Acta odontologica latinoamericana : AOL最新文献

The aim of this study was to analyze the dimensions of the clinical crown of upper central incisors and the prevalence of tooth shapes by two different protocols. Assessment was performed on each of the 111 dental stone type V maxillae models of students of dentistry from Buenos Aires University [93 females and 18 males, mean age 23.70 (± 2.26) years] The mesial and distal-vestibular angles were defined on each right upper incisor, and the following segments were defined: AB (zenith - incisal edge), CD, EF, GH (apical, middle, and incisal thirds - vestibule - mesial and vestibule-distal angles) and their lengths were determined with a precision caliper. Then, the CD/AB, EF/AB and mean CD-EF/AB ratios were calculated. Shapes were assessed by four independent observers, three of whom evaluated digital images of the models, while the fourth had no access to the images, and determined the shapes using an algorithm developed from the dimensions of the studied segments. Rates and confidence intervals were determined, and Fleiss' Kappa was calculated to assess the agreement among the evaluators who worked with the images and among all of them. Average incisor length was 10 mm, and widths at CD and EF were 7.35 mm (0.65) and 8.27 mm (0.58), respectively. Regarding shapes, 51.58% (47.90-55.20) of the incisors were identified as square, 18.02% (14.50-21.90) as ovoid and 30.41% (30.00-30.90) as triangular. Fleiss' Kappa agreement was 0.71 (0.62-0.80). The application of the proposed algorithm provided a considerable level of agreement among the observers. Regarding tooth size, both the average segment length and the proportions were similar to those reported by various authors.

The aim of this study was to determine the frequency and severity of dental fluorosis (DF) and the association between severity and risk factors. In a cross-sectional study, 8- to 12-year-old children, born in a Colombian district, were evaluated according to the Thylstrup and Fejerskov Index (TFI) by two calibrated examiners. Molar Incisor Hypomineralization (MIH) and dental caries (DC) were also evaluated. Ordinal logistic regression was applied (p<0.05). Risk factors and lifestyle factors were collected using a questionnaire answered by parents. DF was detected in 76 (98.7%) of the children (average of 18.4 ±1.81 permanent teeth affected). Grade TF2 was the most frequently observed (34.8%); TF5 was observed in all age groups; TF6- TF7 were observed in 12-year-olds. No association was found between DF severity and DC (Odds Ratio (OR)=1.35; 95%CI: 0.56-3.26) or MIH (OR=1.39; 95%CI: 0.43-4.46). DF severity was significantly associated with use of an indoor wood stove for food preparation (OR = 9.34; 95%CI: 1.11-78.57) and use of a pea-sized volume of toothpaste (OR = 27.42; 95%CI: 1.57-477.36). Prevalence of DC was 38.1% and prevalence of MIH was 14.4%. In this population, the frequency of DF was high and severity was associated with use of an indoor wood stove for food preparation and toothpaste amount used during childhood.

The aim of this study was to conduct a retrospective assessment of the clinical results at 6,12 and 24 months of root coverage in single gingival recessions using coronally positioned flap and acellular dermal matrix allograft. Clinical records were collected from 16 patients with single gingival recessions who visited a private practice in Periodontics in 2005 and 2006. They were treated through a coronally positioned flap and acellular dermal matrix allograft. The following periodontal parameters were recorded at baseline, 6, 12 and 24 months: Recession Depth, Recession Width, Probing Depth, Clinical Attachment Level, Keratinized Tissue Width, Plaque Index, Gingival Index and Sensitivity. The percentage of root coverage was 91.18 ± 21.26 at 6 months, 90.18 ± 22.04 at 12 months and 90.83 ± 18.41 at 24 months. Complete root coverage was 81% (13 out of 16) at 6 and 12 months. At 24 months, complete root coverage was 75% (9 out of 12). The plaque and gingival indexes did not vary significantly between baseline and measurement times. Probing depth was maintained at healthy levels during the months of follow-up. Sensitivity decreased at 12 months (4 of 16) compared to baseline (14 of 16), and was maintained at 2 years (2 of 12). This retrospective study showed that acellular dermal matrix allograft could be considered a useful alternative for the treatment of single gingival recessions, reducing the discomfort and morbidity associated with the palatal donor site.

The aim of this pilot study was to evaluate the impact of the association of free gingival graft (FGG) or collagen-matrix xenograft (CMX) to deproteinized bovine bone graft (DBBG) on the preservation of post-extraction sockets with facial-wall defects. Sixteen patients who presented a maxillary tooth with a facial bone defect and indication of extraction were selected. After the surgical procedure, all the post-extraction sockets were filled with DBBG and covered with a collagen membrane. The cervical part of the socket was then sealed with either FGG or CMX. Clinical and tomographic analyses were performed at baseline and 4 months after the grafting procedure. The FGG sockets showed higher values for the width of the bone ridge than the CMX sockets at 4 months. There was no difference regarding biopsy composition. In conclusion, regardless of the type of soft tissue graft used, socket preservation with DBBG at sites presenting facial bone defects enabled implant placement without further guided bone regeneration, whether the sockets were sealed with FGG or CMX.

Although it has been demonstrated that exposure of lactating rats to CrVI delays tooth eruption, the effects of CrVI exposure on bone remodeling in the developing alveolus during tooth eruption remain unknown. Our purpose was to analyze the effect of CrVI in the alveolus of the first lower molar of rats. Thirty-two suckling Wistar rats were divided into two groups. The experimental group received 12.5 mg/kg body weight/day of potassium dichromate dissolved in saline solution by oral gavage as of day 4 of the experiment; the control group received an equal dose of saline solution. Each group was divided into two sub-sets and euthanized at the ages of 9 and 15 days, respectively. Histochemical and histomorphometric studies of the bone surfaces of the developing tooth alveolus were performed. The percentage of bone formation surfaces was lower in experimental animals than in age-matched controls. The percentage of bone resorption surfaces was significantly lower in 9-day-old experimental rats than in controls and significantly higher in 15-day-old experimental rats than in controls. Exposure to CrVI during lactation alters the sequence of bone resorption and formation in the walls of the developing alveolus, both of which are necessary for tooth eruption, thus causing a delay.

Dental anatomy can vary significantly between different populations from different countries. Dental anatomical variations are of great interest to the dental professional, especially to endodontists, since they can influence the outcome of endodontic treatment. The purpose of the present study was to describe the anatomical variations of the root canal in mandibular first premolars in a population from Colombia, using micro-computed tomography. Fifty mandibular first premolars were scanned on a SkyScan 1174 and the microcomputed tomographic images were reconstructed. Anatomy was assessed using three-dimensional models. The parameters used were: Vertucci's classification, area and volume, perimeter, circularity, and major and minor diameter at 1, 2 and 3 mm from the apical foramen. According to the Vertucci's classification, teeth were classified as: types I (40%), V (24%), VII (4%) and III (4%), with 28% not classifiable. C-shaped canals were found in 1.8% of the sample. Mean evaluations at 1, 2, 3 mm of the foramen were as follows, respectively: perimeter 1.07 ± 0.57, 1.27 ± 0.78 and 1.57 ± 0.84 mm; circularity 0.59 ± 0.19, 0.57 ± 0.20 and 0.56 ± 0.22; maximum diameter 0.41 ± 0.23, 0.48 ± 0.33 and 0.60 ± 0.37 mm; minimum diameter 0.24 ± 0.10, 0.26 0.11 and 0.21 ± 0.13 mm. Mean total area and volume were 61.27 ± 16.47 mm2 and 12.47 ± 4.95 mm3, respectively. There was wide anatomical variation in mandibular first premolars from Colombian individuals, reinforcing the need for proper anatomical knowledge to establish more effective strategies for endodontic treatment.

This study evaluated the impact of COVID-19 on the endodontic treatment routine. It was a cross-sectional study using an online questionnaire applied to endodontists to collect information about practical modifications during endodontic treatment to protect professionals and patients against the COVID-19 outbreak. A total 1105 participants from Brazil participated in the survey. More than 90% of respondents identify the high risk of COVID-19 infection to dentists and the need to change some clinical practices. Most respondents (60.1%) are partially following social isolation. The need for a change in Personal Protective Equipment (PPE) during dental appointments was mentioned by 97.1% of respondents. The use of minimal adequate PPE during the pandemic period was associated with the area of residence and marital status of participants. Only 30% of respondents say they use the minimal adequate PPE. Most respondents will change cavity access preparation to reduce virus dissemination. Other changes in endodontic appointments were described in the survey: greater attention to biosafety measures, duration of dental appointments, and duration of intervals between appointments. Endodontists still need to identify the best arrangement for performing their procedures safely during the COVID-19 pandemic. Specific guidelines require detailed information for each specialty and its procedures.

Dentin hypersensitivity is caused by increased dentinal permeability due to total or partial exposure of dentinal tubules, which in turn can be produced by alterations of dental structures or failure of restorative procedures. The purpose of this in vitro study was to evaluate the efficacy of the application of different kinds of adhesive systems to prevent dentin permeability before and after an erosive challenge. Fifty bovine dentin discs (6x1 mm) were prepared and the specimens were divided into 5 groups (n=10): (SB2) Single Bond 2, (SBU) Universal Single Bond, (CSB) Clearfil SE Bond, (SM) Scotchbond Multipurpose and (C) Control. Hydraulic conductance of dentin was recorded after adhesive application (HC-1) and after erosive challenge (HC-2). Dentin surface images of post-treatment and post-erosive challenge were obtained by scanning electron microscopy (SEM). Data were analyzed using Kruskal Wallis, Mann-Whitney with Bonferroni correction and Wilcoxon tests (p<0.05). Reduction in dentin permeability was observed with the application of adhesive systems (p<0.05). After the erosive challenge, dentin permeability increased for SBU and CSB (p<0.05), while SB2 and SM did not differ in HC-1 or HC-2 (p>0.05). The conventional, self-etching and universal adhesive systems reduce dentinal permeability by more than 80%, and dentin demineralization may contribute to the increased permeability of universal and self-etching systems.

The aim of this study was to evaluate the possible association between the roughness of 5 brands of stainless steel endodontic files and their resistance to fracture due to cyclic fatigue. The study included five different brands of stainless steel endodontic files: SybroEndo Triple-Flex Files (Kerr, Glendora, USA), Ready Steel K-Flexofile (Dentsply Sirona, Ballaigues, Switzerland), Mani Flexile Files (Mani, Tochigi- Ken, Japan), FKG K-Files (FKG, La Chaux-de-Fonds, Switzerland) and Zipperer Flexicut Files (VDW, Munich, Germany). Twelve files per brand (total 60 files) were evaluated. File surface roughness over an area (Sa) was quantified using a focus variation microscope. Then the files were subject to a cyclical fatigue test to determine the number cycles to fracture due to fatigue and length of fractured fragment. Finally, fractographic analysis was performed using a scanning electron microscope. The electropolished Ready Steel K-Flexofile® files had the highest roughness according to Sa parameters, though they also had the highest resistance to fracture due to cyclic fatigue and the longest fractured fragment. Moderate positive correlation was found between fractured fragment length and roughness. The fractured surface showed characteristics of ductile fracture with cracks and plastic deformation. The electropolished stainless steel Ready Steel K-Flexofile® files were the most resistant to fracture due to cyclic fatigue even though they had highest surface roughness.