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1.
Med Sci Monit ; 28: e937833, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36071640

RESUMO

BACKGROUND Early pre-eruptive inclination changes of the first premolar (FP) and its associative changes with canine (C) inclination are important to predict canine impaction. This study aimed to evaluate the mesiodistal root angulation of permanent lateral incisors (LI), canines, and first molars by orthopantomogram dental imaging in 296 children ages 6-14 years at a single center in India. MATERIAL AND METHODS The total number of participants was 296, with equal numbers of boys and girls divided into 4 age groups: 6-8 years, 8-10 years, 10-12 years, and 12-14 years. Angles between lateral incisor, erupting canine, and first pre-premolar with midline were measured on an orthopantomogram (dental imaging which includes all the teeth with TMJ). The angle between the erupting C with LI and erupting C with FP was measured. Pearson's correlation was also evaluated between the movement of the erupting canine with lateral incisor and erupting canine with erupting first premolar. RESULTS There was a significant difference in the angular values of different age groups (P≤0.05). The movements between LI, C, and FP were moderately correlated boys and girls aged 6-12 years. CONCLUSIONS The findings from this study showed that in boys and girls aged 6-14 years, eruption of the upper canine tooth was synchronized with eruption of the LI and FP.


Assuntos
Dente Canino , Incisivo , Dente Canino/diagnóstico por imagem , Humanos , Incisivo/diagnóstico por imagem , Dente Molar , Radiografia Panorâmica , Erupção Dentária
2.
Prague Med Rep ; 123(3): 181-187, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36107446

RESUMO

Stroke is a neurological deficit of cerebrovascular origin that promotes physical impairments of adult individuals. The present study is aimed to demonstrate whether hemorrhagic stroke affects the maximum molar bite force. The prospective study carried in Centro Universitario Claretiano de Batatais, Brazil, determined the distribution of the sample into two groups: hemorrhagic stroke group (n=18, median age, 62.5 years) and disease-free group (n=18, median age, 62.0 years), with 10 men and 8 women in each group. Subjects were paired one-to-one (age and body mass index). The dynamometer was used to measure the maximum molar bite force (right and left). All analyses were performed with a significance level of 5% (Student's t-test). Differences were found on the right (p=0.048) and left (p=0.042) molar bite force, with lower bite force (both sides) in hemorrhagic stroke group. The study suggests that hemorrhagic stroke negatively affects the maximum molar bite force and necessitates changes in food intake to nutritious and softer consistency foods.


Assuntos
Força de Mordida , Acidente Vascular Cerebral Hemorrágico , Adulto , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dente Molar , Estudos Prospectivos
5.
BMC Oral Health ; 22(1): 393, 2022 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-36089584

RESUMO

OBJECTIVE: This study aimed to measure the amount of maxillary sinus pneumatization (MSP) extended into alveolar processes in different age groups via cone-beam computed tomography (CBCT) and its association with age. METHODS: The data of 293 adult patients (533 maxillary sinuses) who underwent CBCT at our hospital from January 2020 to October 2020 were analyzed and divided into the following age groups: group I (18-34 years old, youth group), group II (35-59 years old, middle-aged group) and group III (≥ 60 years old, elderly group). The distance between the lowest point of the maxillary sinus floor and nasal cavity floor in the central area of the maxillary posterior teeth was measured and recorded as the amount of MSP. Further, according to the positional relation between the maxillary posterior teeth and maxillary sinus floor, MSP was divided into type I (normal pneumatization) and type II (extensive pneumatization). The distribution of pneumatization types and degree and change of pneumatization for the different age groups were also analyzed. P < 0.05 was used as the threshold for statistical significance. RESULTS: The amount of MSP of group I [(3.75 ± 3.77) mm] was significantly higher than that of group II [(2.30 ± 4.48) mm] and group III [(2.09 ± 4.70) mm], but there was no significant difference between group II and group III. We also found that the amount decreased gradually with increasing age (rs = - 0.2), with the youth group showing a higher prevalence of extensive pneumatization (youth vs. middle-age vs. elderly: 66.44% vs. 36.81% vs. 22.28%, respectively). There was no statistically significant difference in the amount of MSP between males and females and between left and right maxillary sinus in each group (P > 0.05). CONCLUSION: The amount of MSP was significantly higher in the 18-34 years old group compared to older age groups, showed a decreasing trend with age and was not associated with sex and maxillary sinus sides.


Assuntos
Seio Maxilar , Levantamento do Assoalho do Seio Maxilar , Adolescente , Adulto , Idoso , Processo Alveolar , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Humanos , Masculino , Seio Maxilar/diagnóstico por imagem , Pessoa de Meia-Idade , Dente Molar , Adulto Jovem
6.
Am J Biol Anthropol ; 178(3): 437-447, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36110367

RESUMO

Objectives: (1) To investigate sex differences in molar wear in known-age Cayo Santiago rhesus macaques (Macaca mulatta) and, (2) To explore sex differences in body weight and molar eruption timing as factors influencing sex differences in molar wear. Materials and Methods: Data set I comprises wear scores, ages and body weights of 212 living monkeys included in the 1985 roundup. Data set II consists of molar wear measurements taken on 2D images of 103 of these monkeys' dental remains. Ordinal logistic regression was used to analyze the first data set. General linear models were used to analyze the second. Results: Males generally exhibited more wear than females at equivalent chronological ages, though results varied by tooth type for the second data set. Male body weight in the full 1985 living sample was significantly related to dental wear, when age was taken into account; however, when males less than eight years of age were eliminated from the sample, the association between dental wear and weight became statistically insignificant. Analysis of the second data set suggested no statistically significant sex difference in dental wear for third molars, despite the approximately two year sex difference in eruption age for this tooth type. Discussion: This study suggests that body weight in males might be a predictor of dental wear and that if it is, body weight might also influence sex differences in dental wear. Sex differences in dental eruption timing do not appear to explain sex differences in dental wear in this sample.


Assuntos
Dente Molar , Desgaste dos Dentes , Animais , Peso Corporal , Feminino , Macaca mulatta , Masculino , Erupção Dentária
7.
Prog Orthod ; 23(1): 32, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-36089601

RESUMO

BACKGROUND: This study aims to evaluate the impact of the loss of permanent molars on the duration of orthodontic treatment for space closure and without skeletal anchorage. METHODS: Records at the beginning (T0) and the end (T1) of orthodontic treatment were selected retrospectively. Patients were divided into two groups: loss of molar (n = 19) and control, without loss (n = 24). The impact of loss on treatment time was assessed using multiple linear regression adjusted for the number of absences, bonding failures, age, sex, PAR index at T0 and T1 at p<0.05. Treatment time was also evaluated by the number of losses and which arches were involved (upper, lower). The systematic and random errors for the PAR index were verified using the intraclass correlation coefficient (ICC) and the Dahlberg formula, respectively. RESULTS: A small random error (1.51) and excellent replicability (ICC = 99.6) were observed. Overall average treatment time was 22.5 months (± 7.95) for the group without loss and 44.7 months (± 17.3) with a loss. Treatment time was longer in cases where there was a higher number of missing molars and when both arches were involved. In addition to the loss (ß = 4.25, p < 0.001), the number of missed appointments (ß = 2.88, p < 0.001) had a significant effect and increased treatment time. Bonding failures, gender, age, and PAR index at T0 and T1 were not significantly associated with treatment time in the multivariate model (p > 0.05). CONCLUSION: Loss of the first permanent molar has a negative impact on orthodontic treatment time in cases of space closure. The treatment time is longer when there are more tooth losses and arches involved. Treatment time also increases with greater numbers of missed clinical appointments.


Assuntos
Duração da Terapia , Fechamento de Espaço Ortodôntico , Humanos , Maxila , Dente Molar , Estudos Retrospectivos
8.
J Clin Pediatr Dent ; 46(4): 273-279, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-36099230

RESUMO

AIM: To evaluate the clinical and radiographic outcomes of diluted silver diamine fluoride (1:10) and light cure calcium hydroxide as indirect pulp capping agents in primary molars. STUDY DESIGN: Fifty-six primary molars requiring indirect pulp treatment were randomly allocated to two groups: Dilute SDF (one drop of SDF mixed with 9 drops of distilled water giving a 1:10 dilution) and light cure calcium hydroxide. The indirect pulp treatment was followed by glass ionomer cement restoration and all primary molars received stainless steel crown as full coverage restoration. The teeth were followed up both clinically and radiographically at 1,6- and 12-months' time interval using a pre-determined criterion. The results were statistically analyzed using Chi square analysis. The significance level was set at p ≤0.05. RESULTS: Overall clinical and radiographic success rate of indirect pulp treatment with SDF was 96% and with light cure calcium hydroxide was 91.6% respectively at the end of 12 months but the difference was not statistically significant (p>0.05). CONCLUSION: Dilute silver diamine fluoride (1:10) can be advocated as potential indirect pulp capping agent in primary molars with deep carious lesions.


Assuntos
Agentes de Capeamento da Polpa Dentária e Pulpectomia , Hidróxido de Cálcio/uso terapêutico , Fluoretos Tópicos , Humanos , Dente Molar , Agentes de Capeamento da Polpa Dentária e Pulpectomia/uso terapêutico , Compostos de Amônio Quaternário , Compostos de Prata , Dente Decíduo
9.
Zhonghua Yi Xue Za Zhi ; 102(32): 2538-2540, 2022 Aug 30.
Artigo em Chinês | MEDLINE | ID: mdl-36008325

RESUMO

This study aimed to build a home use deep learning segmentation model to identify the scope of caries lesions. A total of 494 caries photographs of molars and premolars collected via endoscopy were selected. Subsequently, these photographs were labeled by physicians and underwent segmentation training by using DeepLabv3+, and then verification and evaluation were performed. The mean accuracy was 0.993, the sensitivity was 0.661, the specificity was 0.997, the Dice coefficient was 0.685, and the intersection over union (IoU) was 0.529. Therefore, the present deep learning segmentation model can identify and segment the scope of caries.


Assuntos
Aprendizado Profundo , Dente Pré-Molar , Suscetibilidade à Cárie Dentária , Dente Molar/patologia
10.
J Dent Child (Chic) ; 89(2): 110-116, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35986471

RESUMO

Purpose: To compare the clinical and radiographic success rates of indirect pulp treatment (IPT) in primary molars using mineral trioxide aggregate (MTA) with and without two percent chlorhexidine gluconate (CHX).
Methods: A blinded, randomized, controlled clinical trial was performed in a split-mouth desi gn. Eighty primary molars in 40 subjects from four to eight years of age were randomly allocated so that each subject had one tooth treated with MTA and CHX and the other tooth treated with MTA alone. Study teeth had deep caries without signs and symptoms of pulpal inflammation or necrosis. All teeth were restored with stainless steel crowns. Follow-up was done at 12 months to evaluate the teeth clinically and radiographically.
Results: At the follow-up, one tooth from each group had failed. Upon the clinical and radiographic evaluations, the overall success rate for both groups was 97 percent. No statistically significant difference was found in the success rate between the two groups.
Conclusions: IPT in primary molars using MTA with or without CHX demonstrated satisfactory clinical and radiographic outcomes in a period of 12 months.


Assuntos
Pulpotomia , Dente Decíduo , Compostos de Alumínio/uso terapêutico , Compostos de Cálcio/uso terapêutico , Clorexidina/análogos & derivados , Combinação de Medicamentos , Humanos , Dente Molar/diagnóstico por imagem , Óxidos/uso terapêutico , Pemetrexede , Silicatos/uso terapêutico , Resultado do Tratamento
11.
Quintessence Int ; 53(8): 698-705, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35976738

RESUMO

OBJECTIVE: To systematically evaluate and meta-analyze the short-and long-term clinical and radiologic failure rates of Biodentine versus formocresol as pulpotomy medicaments in primary teeth. DATA SOURCES: Relevant medical databases were searched until May 2021 for randomized controlled trials that used Biodentine and formocresol as pulpotomy medicaments in primary teeth with deep caries. Primary outcomes included clinical and radiologic failure rates at 12 months. Secondary outcomes were clinical and radiologic failure rates at 3, 6, 9, 13 to 24, and 25 to 48 months. RESULTS: Nine randomized controlled trials (N = 626) with low risk of bias were included. Pooled analysis showed that compared to formocresol, Biodentine had significantly lower clinical failure rates (relative risk [RR] 0.16; 95% confidence interval (CI) 0.03 to 0.87; six randomized controlled trials; N = 394; GRADE, low) and radiologic failure rates (RR 0.19; 95% CI 0.08 to 0.49; six randomized controlled trials; N = 393; GRADE, low) at 12 months. Radiologic failure rates at 6 and 9 months were significantly lower in the Biodentine group compared to the formocresol group. CONCLUSION: Compared to formocresol, Biodentine may be a superior medicament when used for pulpotomy in primary teeth. Adequately powered randomized controlled trials are needed to substantiate this evidence.


Assuntos
Formocresóis , Pulpotomia , Compostos de Cálcio , Combinação de Medicamentos , Formocresóis/uso terapêutico , Humanos , Dente Molar , Silicatos/uso terapêutico , Dente Decíduo
12.
Pediatr Dent ; 44(4): 249-254, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35999682

RESUMO

Purpose: The purpose of this study was to evaluate the clinical retention capabilities of a self-etch adhesive system (experimental group) and conventional acid-etch (control group) techniques and compare the caries incidence within six months and 24 months of follow-up periods. Methods: A total of 47 healthy children with a mean age of 9.7 years and either sound or noncavitated erupted permanent first molars were included in the trial. A total of 188 molars were randomly assigned in a split-mouth design for the self-etch mode in the universal adhesive or conventional acid-etch. Differences in sealant retention and caries incidence were compared at six and 24 months after sealant placement using a chi-square test. Results: Within 24 months of follow-up, the retention of fissure sealant applied using conventional acid etching (41 out of 66; 62.1 percent) was significantly higher (P<0.05) than that of the fissure sealant applied using self-etching mode in the universal adhesive system (17 out of 66; 25.8 percent). There was no significant difference in caries incidence between the two groups up to 24 months after sealant placement. Conclusion: With 24 months of follow-up, the retention of the conventional acid-etching technique were superior to those of the self-etch technique.


Assuntos
Colagem Dentária , Cárie Dentária , Criança , Colagem Dentária/métodos , Cárie Dentária/epidemiologia , Cárie Dentária/prevenção & controle , Seguimentos , Humanos , Dente Molar , Selantes de Fossas e Fissuras/uso terapêutico
13.
Arch Oral Biol ; 142: 105524, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36029738

RESUMO

OBJECTIVES: Enamel prism decussation, which manifests as Hunter-Schreger Bands (HSB), is considered a mechanism to mitigate crack propagation. During the chewing cycle, the 'functional' cusps that are involved in Phase II crushing and grinding experience more complex patterns of stress than do those that 'guide' the molars into occlusion (Phase I). This study examines HSB configuration in the lateral enamel of human molars to identify potential differences between these cusps as predicted from their functional distinctions. DESIGN: Measurements were recorded from scanning electron micrographs of sections through the mesial cusps of unworn permanent molars. For each section, HSB packing density and the relative thickness of decussated enamel were quantified in the cuspal and middle segments of lateral enamel over the guiding and functional cusps. RESULTS: No clear trend from first to third molars in HSB configuration was found in either jaw. In maxillary molars, the functional cusp displays higher HSB packing density in the cuspal and middle segments, and relatively thicker decussated enamel in the cuspal segment than does the guiding cusp. In mandibular molars, the functional cusp displays higher HSB packing density in the middle segment than does the guiding cusp, but no difference in relative thickness was found between them. Enamel of mandibular molars shows weaker decussation than maxillary molars. CONCLUSIONS: The results suggest that guiding cusps are intrinsically more susceptible to crack propagation than functional cusps in human permanent molars. Structural factors such as enamel decussation should be considered when interpreting enamel chipping patterns in dietary contexts.


Assuntos
Esmalte Dentário , Dente Molar , Oclusão Dentária , Humanos , Mastigação , Dente Serotino
14.
Artigo em Inglês | MEDLINE | ID: mdl-36044697

RESUMO

The aim of this retrospective study was to evaluate the effect of free gingival grafts (FGGs) at adjacent mandibular molar implants and to compare the clinical outcomes between the first molar (M1) and second molar (M2) sites. Twenty-one patients with 44 implants were included. At the 3-year follow-up, the mean increase in the keratinized mucosa width (KMW) was 2.35 ± 1.33 mm, and the mean KMW shrinkage rate was 58% ± 23%. M1 sites showed a significantly greater increase of KMW and less graft shrinkage than M2 sites (M1: 2.87 ± 1.40 mm and 49% ± 24%, M2: 1.83 ± 1.06 mm and 66% ± 19%, P < .05). The results show that using FGG to increase KMW in mandibular molar implants was a predictable treatment method, and M1 sites were associated with a greater KMW increase than M2 sites.


Assuntos
Implantação Dentária Endóssea , Implantes Dentários , Implantação Dentária Endóssea/métodos , Gengiva/transplante , Humanos , Dente Molar , Membrana Mucosa , Estudos Retrospectivos
15.
Artigo em Inglês | MEDLINE | ID: mdl-36044701

RESUMO

The high biomechanical loads in molar region wounds challenge the indication for short implants to be used as a single-unit implant. This study reports on the outcomes of single-unit short implants (≤ 8.0 mm) in the maxillary and mandibular molar regions. Forty-nine short implants were placed in 48 patients to replace a missing molar tooth. Two-piece restorations with screw retention were fabricated. During the follow-up, implant survival and marginal bone loss (MBL) were assessed. The known implant length was used as a reference to calibrate the linear measurements on digital periapical radiographs, and descriptive statistical analysis was performed. The implants were followed over a period of 47 ± 12 months. No implant failure was recorded, and no prosthesis failure was observed. The average MBL was 0.15 ± 0.5 mm. The mean crown height space was 13 ± 3 mm. The overall crown-to-implant ratio was 1.7 ± 0.4. Two technical complications occurred due to the loosening of the unit abutment. After screw re-tightening, no more screw loosening was observed. This study supports the use of short implants as a single-unit implant in the maxillary and mandibular molar regions.


Assuntos
Implantes Dentários , Planejamento de Prótese Dentária , Coroas , Implantação Dentária Endóssea , Prótese Dentária Fixada por Implante , Falha de Restauração Dentária , Seguimentos , Humanos , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Estudos Retrospectivos
16.
Braz Dent J ; 33(4): 113-119, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36043563

RESUMO

This study aimed to evaluate the association between the severity of hypomineralized second primary molars (HSPM), molar-incisor hypomineralization (MIH) and dental caries in children. 450 children between the ages of 6 and 7 years were included in this cross-sectional study. A calibrated examiner classified the enamel hypomineralizations and dental caries lesions using the MIH and HSPM and the Nyvad criteria, respectively. The primary outcome was the severity of MIH according to the severity of HSPM. Statistical analysis was performed using the generalized linear model and ordinal logistic regression. The prevalence of concomitant MIH and HSPM was 26% sex and age adjusted. Mild enamel defects were more frequent than severe enamel defects. An association was found between the severity of MIH and HSPM, both for mild defects (OR=87.54; 95%CI: 55.87, 137.17) and severe defects (OR=82.15; 95%CI: 45.72, 147.61). The severity of hypomineralization in permanent molars was associated with the activity of dental caries lesions (OR=29.85; 95%CI: 12.95, 68.83). To conclude, there is a strong association between the severity of HSPM and MIH, which is more significant in the presence of active dental caries lesions.


Assuntos
Cárie Dentária , Hipoplasia do Esmalte Dentário , Criança , Estudos Transversais , Cárie Dentária/epidemiologia , Cárie Dentária/patologia , Esmalte Dentário , Hipoplasia do Esmalte Dentário/epidemiologia , Hipoplasia do Esmalte Dentário/patologia , Humanos , Dente Molar/patologia , Prevalência
17.
Artigo em Inglês | MEDLINE | ID: mdl-35954799

RESUMO

A posterior crossbite is an occlusion disorder that occurs in the transverse plane. It occurs when the buccal cusps of the upper premolars and molars engage lingually with the buccal cusps of the lower teeth. It can be unilateral or bilateral (involving one or more teeth) in the primary, mixed, or permanent dentition. A crossbite may appear in early dentition stages and it can be dental or functional. It can lead to skeletal crossbite in mixed dentition. Therefore, early diagnosis and treatment are crucial. MATERIAL AND METHODS: The selected sample included 204 patients in growing stage divided into two groups: a study group of 102 patients with posterior crossbite and a control group of 102 patients without malocclusion. To analyze the pathology, intraoral frontal photographs and study models were taken, in which the bone component was measured from the Wala Ridge. RESULTS: The use of the photographs to study the Wala Ridge was confirmed. The mean maxillary width was 57.8 mm (SD 1.7) and mandibular width was 56.4 mm (SD 1.7) for the control group, with a maxillomandibular difference of 1.4 mm (SD 0.7); and 52.7 mm (SD 3.7) and 55.5 mm (SD 3.6), respectively, with a maxillomandibular difference of -2.8 mm (SD 1.4) for the study group. A higher maxillomandibular discrepancy was observed in patients with a posterior crossbite that involved more than one tooth in addition to the permanent first molar. It was also higher in patients with bilateral posterior crossbite. CONCLUSIONS: Intraoral frontal photography can be used as a diagnostic method to measure the maxillomandibular difference using the Wala Ridge.


Assuntos
Má Oclusão , Fotografia Dentária , Dentição Mista , Humanos , Má Oclusão/diagnóstico , Má Oclusão/terapia , Maxila , Dente Molar/patologia
18.
BMC Oral Health ; 22(1): 329, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35941577

RESUMO

BACKGROUND: To investigate the anatomic features of three-rooted deciduous mandibular second molars (DMSMs) in Chinese children by using cone-beam computed tomography (CBCT). METHODS: A total of 247 CBCT scans of Chinese children were selected and retrospectively analyzed. The occurrence, gender and side predilection of three-rooted DMSMs were examined. The pattern of concurrence of bilateral three-rooted DMSMs, and concurrence of three-rooted DMSM and three-rooted permanent mandibular first molar (PMFM) was analyzed by the concurrence rate and Spearman's rank correlation test. The geometric parameters of the disto-buccal (DB) and disto-lingual (DL) roots, including the vertical root length, level and angle of distal root furcation, angle of root curvature (by Schneider technique) and the spreading angle, were measured and compared to the three-rooted PMFMs (n = 42) from 100 randomly selected adult subjects. RESULTS: The occurrence of three-rooted DMSMs was 24.0% (54/225) calculated by individual, and 18.6% (88/472) by tooth. A significant right-side predilection was detected (23.0% vs 14.2%, p < 0.05), while gender predilection was not detected (p > 0.05). The bilateral concurrence rate was 49.0%, and Spearman's correlation test indicated a significant relationship between the antimetric teeth (rho = 0.609, p < 0.01); whereas a weak but significant co-relationship was detected between the three-rooted DMSM and three-rooted PMFM (right side: concurrence rate = 31.6%, rho = 0.325, p < 0.01; left side: concurrence rate = 23.0%, rho = 0.260, p < 0.01). The length of DL roots in the DMSMs was 7.4 ± 1.5 mm, and the curvature angle was 16.4 ± 11.3 degrees, which was significantly (both p < 0.01) lower than that of the three-rooted PMFMs (root length = 11.0 ± 1.3 mm; degrees of curvature = 34.2 ± 16.1 degrees), whereas the spreading angle of the DL root in DMSMs (34.6 ± 8.4 degrees) was significantly (p < 0.01) greater than in the PMFMs (26.8 ± 6.5 degrees). CONCLUSIONS: Three-rooted DMSMs have a high occurrence rate in the Chinese children with a right-side predilection, and they have a weak but statistically significant correlation with three-rooted PMFMs. The DL roots of DMSMs are shorter, less curved, and spreading more widely as compared with those in the three-rooted PMFMs.


Assuntos
Cavidade Pulpar , Fragilidade , Dente Molar , Raiz Dentária , Adulto , Criança , China , Tomografia Computadorizada de Feixe Cônico/métodos , Humanos , Mandíbula/diagnóstico por imagem , Dente Molar/diagnóstico por imagem , Estudos Retrospectivos , Raiz Dentária/diagnóstico por imagem
19.
Sci Rep ; 12(1): 13670, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35953552

RESUMO

Bulk-fill composites enable timesaving and less technical-sensitive application of restorations. This study investigated and compared the marginal integrity of classical and bulk-fill composite restorations in primary and permanent molars before and after thermo-mechanical loading (TML). Two Class II cavities were prepared in each of 20 primary and 20 permanent molars. The molars were randomised in four groups for each molar type. Groups 1 and 5 were restored with a high-viscous bulk-fill composite (Tetric PowerFill), groups 2 and 6 were restored with a flowable bulk-fill composite (Tetric PowerFlow), groups 3 and 7 were restored with a high-viscous classical composite (Tetric Prime), and groups 4 and 8 were restored with a flowable classical composite (Tetric EvoFlow). In permanent molars, the flowable composites were covered with a 2-mm layer of high-viscous composite (groups 6 and 8). The restorations were subjected to TML in a custom-made chewing machine (5-50 °C, 2 min dwelling time, × 1000; 400 ,000 loading cycles, 1.7 Hz, 49 N), and quantitative marginal analysis was conducted using scanning electron microscopy. Marginal integrity of each restoration was calculated as a percentage of continuous margins before and after TML. The tested high-viscous bulk-fill restoration showed similarly high marginal integrity in primary and permanent molars as the classical restoration. The tested flowable bulk-fill restoration showed the lowest marginal integrity compared to all other restorations after TML. In contrast to flowable bulk-fill restorations, high-viscous bulk-fill restorations show similar marginal integrity as classical hybrid composite restorations after TML, in both primary and permanent molars.


Assuntos
Resinas Compostas , Dente Molar , Restauração Dentária Permanente , Mastigação , Teste de Materiais , Microscopia Eletrônica de Varredura , Viscosidade
20.
Sci Rep ; 12(1): 13672, 2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-35953700

RESUMO

This study used a novel 3D analysis to longitudinally evaluate orthodontic tooth movement (OTM) and bone morphometry. Twelve-week-old male Wistar rats were subjected to OTM by applying a constant orthodontic force (OF) of 25cN between one of the upper first molars and a mini-screw. In vivo micro-CTs were taken before and after 10, 17, 24 and 31 days of force application, and superimposed by a novel and rigid voxel-based registration method. Then the tooth and alveolar bone segment at different time points became comparable in the same coordinate system, which facilitated the analysis of their dynamic changes in 3D. By comparison between time points and between OF and no OF sides, this study showed that the OTM rate was not constant through time, but conformed to a 'V' shape changing pattern. Besides, OF induced displacement of both loaded and unloaded teeth, and the latter mirrored the former in a delayed manner. In addition, bone morphometric changes synchronized with OTM rate changes, implying that a higher OTM rate was concomitant with more alveolar bone loss. The pressure and tension areas might not be in two opposite sides, but actually adjacent and connected. These findings might provide instructive evidence for both clinical, translational and basic research in orthodontics.


Assuntos
Má Oclusão , Técnicas de Movimentação Dentária , Animais , Osso e Ossos , Masculino , Dente Molar , Osteoclastos , Ratos , Ratos Wistar , Microtomografia por Raio-X/métodos
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