Effect of antioxidants on adhesive bond strength to bleached enamel.

OBJECTIVE: To evaluate the influence of antioxidants (ATX) resveratrol, winter's bark, green tea and yerba mate on the bond strength between bleached enamel and the nanohybrid composite resin. METHODOLOGY: Bovine incisor crowns (n = 132) were randomly divided into 22 groups (n = 6) according to the application times (5, 10, 15, 30, and 60 min) of each antioxidant. Teeth restored without previous bleaching or ATX constituted the non-bleached control group (NB Ctrl) (n = 6), and teeth restored after bleaching and without ATX represented the bleached control group (B Ctrl) (n = 6). The 35 % hydrogen peroxide was applied for 45 min (3 application of 15 min) to the buccal enamel surface. ATX was used after bleaching for the specified time of each group and removed with air-water spray. The enamel was etched with 37 % phosphoric acid (30 s) and rinsed with air-water spray. The adhesive resin was applied to the enamel dry surface. Teeth were restored using 1 mm composite resin increments (10 × 10 × 3 mm) and sectioned in test specimens of 6 mm in length and 1 mm2 in cross-sectional area submitted to microtensile bond strength test (0.5 mm/min). The load (N) at failure was recorded, and the bond strength (σt) was calculated (MPa). The fracture area was analyzed under optical microscopy, and failures were classified as cohesive, mixed, or adhesive. Data was evaluated by Kruskal-Wallis and Dunn tests (p ≤ 0.05). RESULTS: B Ctrl group presented lower σt than NB Ctrl (p < 0.001). Applying resveratrol for 5 or 10 min, winter's bark for 10 or 15 min, green tea for less than 15 min, and yerba mate for 15 min provided similar σt between bleached enamel and nanohybrid composite to the control group. CONCLUSION: Restorative procedures performed immediately after tooth bleaching compromises adhesion. Experimental antioxidants applied to bleached enamel can increase the immediate bond strength of restorations performed directly after bleaching, with similar values to those observed in unbleached enamel. CLINICAL SIGNIFICANCE: This study presents promising results to support the use of antioxidants on the recently bleached enamel to allow adhesive tooth restorations. The immediate bonding obtained using antioxidants was similar to the one achieved in non-bleached enamel in brief application times. Green tea extract and resveratrol were able to restore the bond strength to bleached enamel in a short application time of 5 min. The reduction in the required application time holds the potential to decrease the overall duration of the clinical section, offering clinical advantages and improving the feasibility of using antioxidants on the bleached enamel prior to adhesive procedures.

Choosing Juvéderm Volux™ to chin augmentation: Case report and flowchart for clinical evaluation.

INTRODUCTION: The development of filler biomaterials with high hyaluronic acid concentrations, cohesiveness, and elastic modulus has become an option for chin augmentation, as the balance of these rheological properties promotes high lifting capacity, providing minimally invasive perceptible improvements in patient appearance. PRESENTATION OF CASE: The present study reviewed clinical and anatomical aspects of patients referred for chin augmentation and created a flowchart to assertively diagnose patients with an indication of Juvéderm® Volux™ for defining the lower third of the face. DISCUSSION: The chin is vital for facial proportions and attractiveness perception. Its relevance to facial appearance is noticed the most when chin size is less than ideal, making other facial areas seem larger or smaller. The adjacent soft tissues of the neck and jaw appear prematurely aged when chin projection or width is inadequate. Hyaluronic acid-based fillers have a confirmed history of safe and effective use for treating facial volume loss or deficiency. CONCLUSION: Juvéderm® Volux™ is a safe, effective, and long-lasting alternative for restoring and creating facial volume and sculpting, shaping, and contouring the chin and jaw.

Genotoxicity in the oral cells of older people from a Brazilian rural area: a population-based study.

The purpose of this population-based, observational, and cross-sectional study was to evaluate alterations in the oral cells of a population of older people from a Brazilian rural area, using the micronucleus technique to investigate possible associated genotoxic factors. A questionnaire was applied and clinical examination and collection of oral mucosal cells were performed for all older people (≥ 60 years) from a town in southern Brazil. Demographic and socioeconomic variables, deleterious habits (drinking and tobacco use), presence of gastro-oesophageal reflux disease (GERD), and the use of proton pump inhibitors (PPIs) were considered the exposure variables, whereas metanuclear changes (MCs) and the prevalence of cell micronuclei (MN) were considered outcomes. Out of 489 older people, 447 were included in the study, among whom 50.8% were men with a mean age of 70.9 years and 83.9% had a monthly family income greater than US$ 500.00. GERD symptoms were present in 36.2% of the individuals, and 29.1% used PPIs daily, 53.3% consumed alcoholic beverages, and 46.7% used tobacco. The analysis of 1,000 oral mucosal cells per subject showed a MN frequency of 0-2 per individual, and MCs were detected with an average of 15 units per individual (median = 11 per individual). Poisson regression did not show statistical association between the exposure variables and the outcomes (presence of MN and MCs), except for the use of PPIs, which was a protective factor for the prevalence of MN [PR 0.6 (CI 0.3-0,9)]. Age, sex, family income, tobacco use and drinking, and GERD were not associated with the number of MN and MCs in oral mucosal cells of the investigated older people.

The influence of smoking on the effectiveness of at-home bleaching: A prospective clinical study.

OBJECTIVES: To evaluate the effect of smoking on tooth whitening and color change after at-home bleaching. MATERIALS AND METHODS: This prospective clinical study evaluated two groups of participants: NS-non-smokers (n = 24) and S-smokers (n = 16). All subjects were treated with at-home bleaching using 22% carbamide peroxide (CP) for 1 h/day for 14 days. Color coordinates (L*-luminosity, a*-red-green axis and b*-yellow-blue axis) were obtained before bleaching (D0-baseline), 1 day (D1), 15 days (D15), and 1 month (D30) after bleaching. The whiteness index (WID ) and CIEDE2000 color differences (ΔE00 ) were calculated for S and NS. Color changes between S and NS subjects for specific teeth (CI-Central Incisors, LI-Lateral Incisors, and C-Canines) were analyzed using the Mann-Whitney test (α = 0.05). RESULTS: There was no significant difference in WID between S and NS subjects at baseline. NS participants showed higher WID than S at D1, D15, and D30 (p < 0.05). NS showed higher ΔWID for CI and C between D0 and the other evaluation times (D1, D15, and D30) compared to S. Smokers showed higher darkening of CI than NS in ΔWID D30-D1 (p < 0.05). Color changes showed similar overall behavior for ΔWID . For all evaluation times, ΔWID and ΔE00 values were below the corresponding acceptability thresholds. CONCLUSION: At-home bleaching was effective on smokers and nonsmokers. Smoking negatively affected color stability after bleaching. ΔE00 and ΔWID were acceptable for both groups. CLINICAL SIGNIFICANCE: Although smoking negatively affected color stability after bleaching, the observed changes were clinically acceptable.

Pain factors related to dental implant surgery: A 7-day observational clinical study

This article aims to associate patient-reported pain intensity in the immediate seven days after dental implant surgery with surgical factors, sex and patient age. The sample was composed of 108 patients from a dental school in southern Brazilian, between 2018 and 2020. The variables torque, pre- and postoperative medication, healing of first and second intention, gender, age, number of quadrants, number of implants and type of surgery were related to the outcome pain. Pain was reported every day by the patient until the seventh day after surgery, using a visual analogic scale (VAS). Univariate Poisson regression models were used to assess the relationship among pain and the factors. Rate ratios were obtained with 95% of confidence intervals. Overall pain was reported as moderate/intense (VAS: 3-10) by 30.56% of patients, mild pain (VAS: 1-3) by 55.56%, and no pain symptoms were reported by 13.89% of patients. Individuals which the implants were installed with high torques (50-80 N) showed more pain (p=0.03) compared to patients which the implants were installed with regular torque (30-45 N). The other factors evaluated were not significant. The torque was the most relevant factor related to pain among the evaluated by the study. High torque generates more postoperative pain than lower torque. The factors gender, age, number of operated quadrants, number of installed implants, type of surgery and pre and postoperative analgesic did not interfere in the patient's pain during the first week after surgery.

Genotoxicity in the oral cells of older people from a Brazilian rural area: a population-based study

Abstract The purpose of this population-based, observational, and cross-sectional study was to evaluate alterations in the oral cells of a population of older people from a Brazilian rural area, using the micronucleus technique to investigate possible associated genotoxic factors. A questionnaire was applied and clinical examination and collection of oral mucosal cells were performed for all older people (≥ 60 years) from a town in southern Brazil. Demographic and socioeconomic variables, deleterious habits (drinking and tobacco use), presence of gastro-oesophageal reflux disease (GERD), and the use of proton pump inhibitors (PPIs) were considered the exposure variables, whereas metanuclear changes (MCs) and the prevalence of cell micronuclei (MN) were considered outcomes. Out of 489 older people, 447 were included in the study, among whom 50.8% were men with a mean age of 70.9 years and 83.9% had a monthly family income greater than US$ 500.00. GERD symptoms were present in 36.2% of the individuals, and 29.1% used PPIs daily, 53.3% consumed alcoholic beverages, and 46.7% used tobacco. The analysis of 1,000 oral mucosal cells per subject showed a MN frequency of 0-2 per individual, and MCs were detected with an average of 15 units per individual (median = 11 per individual). Poisson regression did not show statistical association between the exposure variables and the outcomes (presence of MN and MCs), except for the use of PPIs, which was a protective factor for the prevalence of MN [PR 0.6 (CI 0.3-0,9)]. Age, sex, family income, tobacco use and drinking, and GERD were not associated with the number of MN and MCs in oral mucosal cells of the investigated older people.

Influence of photodynamic therapy, different final irrigants, and ultrasonic activation on the bond strength of glass fiber posts to root dentin.

OBJECTIVE: To evaluate the influence of photodynamic therapy (PDT), different final irrigants, and ultrasonic activation (US) on the bond strength of glass fiber posts (GFP) to root dentin. METHODS: One hundred twenty bovine roots were divided into 12 groups according to PDT application, the type of final endodontic irrigant, and US. The samples were divided into 12 groups (n = 10): G1-DW(distilled water); G2-DW+US; G3-17% EDTA; G4-17% EDTA+US; G5-17% GA (glycolic acid); G6-17% GA+US; G7-PDT+DW; G8-PDT+DW+US; G9-PDT+17% EDTA; G10-PDT+17% EDTA+US; G11-PDT+17% GA; G12-PDT+17% GA+US. After cementing the glass fiber posts with resin cement, roots were sectioned into 2-mm-thick slices. One slice from the cervical third and another from the middle third were used for the push out test (PO), and the other two for the diametral compression test (DC). Thus, 10 samples were obtained per third for each mechanical test (n = 10). Kruskal-Wallis and Student-Newman-Keuls tests were used to analyze PO and DC data, and Pearson's correlation test was used to verify the relationship between the variables. Failure patterns were analyzed with chi-square test. RESULTS: Significant differences were found in the PO test among the experimental groups (p < 0.001; power=1.00). PDT improved bond strength when using EDTA. PDT and US increased bond strength when using GA. Favorable failure patterns occurred more frequently in Group GA+US. There was no correlation between data obtained with PO and DC tests (r = 0.112; p = 0.729). CONCLUSION: PDT provided the highest bond strength values of GFP to root dentin when associated with GA and US or when associated only with EDTA.

Mandibular metastasis of primary extrahepatic biliary carcinoma: Case report.

INTRODUCTION AND IMPORTANCE: Cholangiocarcinoma is a malignant neoplasm with a difficult diagnosis and unfavorable prognosis that can appear anywhere in the biliary tree. Anatomically, it can be classified as intra- or extrahepatic, the latter being the most common primary malignancy of the biliary tract. Although bone tissue is the third most common target for metastases in general, metastatic lesions from cholangiocarcinomas are uncommon in the head and neck. CASE PRESENTATION: A 33-year-old female patient undergoing cancer treatment for cholangiocarcinoma was referred to the Oral and Maxillofacial Surgery and Traumatology Service (CTBMF) of the São Vicente de Paulo Hospital in Passo Fundo, Rio Grande do Sul, Brazil, for interdisciplinary follow-up. She presented trismus, dysphagia, pain, necrosis and drainage in the mental region, and an increased volume on the right side of the mandibular body in the region of teeth 47 and 48. An incisional biopsy was performed in this bulging region. The histopathological diagnosis was poorly differentiated carcinoma. The patient was followed-up weekly by the CTBMF team, receiving analgesia and palliative treatment for the extra- and intraoral lesions, controlling opportunistic infections, and improving food intake. DISCUSSION: Metastatic cholangiocarcinomas in the mandible are rare, hence their diagnosis is often late, which may disfavor the prognosis of these conditions. CONCLUSION: Carefully examining patients with mandibular bone lesions is strongly suggested, especially patients with known or previous concomitant malignancy.

Uncommon case of histoplasmosis with oral manifestation: A case report of diagnosis in a South American patient.

INTRODUCTION: Histoplasmosis is a systemic fungal disease caused by the H. capsulatum fungus, which is mainly present in feces and guano of birds and bats. This condition manifests in several ways and it is more severe in its disseminated form and in immunosuppressed patients, putting the patient at risk of death if not diagnosed in time. CASE PRESENTATION: This report presents the case of a 39-year-old white female patient, a seller of agricultural machinery, with a history of lupus erythematosus, who attended a private dental office complaining of a tongue lesion. The patient reported having been subjected to an incisional biopsy of this lesion and the histopathological examination identified an inflammatory process. Considering the inefficient management of the lesion with intralesional application of corticosteroids, squamous cell carcinoma or granulomatous fungal infection was suspected, and a new biopsy was performed allowing the diagnosis of histoplasmosis already spread to the liver, intestines, and bone marrow. The diagnosed disease led the patient to undergo extensive antifungal treatment, including a period of hospitalization. DISCUSSION: The diagnosis of histoplasmosis can be delayed due to several factors, mainly due to its diverse clinical presentation between acute, chronic and disseminated forms. However, achieving an early diagnosis for histoplasmosis is very important to maintain the patient's quality of life. CONCLUSION: Greater education, information, and awareness about histoplasmosis among health professionals are required for managing these cases, especially in endemic areas to H. capsulatum.

Influence of ceramic primers on microshear bond strength to zirconia

This study aimed to investigate the effect of two ceramic primers on the microshear bond strength (µSBS) of yttria-stabilized zirconia (Y-TZP) to two types of self-adhesive resin cement and one BisGMA-based resin cement. Zirconia specimens were sandblasted with 27-µm aluminum oxide and composite cylinders were cemented with resin cement with or without the prior use of ceramic primers. Nine groups (n=12) were randomly distributed according to the cement (self-adhesive RelyX U200/3M ESPE, self-adhesive Maxcem Elite/Kerr, and BisGMA-based dual-cure RelyX ARC/3M ESPE) and ceramic primer (Z-Primer Plus/Bisco and Porcelain Liner M/Sun Medical Co.). After luting, the specimens were stored in distilled water at 37°C for 24 hours and then submitted to the µSBS test. The data were analyzed with two-way ANOVA followed by the Scheffe post hoc test (p<0.05). There were significant differences between RelyX U200 and other groups. There were also significant differences between the RelyX U200 group without ceramic primer and other groups without ceramic primers (p<0.05). Self-adhesive resin cement (RelyX U200 and MaxCem) presented higher microshear bond strength (6.17 and 2.32 MPa) than the conventional resin cement (RelyX ARC) when a porcelain primer was not used (0.43 MPa). When using Porcelain Liner M, the results of RelyX ARC (2.94 MPa) were equivalent to the results of self-adhesive cement (3.93 and 2.11 MPa). When using Z-Prime Plus, the results of MaxCem (5.36 MPa) were lower than those of RelyX U200 (9.59 MPa) but equivalent to those of RelyX ARC (6.07 MPa). When using the RelyX ARC, the use of both ceramic primers improved bond strength to zirconia. When using self-adhesive resin cement, Z-Prime Plus improved microshear bond strength values. It can be concluded that, after 24 hours, the highest µSBS results were obtained when using Z-Prime Plus and RelyX U200 self-adhesive cement.

Influence of smoking on oral cells genotoxicity after at-home bleaching using 22% carbamide peroxide: a cohort study.

OBJECTIVE: This study evaluated the influence of smoking on the oral cells genotoxicity before and after at-home bleaching using 22% carbamide peroxide (CP). MATERIALS AND METHODS: This is a prospective observational analytics cohort study which evaluated nonsmokers (NS; n = 24) and smokers (S; n = 16) patients. At-home bleaching was performed using 22% CP gel in individual trays for 1 h per day for 14 days in both groups. Scrapped cells from marginal gums were collected before the bleaching treatment (D0-baseline) and 1 day (D1), 15 days (D15), and 1 month (D30) after its finishing. Cells were stained with Giemsa 10%, and the micronucleus (MN) and metanuclear alterations (MA) were counted by a trained operator in 1000 cells per patient. The collections and data analysis occurred blindly. Data was analyzed by Kruskal-Wallis, Dunn, and Mann-Whitney test (α = 0.05). RESULTS: MN frequency was not influenced by smoking or bleaching. An increase of MA was observed between D0 and D30 for both groups (p < 0.001); however, no statistical difference was found between NS and S (p > 0.05) in the evaluation times. CONCLUSION: Smoking associated with 22% carbamide peroxide gel for at-home bleaching does not show genotoxic potential analyzed by the MN counts. However, a significant increase of MA was found for smokers and nonsmokers. CLINICAL RELEVANCE: Despite of the increase in MA, smoking associated with 22% CP peroxide at-home bleaching showed no important genotoxic potential (MN) for oral cells. Therefore, at-home bleaching treatment is safe for nonsmokers and smokers even with a high carbamide peroxide concentration of 22%.

Prevalence of red and orange microbial complexes in endodontic-periodontal lesions: a systematic review and meta-analysis.

OBJECTIVE: This systematic review assesses the prevalence of microbial complexes in endodontic-periodontal lesion. MATERIALS AND METHODS: Nine databases were searched through August 2020. Experts were consulted to indicate additional studies. Studies were blindly selected by two reviewers based on pre-defined eligibility criteria. Studies that evaluated the prevalence of microbial orange and red complexes among patients with endodontic-periodontal lesion were considered eligible. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. RESULTS: From 572 articles found on all databases, 11 clinical studies were finally included. The following microorganisms were investigated: P. gingivalis, T. forsythia, T. denticola, F. nucleatum, F. periodonticum, P. micra, P. intermedia, P. nigrescens, S. constellatus, C. gracilis, C. rectus, C. showae and E. nodatum. Considering the orange complex, P. micra, E. nodatum and S. constellatus were prevalent in both root canal and periodontal pockets. P. gingivalis and T. forsythia belonging to the red complex were prevalent only in periodontal pockets. The red complex microorganisms were not found very frequently in root canal. CONCLUSIONS: There is a similarity between the microbiome of root canal and periodontal pockets, with prevalence of the three microorganisms of the orange complex. Two microorganisms from the red complex were prevalent only in periodontal pockets. CLINICAL RELEVANCE: The prevalence of specific microorganisms in endodontic-periodontal lesion is important to understand the microbiological profile of the patients involved and to correlate it with possible clinical and repair conditions of this pathology.

Immunohistochemical analysis of growth factors in platelet-rich fibrin membranes.

The use of autogenous materials to promote tissue regeneration has guided the direction of modern dentistry, and platelet-rich fibrin (PRF) is a promising biomaterial for tissue engineering. This in vitro immunohistochemical study aimed to analyze the presence of factors of endothelial growth and cell differentiation in PRF membranes by using the CD31 (endothelial cells) and CD163 (monocytes) markers. Five men and 5 women, aged between 25 and 60 years and without systemic health problems, were enrolled in the study. Blood samples were collected, submitted to a centrifugation protocol, and fixed in 4% formaldehyde, and then immunohistochemical analysis was performed. The histologic analysis of the slides showed that the fibrin clot was formed by a dense fiber network and cells trapped in its structure. One sample was excluded from the markers testing due to poor quality. All 9 of the valid samples were positive for the CD31 and CD163 markers, with reactivity ranging from 5% to 30% and 10% to 40% of cells, respectively. The immunohistochemical analysis showed the presence of CD31 and CD163 in the PRF membranes, indicating the potential for vascular neoformation and the significant presence of monocytes, which play an important role in tissue remodeling via their differentiation into macrophages.

Quality of life of patients following orthognathic surgery.

The aim of this study was to evaluate how patients with dentofacial deficiency who have undergone orthognathic surgery perceive their quality of life (QoL) with respect to functional, esthetic, and psychosocial issues. In an observational, cross-sectional, descriptive, and quantitative study, 10 patients who had undergone orthognathic surgery answered questionnaires used internationally for assessing QoL: the Short Form Health Survey (SF-36), Oral Health Impact Profile 14 (OHIP-14), and Orthognathic Quality of Life Questionnaire (OQLQ). In addition, the patients completed the Self-Perception Questionnaire of Esteem, Appearance, and Interpersonal Relationships (ASR-26), which explored the differences between their current self-esteem, appearance satisfaction, and interpersonal relationships and their memories of their presurgical feelings about those topics. The data were submitted to descriptive and multivariable statistical analyses. There was a statistically significant difference between the preoperative and postoperative periods regarding self-esteem, appearance satisfaction, and professional relationships (P < 0.05). The data collected with the SF-36, OHIP-14, and OQLQ questionnaires showed high internal consistency (Cronbach α coefficient). The index (mean) scores for the SF-36 (81.5), OHIP-14 (0.6), and OQLQ (5.0) were close to the conditions of high QoL. Principal component analysis revealed 3 distinct groups of patients, and 70% of patients composed a group with high QoL scores, showing no complaints of physical pain, functional limitation, psychological discomfort, social disability, or excessive concern about their oral condition. In this small sample of patients, orthognathic surgery resulted in improved health-related QoL with variations among patients regarding physical pain, psychological discomfort, oral function, facial esthetics, physical function, social function, and self-awareness of facial deformity. The results of this study indicate the importance of applying a questionnaire in individuals who have undergone orthognathic surgery to investigate their personal motivations for treatment and which physical, social, and psychological problems are limiting their QoL.

Orthognathic surgery and orthodontics associated with orofacial harmonization: Case report.

INTRODUCTION AND IMPORTANCE: Orthognathic surgery aims to restore the functional and esthetic standards of the face and non-surgical or minimally invasive procedures have been optimizing the results of facial orthosurgical treatments. This case report aimed to show the use of minimally invasive techniques that, associated with orthognathic surgery, represent a trend in current oral and maxillofacial rehabilitation. CASE PRESENTATION: A female patient, 28 years old, white, sought care from the Dentistry team of the São Vicente de Paulo Hospital, in Passo Fundo, Brazil, complaining of mandibular prognathism, anteroposterior maxillary deficiency, dental crowding, malocclusion, functional and esthetic changes that negatively affected her psychosocial interactions and stomatognathic function. The treatment involved orthodontics, orthognathic surgery, and orofacial harmonization with dermal fillers. CLINICAL DISCUSSION: The multidisciplinarity among the specialties of Oral and Maxillofacial Surgery and Traumatology, Orthodontics, and Orofacial Harmonization add and contribute to the process of planning and implementing the treatment proposed, as well as the prognosis toward patient satisfaction. CONCLUSION: The surgical procedure associated with minimally invasive facial harmonization not only corrected the functional complaint of the patient but also played an important role in improving facial harmony, contributing significantly to self-esteem.

Clinical and satisfaction outcomes of using one or two dental implants for mandibular overdentures: preliminary short-term follow-up of a randomized clinical trial.

OBJECTIVE: This randomized clinical trial aimed to evaluate the marginal bone loss and peri-implant aspects in patients with mandibular overdentures retained by one or two implants and assess patient satisfaction, prosthesis-related clinical outcomes, and masticatory efficiency. METHODS: Patients from the School of Dentistry of the University of Passo Fundo (UPF) with lower conventional complete dentures dissatisfied with prosthetic retention were selected. Eighteen patients were analyzed and divided into randomized treatment groups: GA, installation of one implant in the midline of the mandibular symphysis (8 patients), and GB, installation of two implants in the lower canine region (10 patients). Implant survival and prosthetic maintenance were assessed by clinical and radiographic examinations performed 6 months after implant placement and 3 months after loading. Finally, the masticatory efficiency of the prostheses was evaluated with the QoLIP-10 (Quality of Life with Implant-Prostheses) questionnaire, and the degree of patient satisfaction used the visual analog scale (VAS). RESULTS: Regarding the esthetic satisfaction of the patients, there was no statistical difference between the two groups studied (p = 0.680). Patients who received two implants presented easier chewing (p = 0.049) and a lower average number of prosthesis maintenance. There was no difference between the groups regarding peri-implant bone resorption 3 months after the use of prostheses. CONCLUSIONS: The use of two dental implants showed higher masticatory ability and lower need for maintenance appointments when compared with one implant in mandibular overdentures but did not affect peri-implant aspects and patient satisfaction. The treatment using one implant was effective for the aspects evaluated, but further clinical studies are required on the subject.

Evaluation of apical transportation and apical root sealing in root canals prepared with mtwo rotary system with and without apical enlargement ­ an in vitro study

The aim of this study was to evaluate apical transportation and apical root canal sealing after root canal filling in human teeth prepared with MTwo® Rotary System with and without apical foramen enlargement. Twenty mandibular premolars were divided into two groups (n=10). Group 1 had root canals prepared 1mm beyond the apical foramen. Group 2 had root canals prepared 1mm below the root canal length. After chemo-mechanical preparation, samples were submitted to scanning electronic microscopy. Apical foramen images had 75x magnification at standardized positions, allowing measurements from the apical foramen area before and after root canal preparation, and after root canal filling. Apical foramen shape and apical transportation, as well as its level of circumferential filling after root canal preparation were accessed using the Image Subtraction System. Scanning electronic microscopy analysis demonstrated that samples of Group 1 showed larger foraminal diameter than samples of Group 2 (p<0.05). Apical foramen transportation was statistically different between Groups 1 and 2 (p=0.0108). Furthermore, the apical foramen sealing also differed statistically between groups 1 and 2 (p=0.0007) and 100% of samples of Group 1 showed apical root canal sealing. Apical root canal sealing was more effective when the root canal was prepared with apical foramen enlargement, even when the apical transportation was detected.

Effect of reciprocating instrumentation on chlorhexidine substantivity on human dentin: chemical analysis followed by confocal laser microscopy

The present research analyzed the reciprocating instrumentation associated to chlorhexidine (CHX) substantivity as its correlation with E. faecalis viability in ex vivo root canals. Eighty extracted single-rooted human teeth were used, being 40 to high-performance liquid chromatography (HPLC) and 40 to confocal laser scanning microscopy (CLSM). In both, teeth were decoronated and the cervical third was prepared. In the CLSM analysis, the root canals were inoculated with E. faecalis for 14 days. Samples were divided into 4 groups (n=10) according to instrumentation technique: no instrumentation and irrigation with distilled water (control); manual instrumentation (K-File); rotary instrumentation (ProTaper Next); and reciprocating instrumentation (Reciproc R25). Two percent chlorhexidine was applied as irrigating substance in experimental groups. Longitudinal grooves resulted in 2 halves root and 20 proof bodies in each group. Samples were divided by chance in two groups (n=10) and the outcomes were evaluated after two days and one week. The retained chlorhexidine and live cells after instrumentation techniques in each evaluation time was measured by HPLC and CLSM, respectively. Specific analysis was applied for experimental tests (p≤0.05). Both rotary as well as reciprocating techniques significantly reduced the amount of chlorhexidine on dentin in all observation periods (p<0.05). After evaluation times, all experimental groups presented lower live cells compared to control, but without statistically difference. Intragroup comparisons in times of evaluation showed no differences in instrumentation techniques, in chlorhexidine retention and number of live cells (p>0.05). Reciprocating instrumentation does not interfere on chlorhexidine substantivity.

Testing international techniques for the radiographic assessment of third molar maturation.

BACKGROUND: To assess the radiographic third molar maturation with internationally developed techniques for age estimation. MATERIAL AND METHODS: The study analyzed 1,062 panoramic radiographs of patients treated at the School of Dentistry of the University of Passo Fundo/RS/Brazil, between 2009 and 2020. The patients were separated into ages between 15.00 and 23.99 years and, for each radiograph, the third molars were classified into stages from 1 to 10, with the subsequent application of one of the formulae proposed by Gunst et al. A dichotomous variable indicating whether each individual was younger or older than 18 was calculated from the chronological age of the individuals. A logistic regression model was adjusted to assess whether the third molar stages are correlated with the age of individuals. RESULTS: The error indicators between estimated and chronological ages showed that mean errors closer to zero are seen in the 18-18.9 and 17-17.9 age groups, respectively. Male individuals were earlier in terms of dental mineralization but there were no significant differences between sexes regarding the applicability of the method. The ROC curve shows that the analysis of a single third molar for age estimation gives a maximum of 70.4% reliability. CONCLUSIONS: The moderate performance of the technique tested in the present study justify future country-specific corrections to improve age estimation from the radiographic assessment of third molar maturity. Key words:Dental age estimation, forensic dentistry, radiology, third molar.