the first maxillary molar 1 day prior to tooth movement. A positive control group received injections of 5 mg/kg non-encapsulated OPG every 3 days during tooth movement. After 28 days of tooth movement, hemi-maxillae and femurs were dissected. Molar mesial and incisor distal tooth movement was measured using stone casts that were scanned and magnified. Local alveolar, distant femur bone, and tooth root volumes were analyzed by micro computed tomography. Serum OPG levels were measured by ELISA. Osteoclast numbers were quantified by histomorphometry. Results: The single injection of microsphere encapsulated OPG significantly enhanced orthodontic anchorage, while the single injection of non-encapsulated OPG did not. Injection of encapsulated OPG inhibited molar mesial movement but did not inhibit incisor tooth movement, and did not alter alveolar or femur bone volume fraction, density, or mineral content. Multiple injections of 5 mg/kg non-encapsulated OPG enhanced orthodontic anchorage, but also inhibited incisor retraction and altered alveolar and femur bone quality parameters. Increased OPG levels were found only in animals receiving multiple injections of non-encapsulated 5 mg/kg OPG. Osteoclast numbers were higher upon tooth movement in animals that did not receive OPG. Osteoclast numbers in OPG injected animals were variable within groups. Conclusions: Microsphere encapsulation of OPG allows for controlled drug release, and enhances site-specific orthodontic anchorage without systemic side effects. With additional refinements, this drug delivery system could be applicable to a broad array of potential biologic orthodontic therapeutics.

Effect of dental bleaching on pulp oxygen saturation in maxillary central incisors - a randomized clinical trial

Abstract Objective To assess pulp oxygen saturation levels (SaO2) in maxillary central incisors after dental bleaching. Materials and Methods 80 participants (160 teeth) were randomly allocated to four groups: G1 In-office bleaching with two applications of 35% hydrogen peroxide (HP) (20 minutes), followed by at-home bleaching with 10% carbamide peroxide (CP) (2 hours/day for 16 days); G2 - Same protocol as G1, plus desensitizing toothpaste; G3 - In-office bleaching with 35% HP and one application of placebo gel (20 minutes), followed by at-home bleaching with 10% CP (2 hours/day for 16 days); and G4 - Same protocol as G3, plus desensitizing toothpaste. Pulp SaO2 levels were measured before (T0) and immediately after (T1) in-office bleaching; on the 5th (T2), 8th (T3), 12th (T4), and 16th days of at-home bleaching (T5); and on the 7th (T6) and 30th (T7) days. Mean (SD) pulp SaO2 levels were compared within groups by generalized estimating equations (GEE) and Student's t-test (P<0.05). Results Mean pulp SaO2 at T0 was 84.29% in G1, 84.38% in G2, 84.79% in G3, and 85.83% in G4. At T1, these values decreased to 81.96%, 82.06%, 82.19%, and 81.15% in G1, G2, G3, and G4 respectively, with significant difference in G4 (P<0.05). During home bleaching, pulp SaO2 levels varied in all groups, with 86.55%, 86.60%, 85.71%, and 87.15% means at T7 for G1, G2, G3, and G4, respectively; G2 presented significant difference (P<0.05). Conclusions Pulp SaO2 level in maxillary central incisors was similar at baseline, reducing immediately after in-office bleaching, regardless of using desensitizing toothpaste and increasing at 30 days after dental bleaching.

Tissue preservation through socket-shield technique and platelet-rich fibrin in immediate implant placement: A case report.

RATIONALE: In this report, a combination of socket-shield technique (SST) and platelet-rich fibrin (PRF) technique was used for immediate implant placement on a fractured central incisor. During the follow-up visit, cone beam computed tomography (CBCT) and clinical observation were used to evaluate the preservation outcome of peri-implant bone and gingiva. PATIENT CONCERNS: The patient was a 28-year-old healthy female patient who desired her fractured 21 to be replaced with an implant-supported single crown; the fractured 21 comprised a post-core crown with insufficient residual bone at the labial site. DIAGNOSIS: The root of 21 exhibited a complex root fracture; the labial portion of the alveolar ridge was thin (<1 mm) and partial ankylosis of the residual root was observed. INTERVENTIONS: Modified SST was applied to the labial portion of the residual root. The implant was placed immediately at the lingual site of the retained socket-shield root fragment; PRF was the placed in the gap between the root fragment and the implant. Final prosthodontic treatment was performed at 24 weeks after implant placement. OUTCOMES: Clinical examination and CBCT scanning at various follow-up visits time showed that the periodontal tissue was well- preserved. At 6 months after surgery, the average horizontal and vertical peri-implant bone resorption was 0.4 mm; a follow-up visit at 18 months post-loading indicated that peri-implant tissue was well preserved by the shield-technique and no significant peri-implant tissue resorption was displayed. LESSON SUBSECTIONS: In cases of anterior teeth with intact but insufficient residual alveolar ridge, the SST with PRF may be effective for preservation and maintenance of stable peri-implant tissue.

Effect of At-Home Bleaching on Oxygen Saturation Levels in the Dental Pulp of Maxillary Central Incisors.

The present study assessed oxygen saturation (SaO2) levels before, during, and after at-home bleaching treatment in the pulps of healthy maxillary central incisors. SaO2 levels were measured in 136 healthy maxillary central incisors using a pulse oximeter. The bleaching protocol consisted of 10% carbamide peroxide gel placed in individual trays and used for four hours daily for 14 days. SaO2 levels were assessed before bleaching (T0), immediately after the first session (T1), on the 7th day of treatment (T2), on the 15th day (the day following the last session) (T3), and 30 days after completion of the bleaching protocol (T4). Data were statistically analyzed using generalized estimating equations (GEE), Student's t test (p<0.05) and Pearson's correlation. Mean pulp SaO2 levels were 85.1% at T0, 84.9% at T1, 84.7% at T2, 84.3% at T3, and 85.0% at T4. Gradual reductions in SaO2 levels were observed, with significant differences (p<0.001) during the course of home bleaching treatment. However, 30 days after the end of the bleaching protocol, SaO2 levels returned to baseline levels. Home bleaching caused a reversible transient decrease in SaO2 levels in the pulps.

Effect of at-home bleaching on oxygen saturation levels in the dental pulp of maxillary central incisors

Abstract The present study assessed oxygen saturation (SaO2) levels before, during, and after at-home bleaching treatment in the pulps of healthy maxillary central incisors. SaO2 levels were measured in 136 healthy maxillary central incisors using a pulse oximeter. The bleaching protocol consisted of 10% carbamide peroxide gel placed in individual trays and used for four hours daily for 14 days. SaO2 levels were assessed before bleaching (T0), immediately after the first session (T1), on the 7th day of treatment (T2), on the 15th day (the day following the last session) (T3), and 30 days after completion of the bleaching protocol (T4). Data were statistically analyzed using generalized estimating equations (GEE), Student's t test (p<0.05) and Pearson's correlation. Mean pulp SaO2 levels were 85.1% at T0, 84.9% at T1, 84.7% at T2, 84.3% at T3, and 85.0% at T4. Gradual reductions in SaO2 levels were observed, with significant differences (p<0.001) during the course of home bleaching treatment. However, 30 days after the end of the bleaching protocol, SaO2 levels returned to baseline levels. Home bleaching caused a reversible transient decrease in SaO2 levels in the pulps.

Resumo Este estudo verificou o grau de saturação de oxigênio (SaO2) pulpar antes, durante e após o clareamento dental caseiro em incisivos centrais superiores hígidos. O nível de SaO2 foi verificado em 136 incisivos centrais superiores hígidos usando oxímetro de pulso. A técnica de clareamento empregou peróxido de carbamida 10% em moldeira individual por quatro horas diárias durante 14 dias. Os níveis de SaO2 foram analisados antes do clareamento (T0), imediatamente após a primeira sessão (T1), no sétimo dia de tratamento (T2), no décimo quinto dia (um dia após a última sessão) (T3) e 30 dias após o término do clareamento dental (T4). A análise estatística utilizou o modelo de equações de estimações generalizadas (GEE), teste t de Student (p<0,05) e correlação de Pearson. Os níveis médios de SaO2 pulpar foram 85,1% em T0, 84,9% em T1, 84,7% em T2, 84,3% em T3 e 85,0% em T4. Foi observada uma redução gradual dos níveis de SaO2, com diferenças significantes (p<0,001) durante o clareamento dental caseiro. No entanto, 30 dias após o término do clareamento dental, houve retorno aos valores iniciais. O clareamento dental caseiro provocou uma diminuição transitória reversível no grau de SaO2 pulpar.

Effect of a dentifrice containing nanohydroxyapatite on the roughness, color, lightness, and brightness of dental enamel subjected to a demineralization challenge.

The dental profession is still pursuing the most effective way to treat white-spot lesions in order to produce a sound and esthetically pleasing enamel surface. The aim of the present research was to evaluate in vitro the effects of a dentifrice with nanohydroxyapatite (nano-HAp) on the roughness, color, lightness, and brightness (gloss) of bovine enamel subjected to pH cycling. Twelve enamel discs prepared from bovine incisors were divided into 2 experimental groups: dentifrice with sodium fluoride (Colgate Total 12 Clean Mint) and dentifrice with nanoHAp (Megasonex). For 14 days, the specimens were subjected to 30 cycles of simulated brushing twice a day as well as to a pH cycling model (6 hours of demineralization and 18 hours of remineralization daily). The roughness, color, lightness, and brightness of all specimens were evaluated at baseline (immediately after specimen preparation) and after 7 and 14 days of treatment. A Tukey test demonstrated that there were no statistically significant differences in the effects of the dentifrices on any parameter after 7 days (P > 0.05). After 14 days, however, there was a statistically significant increase in mean roughness in the group brushed with fluoride dentifrice (P < 0.05). Thus, the nanoHAp containing dentifrice promoted less superficial roughness after 14 days, but both dentifrices were similar in relation to color variation, lightness, and brightness.

Effect of the calcium silicate-based sealer removal protocols and time-point of acid etching on the dentin adhesive interface.

The aim of the study was to evaluate the effects when acid etching on the dentin surface was immediately performed (I) or 7 days (D) after calcium silicate-based sealer (MTA Fillapex) removal, using 95% ethanol (E) or xylol (X). First study, 60 bovine incisor dentin specimens were impregnated with sealer and divided into six groups (n = 10): (EI), E + I; (XI), X + I; (ED), E + D; (XD), X + D, (UN), untreated and (MR), mechanical removal of sealer. Scanning electron microscopy (SEM) images (500×) were obtained from each specimen and scores assessed the sealer residues persistence. Second study, 60 specimens were similarly treated; however, the specimens were restored with composite resin after the removal protocols. Hybrid layer formation was evaluated using confocal laser microscopy (1,024×). Third study, 60 specimens were similarly obtained and subjected to micro-shear test to evaluate the effects of removal protocols on the bond strength of etch-and- rinse adhesive system to dentin. XI showed the highest persistence of sealer residues (p < .05), similar to MR (p > .05). EI showed the greatest hybrid layer extension, except in relation to UN (p < .05). XI and MR presented the lowest bond strength adhesive system to dentin (p < .05). Acid etching immediately after calcium silicate-based endodontic sealer removal using xylol presented the highest residues persistence and negatively affected the adhesive interface between dentin and etch-and-rinse adhesive system.

The effect of a single injection of irinotecan on the development of enamel in the Wistar rats.

Cancer is the second most frequent cause of death in children. Because the prognosis for childhood malignancies has improved, attention has now focused on long-term consequences of cancer treatment. The immediate effects of chemotherapy on soft tissues have been well described; however, there is less information about long-term effects of chemotherapy on the development of dental tissues. To test the association between the effect of chemotherapy on enamel development, we examined two groups of rats: one that had received an intraperitoneal dose of 200 mg/kg of irinotecan, whereas the other (control) group had received vehicle only. Rats were killed at 6, 48 and 96 hr post-injection; the mandibles dissected out, fixed for histological evaluation and scanned for mineralization defects by Micro-CT. Our results showed structural changes in the ameloblast layer along with a significant reduction in mineralization and thickness of enamel at 96 hr after chemotherapy. These data demonstrate that irinotecan induces structural changes in forming enamel that become apparent after anticancer chemotherapy treatment.

Efficacy of different carriers for the triple antibiotic powder during regenerative endodontic procedures.

Chemical debridement during Regenerative Endodontic procedures is important. Previous research studies have evaluated various antibiotics and their concentrations but none have addressed the concern of delivering these materials. Hence, the purpose of this study was to determine what carrier could be used effectively in a clinical setting. Sixty caries-free maxillary incisors were used and inoculated with Enterococcus faecalis and divided into positive and irrigation controls and experimental groups that had triple antibiotic powder (1:1:1 ciprofloxacin:metronidazole:minocycline) delivered using various carriers: saline, cotton, sponge and methylcellulose. Current AAE regenerative protocols were followed. S2 sampling was performed and tested for bacterial presence via culturing and SEM. The results demonstrated that saline was the most effective carrier for the triple antibiotic powder while cotton and sponge were most ineffective. Saline and methylcellulose both reduced bacterial counts to a significant level. Overall, this study demonstrated that saline as a carrier was most effective and should be routinely used.

The performance of probiotic fermented sheep milk and ice cream sheep milk in inhibiting enamel mineral loss.

The study aimed to evaluate the effects of two different sheep milk-based food matrices - fermented sheep milk and ice cream - with added probiotic bacteria (Lactobacillus casei 431) on dental enamel subjected to an in vitro highly cariogenic challenge. Sixty enamel blocks were selected and randomly allocated into five treatment groups (n=12): conventional fermented sheep milk (CFSM), probiotic fermented sheep milk (PFSM), conventional sheep milk ice cream (CSMIC), probiotic sheep milk ice cream (PSMIC) and control using deionized water. The blocks were subjected to highly cariogenic pH cycling and the products were applied (5min), in a blinded way, once a day to simulate a daily use for 8 consecutive days. A microhardness test was performed before and after the treatment to estimate the percentage of microhardness surface loss (% SML). Scanning electronic microscopy (SEM) was performed to confirm the mineral loss. All groups had lost microhardness after the experiment. However, CFSM and PFSM exhibited the most positive findings when compared to the control in both ice creams. Scanning electron microscopy showed less mineral loss in CFSM and PFSM compared with CSMIC, PSMIC and control after the cariogenic challenge. Overall, fermented milk decreased mineral loss from enamel subjected to a highly cariogenic challenge, regardless of the presence of probiotics in their composition, which had a higher efficacy compared to ice cream.

Biomechanical Evaluation of a Tooth Restored with High Performance Polymer PEKK Post-Core System: A 3D Finite Element Analysis.

The aim of this study was to evaluate the biomechanical behavior and long-term safety of high performance polymer PEKK as an intraradicular dental post-core material through comparative finite element analysis (FEA) with other conventional post-core materials. A 3D FEA model of a maxillary central incisor was constructed. A cyclic loading force of 50 N was applied at an angle of 45° to the longitudinal axis of the tooth at the palatal surface of the crown. For comparison with traditionally used post-core materials, three materials (gold, fiberglass, and PEKK) were simulated to determine their post-core properties. PEKK, with a lower elastic modulus than root dentin, showed comparably high failure resistance and a more favorable stress distribution than conventional post-core material. However, the PEKK post-core system showed a higher probability of debonding and crown failure under long-term cyclic loading than the metal or fiberglass post-core systems.