Impact of Dental Aesthetic Index characteristics on the severity levels of malocclusion in a non-White population.

INTRODUCTION: This study evaluated the impact of the esthetic and occlusal characteristics of the Dental Aesthetic Index (DAI) on the need for orthodontic treatment in a non-White population. METHODS: A cross-sectional study was conducted with 1296 non-White adolescents aged 12 years. DAI was the outcome variable (DAI 1 and 2 and DAI 3 and 4). The independent variables were categorized on the basis of the occlusal esthetic characteristics evaluated by DAI (tooth absence, crowding, spacing, midline diastema, maxillary misalignment, mandibular misalignment, maxillary anterior overjet, mandibular overjet, anterior open bite, and anteroposterior molar relationship). Simple logistic regression models were adjusted for the outcome, and the raw odds ratios were estimated. Variables with a P value of <0.20 for individual analyses were tested in a multiple logistic regression model, with P ≤0.05 remaining. RESULTS: A total of 1296 adolescents (764 girls and 532 boys) were evaluated; 1067 (82.3%) had DAI 1 or 2 (minor to a moderate need for orthodontic treatment), and 229 (17.7%) had DAI 3 or 4 (defined need for orthodontic treatment). The results showed that adolescents with diastema, maxillary irregularity, mandibular irregularity, mandibular overjet, anterior open bite, and the altered molar relationship had 5.34, 2.36, 2.63, 3.56, 8.73, and 5.16 times more likelihood to have DAI 3 or 4 (P ≤0.05), respectively. CONCLUSIONS: Diastema, maxillary and mandibular misalignment, mandibular overjet, anterior open bite, and anteroposterior molar relationship were the characteristics that influenced the determination of the need for orthodontic treatment in a non-White population using the DAI index.

Oral and maxillofacial outcomes in children with microcephaly associated with the congenital Zika syndrome.

INTRODUCTION: The objective of this study is to assess the oral and maxillofacial characteristics of microcephalic children associated with congenital Zika syndrome (CZS). METHODS: A cross-sectional, observational study was carried out with 61 patients with microcephaly/CZS born between June 2015 and September 2017 (29 boys and 32 girls, average age of 22.8 months) and a control group with 58 non-CZS children born in the same period (25 boys and 33 girls, average age of 23.8 months). The functional clinical analysis considered the labial and lingual frena, tongue anterior projection, oral escape, palate form, and first tooth eruption. For the craniofacial analysis, facial anthropometric points and the cephalic perimeter at the time were measured. Demographic data were collected from medical records, and a clinical exam was performed in order to register the intrabuccal characteristics and craniofacial measures. The chi-square test and Student's t-test were used with a significance level of 0.05. RESULTS: The narrow palate form, tongue anterior projection, oral escape, and late first tooth eruption were significantly more present in the group with microcephaly/CZS. As for the craniofacial analysis, face width (Bi-Zi), mandible width (Go-Go), height of face upper third (Tr-G), and monthly growth of cephalic perimeter were significantly smaller, whereas height of face lower third (Sn-Gn) was significantly bigger in the group with microcephaly/CZS (P < 0.05). CONCLUSION: Children with microcephaly resulting from a congenital Zika infection showed functional, oral, and maxillofacial changes and smaller facial development in comparison with non-CZS children in the same age group.

How is orthodontic treatment need associated with perceived esthetic impact of malocclusion in adolescents?

INTRODUCTION: The purpose of this research was to evaluate the esthetic impact of orthodontic treatment need in adolescents. METHODS: This cross-sectional study was performed with 1172 adolescents aged 12 (n = 638) years and 15 (n = 534) years from Salvador, Bahia, Brazil. The esthetic impact was the following outcome variables: Aesthetic Component of the Index of Orthodontic Treatment Need and the Oral Aesthetic Subjective Impact Scale. The normative orthodontic treatment need was assessed by the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC) and by the Dental Aesthetic Index (DAI). Logistic regression models were adjusted, estimating crude odds ratio with the respective 95% confidence intervals. The variables with P ≤0.20 in the individual analyses were tested in multiple logistic regression models, remaining the variables with P ≤0.05. RESULTS: The results showed a statistically significant association for the esthetic impact (Aesthetic Component of the Index of Orthodontic Treatment Need and the Oral Aesthetic Subjective Impact Scale) when assessing the normative orthodontic treatment need by the DAI (P <0.05). However, there was no significant association between subjective esthetic impact and normative needs when using the IOTN-DHC (P >0.05). CONCLUSIONS: DAI was more associated with the adolescents' esthetic concern than IOTN-DHC and should be the Index of Orthodontic Treatment Need to be selected to complement the patient's self-perception.

Photobiomodulation for the treatment of periodontal pockets in patients with type 2 diabetes: 1-year results of a randomized clinical trial.

This study investigated the local effect of photobiomodulation (PBM) for the treatment of periodontal pockets in patients with periodontitis and type 2 diabetes. Thirty-eight periodontal pockets presenting probing depth (PD) and clinical attachment level (CAL) ≥ 5 mm were selected from 19 patients (two pockets/patient). The selected periodontal pockets were randomly assigned to receive mechanical debridement only (control group) or mechanical debridement with PBM (PBM group). Clinical measures, such as PD, CAL, bleeding on probing (BoP), and presence of supragingival biofilm (PI), were collected and compared at baseline, 3, 6, and 12 months. After 12 months, no statistically difference was observed for mean PD and mean CAL when control and PBM groups were compared. The frequency of pockets with PD 5-6 mm was significantly lower for the PBM group at 6 months when compared to the control group. Pockets with PD ≥ 7 mm changed significantly between baseline and 3, 6, and 12 months for the PBM group, while for the control group, statistical significance was only observed between baseline and 6 months. The PBM protocol used in this study did not provide significant changes for PD and CAL in periodontal pockets when compared to mechanical therapy only. However, PBM was more effective in reducing the percentage of moderate periodontal pockets at 6 months in patients with type 2 DM.

Do electrical current and laser therapies improve bone remodeling during an orthodontic treatment with corticotomy?

OBJECTIVES: Evaluate the bone remodeling during orthodontic movement with corticotomy when submitted to low-intensity electrical stimulation application (microcurrent-MC) and low-level laser therapy (LLLT). MATERIAL AND METHODS: One hundred and fifty Wistar rats were divided into the following 5 groups: (C) submitted to tooth movement; (Cort) tooth movement/corticotomy; (Cort-L) tooth movement/corticotomy/laser AsGaAl 808 nm (4.96J/50s); (Cort-Mc) tooth movement/corticotomy/microcurrent (10 µA/5 min); (Cort-L-Mc) tooth movement/corticotomy and laser/microcurrent alternated. Inflammation, angiogenesis, and osteogenesis were evaluated in the periodontal ligament (PDL) and alveolar bone on the 7th, 14th, and 21st days of orthodontic movement. RESULTS: The quantification of inflammatory infiltrate, angiogenesis and expression of TGF-ß1, VEGF, and collagen type I were favorably modulated by the application of therapies such as low-level laser therapy (LLLT), MC, or both combined. However, electrical stimulation increased fibroblasts, osteoclasts and RANK numbers, birefringent collagen fiber organization, and BMP-7 and IL-6 expression. CONCLUSIONS: Low-level laser therapy (LLLT) and MC application both improved the process of bone remodeling during orthodontic treatment with corticotomy. Still, electrical current therapy promoted a more effective tooth displacement but presented expected root resorption similar to all experimental treatments. CLINICAL RELEVANCE: It is important to know the effects of minimally invasive therapies on cellular and molecular elements involved in the bone remodeling of orthodontic treatment associated with corticotomy surgery, in order to reduce the adverse effects in the use of this technique and to establish a safer clinical routine.

Electrical stimulation enhances tissue reorganization during orthodontic tooth movement in rats.

OBJECTIVE: This study evaluated the effects of a low-intensity electric current on tissue reorganization during experimental orthodontic tooth movement. MATERIALS AND METHODS: Thirty-two animals were divided into two groups evaluated on days 3 and 7: OTM-orthodontic tooth movement and OTM + MC-orthodontic tooth movement and microcurrent application (10 µA/5 min). The samples were processed for histological, morphometric, and Western blotting analysis. RESULTS: Analysis of the periodontal ligament (PL) showed a significantly smaller number of granulocytes in the OTM + MC group on day 7.The number of fibroblasts was significantly higher in the OTM + MC group on days 3 and 7. The area of birefringent collagen fibers was more organized in the OTM + MC group on days 3 and 7. The number of blood vessels was significantly higher in the OTM + MC group on day 7. Microcurrent application significantly increased the number of osteoclasts in the compression region of the PL. In the OTM + MC group on day 7 of tooth movement, the expression of TGF-ß1 and VEGF was significantly reduced whereas the expression of bFGF was increased in PL. CONCLUSIONS: Electrical stimulation enhances tissue responses, reducing the number of granulocytes and increasing the number of fibroblasts, blood vessels, and osteoclasts and modulates the expression of TGF-ß1, VEFG, and bFGF. CLINICAL RELEVANCE: This technique is used in many areas of medicine, but poorly explored in dentistry and orthodontics. This treatment is cheap and non-invasive and can be applied by own orthodontist, and it can improve the treatment with a faster and safe tooth movement, without pain.

Connective tissue graft associated or not with low laser therapy to treat gingival recession: randomized clinical trial.

BACKGROUND: To evaluate the treatment of gingival recession with a connective tissue graft (CTG) alone or in combination with low-level laser therapy (CTG + L). METHODS: Forty patients presenting 40 Miller Class I and II gingival recessions were included. The defects were randomly assigned to receive either CTG (n = 20) or CTG + L (n = 20). A diode laser (660 nm) was applied to the test sites immediately after surgery and every other day for 7 days (eight applications). RESULTS: The mean percentage of root coverage was 91.9% for the test group and 89.48% for the control group after 6 months (p > 0.05). The test group presented more complete root coverage (n = 13, 65%) than the control group (n = 7, 35%) (p = 0.04). Dentine sensitivity decreased significantly after 6 months in both groups (p < 0.001). The two groups showed improvement in aesthetics at the end of treatment. CONCLUSIONS: Low-level laser therapy may increase the percentage of complete root coverage when associated with CTG.

Cardiovascular health status and metabolic syndrome in Ecuadorian natives/Mestizos aged 40 years or more with and without stroke and ischemic heart disease--an atahualpa project case-control nested study.

BACKGROUND: Knowledge of regional-specific cardiovascular risk factors is mandatory to reduce the growing burden of stroke and ischemic heart disease in Latin American populations. We conducted a population-based case-control study to assess which risk factors are associated with the occurrence of vascular events in natives/mestizos living in rural coastal Ecuador. METHODS: We assessed the cardiovascular health (CVH) status and the presence of the metabolic syndrome in all Atahualpa residents aged 40 years or more with stroke and ischemic heart disease and in randomly selected healthy persons to evaluate differences in the prevalence of such risk factors between patients and controls. RESULTS: A total of 120 persons (24 with stroke or ischemic heart disease and 96 matched controls) were included. A poor CVH status (according to the American Heart Association) was found in 87.5% case-patients and 81.3% controls (P = .464). The metabolic syndrome was present in the same proportion (58.3%) of case-patients and controls. Likewise, both sets of risk factors (poor CVH status and the metabolic syndrome) were equally prevalent among both groups (58.3% versus 49%, P = .501). CONCLUSIONS: This case-control study suggests that none of the measured risk factors is associated with the occurrence of vascular events. It is possible that some yet unmeasured risk factors or an unknown genetic predisposition may account for a sizable proportion of stroke and ischemic heart disease occurring in the native/mestizo population of rural coastal Ecuador.

Antimicrobial effect of Melaleuca alternifolia dental gel in orthodontic patients.

The aim of this study was to evaluate the antimicrobial effect and sensorial analysis of the gel developed with the essential oil of Melaleuca alternifolia. Thirty-four volunteers, divided into 2 groups, were monitored for 4 weeks. Initially, clinical biofilm (plaque index) and saliva samples (bacteria count) were collected, from which the standard values for each patient were obtained. For 7 days, group 1 used the melaleuca gel (Petite Marie/All Chemistry, São Paulo, Brazil), and group 2 used Colgate Total (S.B. Campo, São Paulo, Brazil). After 7 days, the plaque index was performed again, as well as the bacteria count and the sensorial analysis (appearance, color, odor, brightness, viscosity, and first taste sensation). The volunteers were instructed to return to their usual dental hygiene habits for 15 days. After this, group 1 started using Colgate Total, and group 2 started using the melaleuca gel, with the same evaluation procedures as the first week. The data were analyzed statistically with a significance level of 5%. In the bacteria count and clinical disclosure, the melaleuca gel was more effective in decreasing the dental biofilm and the numbers of bacteria colonies. According to the data from the sensory evaluation, Colgate Total (the control) showed better results regarding flavor and first sensation (P <0.05). We concluded that melaleuca gel is efficient in bacteria control but needs improvement in taste and first sensation.

Electrical stimulation therapy and rotary jet-spinning scaffold to treat bone defects.

The combination of electrical stimulation (ES) and bone tissue engineering (BTE) has been successful in treatments of bone regeneration. This study evaluated the effects of ES combined with PCL + ß-TCP 5% scaffolds obtained by rotary jet spinning (RJS) in the regeneration of bone defects in the calvaria of Wistar rats. We used 120 animals with induced bone defects divided into 4 groups (n = 30): (C) without treatment; (S) with PCL+ ß-TCP 5% scaffold; (ES) treated with ES (10 µA/5 min); (ES + S) with PCL + ß-TCP 5% scaffold. The ES occurred twice a week during the entire experimental period. Cell viability (in vitro: Days 3 and 7) and histomorphometric, histochemical, and immunohistochemical (in vivo; Days 30, 60, and 90) analysis were performed. In vitro, ES + S increased cell viability after Day 7 of incubation. In vivo, it was observed modulation of inflammatory cells in ES therapy, which also promoted blood vessels proliferation, and increase of collagen. Moreover, ES therapy played a role in osteogenesis by decreasing ligand kappa B nuclear factor-TNFSF11 (RANKL), increasing alkaline phosphatase (ALP), and decreasing the tartarate-resistant acid phosphatase. The combination of ES with RJS scaffolds may be a promising strategy for bone defects regeneration, since the therapy controlled inflammation, favored blood vessels proliferation, and osteogenesis, which are important processes in bone remodeling.

Can text messages encourage flossing among orthodontic patients?

OBJECTIVES: To assess the extent to which text messages on WhatsApp play a role in patient awareness of the importance of proper oral hygiene and flossing on a daily basis and to test the null hypothesis that daily text messages do not influence the flossing habits of orthodontics patients. MATERIALS AND METHODS: Forty-four patients wearing fixed orthodontic appliances with a mean age of 14.3 years participated in the study. Patients (male and female) were randomly assigned to two groups (n = 22): group 1, text messages sent via WhatsApp daily during the study period, and group 2 (control), no text messages received. Plaque index, gingival bleeding index, and halitosis were assessed at baseline and after 30 days. The results were analyzed and subjected to normality test, McNemar test, Fisher exact test, Mann-Whitney test, and Wilcoxon signed-rank test. RESULTS: There was a significant influence on flossing habits (P < .05) and a significant reduction in plaque and gingival bleeding indices in group 1 (P < .05). Group 1 had a significant reduction in halitosis (P < .05). CONCLUSIONS: Daily text messages seem to influence patient awareness of the importance of proper oral hygiene and flossing. The null hypothesis was rejected because those patients who received text messages every day changed their flossing habits.

Gestational protein restriction alters the RANKL/OPG system in the dental germ of offsprings.

Evaluate the dentinogenesis in the offspring of rats submitted to gestational protein restriction (GPR). DESIGN: The offspring were evaluated at the 21st day of gestation (21 dG). Assessments were made of morphological parameters and the RANKL/OPG system - bone tissue maturation markers - in the upper incisor tooth germ. Pregnant 10-week-old female Wistar rats were divided into normal protein (NP, 17% casein, n = 5) and low protein (LP, 6% casein, n = 5) diet groups. At 21 dG, the offspring maxillae were collected for histomorphometric and immunohistochemical analyses. RESULTS: The LP group showed decreased thickness of the dentin and odontoblast cell layers on the tooth germ. GPR led to decreased OPG expression and increased RANKL expression in the incisor germ. CONCLUSION: The results suggested that gestational protein restriction altered odontoblast RANKL/OPG expression and decreased dentin matrix deposition and thickness in tooth development.

Effect of two corticotomy protocols on periodontal tissue and orthodontic movement.

Objective To compare two corticotomy surgical protocols in rats to verify whether they alter conventional orthodontic movement. Methodology Sixty Wistar rats were divided into three groups - orthodontic movement (CG), orthodontic movement and corticotomy (G1) and orthodontic movement with corticotomy and decortication (G2) - and euthanized after 7 and 14 days. Tooth movement (mm), bone volume fraction and bone volume ratio to total volume (BV/TV), and bone mineral density (BMD) were evaluated by micro-CT. The total amount of bone was measured in square millimeters and expressed as the percentage of bone area in the histomorphometry. The number of positive TRAP cells and RANK/RANKL/OPG interaction were also investigated. Results Day 14 showed a statistically significant difference in orthodontic tooth movement in CG compared with G1 (7.52 mm; p=0.009) and G2 (7.36 mm; p=0.016). A micro-CT analysis revealed a difference between CG, G1 and G2 regarding BV/TV, with G1 and G2 presenting a lower BV/TV ratio at 14 days (0.77 and 0.73 respectively); we found no statistically significant differences regarding BMD. There was a difference in the total amount of bone in the CG group between 7 and 14 days. At 14 days, CG presented a significantly higher bone percentage than G1 and G2. Regarding TRAP, G2 had more positive cells at 7 and 14 days compared with CG and G1. Conclusion Corticotomy accelerates orthodontic movement. Decortication does not improve corticotomy efficiency.

Macroscopic and radiographic aspects of orthodontic movement associated with corticotomy: animal study.

INTRODUCTION: To quantify the rate of tooth movement in two corticotomy protocols in an experimental model in rats through macroscopic and radiographic analysis. METHODS: The animals were divided into three groups: orthodontic movement (CO), orthodontic movement plus corticotomy surgery (G2), and orthodontic movement and corticotomy surgery with decorticalization (G3).The euthanasia occurred in 7 and 14 days. The data were statistically analyzed (p < 0.05). RESULTS: The CO presented lower distance between the mesial surface of the first molar and the distal surface of the third molar when compared to the G2 (6.96 ± 0.24, p = 0.009) and G3 (6.93 ± 0.18, p = 0.016) in the macroscopic analysis. In the 7 days, there was no statistically significant radiographic difference between the three groups: CO(0.94 ± 0.21 mm2), G2(1.05 ± 0,27 mm2), and G3(1.08 ± 0.27 mm2).There was a statistically significant difference between CO (0.87 ± 0.12 mm2), G2 (1.00 ± 0.12 mm2), and G3 (1.11 ± 0.14 mm2) at 14 days. There was a statistically significant linear difference between the groups in all periods. CONCLUSION: Tooth movement and the region of interest were influenced by corticotomy, regardless of the surgical technique in the 14 days.

Electrical stimulation: Complementary therapy to improve the performance of grafts in bone defects?

The limitations of bone reconstruction techniques have stimulated the tissue engineering for the repair of large bone defects using osteoconductive materials and osteoinductive agents. This study evaluated the effects of low intensity electric current on the inorganic bovine graft in calvaria defects. Bone defects were performed with piezoelectric system in the calvaria of Wistar rats divided into four groups (n = 24): (C) without grafting and without electrical stimulation; (E) with grafting; (MC) without grafting and submitted to electrical stimulation; (MC + E) with grafting and submitted to electrical stimulation. Inflammatory, angiogenic and osteogenic events during bone repair at the 10th, 30th, 60th, and 90th days were considered. Several inflammatory markers demonstrated the efficacy of grafting in reducing inflammation, particularly when subjected to electrical stimulation. Angiogenesis and collagen organization were more evident by electrical stimulation application on the grafts. Moreover, the osteogenic cell differentiation process indicated that the application of microcurrent on grafting modulated the homeostasis of bone remodeling. It is concluded that microcurrent favored the performance of grafts in calvarial rat model. Low-intensity electrical current might improve the osteoconductive property of grafting in bone defects. Therefore, electrical current becomes an option as complementary therapy in clinical trials involving bone surgeries and injuries. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 924-932, 2019.

Periodontal response to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease.

BACKGROUND: Systemic conditions can influence orthodontic tooth movement. This study evaluates histologic periodontal responses to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease. METHODS: Forty Wistar rats were divided according their systemic condition (SC) into diabetic (D) and non-diabetic (ND) groups. Each group was subdivided into control (C), orthodontic tooth movement (OM), ligature-induced periodontitis (P) and ligature-induced periodontitis with orthodontic movement (P+OM) groups. Diabetes mellitus (DM) was induced with alloxan monohydrate, and after 30 days, the P group received a cotton ligature around their first lower molar crown. An orthodontic device was placed in OM and P+OM groups for 7 days, and the animals were then euthanized. RESULTS: Differences in OM between D and ND groups were not significant (6.87± 3.55 mm and 6.81 ± 3.28 mm, respectively), but intragroup analysis revealed statistically significant differences between the P+OM groups for both SCs. Bone loss was greater in the D group (0.16 ± 0.07 mm2 ) than in the ND group (0.10 ± 0.03 mm2 ). In intragroup analysis of the D condition, the P+OM group differed statistically from the other groups, while in the ND condition, the P+OM group was different from the C and OM groups. There was a statistically significant difference in bone density between D and ND conditions (18.03 ± 8.09% and 22.53 ± 7.72%) in the C, P, and P+OM groups. CONCLUSION: DM has deleterious effects on bone density and bone loss in the furcation region. These effects are maximized when associated with ligature-induced periodontitis with orthodontic movement.

Evaluation of the local effect of nonsurgical periodontal treatment with and without systemic antibiotic and photodynamic therapy in generalized aggressive periodontitis. A randomized clinical trial.

BACKGROUND: This study's aim was to evaluate the local effect of clarithromycin associated with antimicrobial photodynamic therapy (aPDT) in the treatment of generalized aggressive periodontitis. MATERIALS AND METHODS: The study sample comprised 72 periodontal pockets on single-rooted teeth in multiple quadrants, with both probing depth and clinical attachment level ≥5 mm, and with bleeding on probing. The pockets were randomly distributed into four groups (n = 18 each) that received ultrasonic periodontal debridement in addition to placebo (the UPD group), systemic clarithromycin (the UPD + CLM group), aPDT (the UPD + aPDT group), or both systemic clarithromycin and aPDT (the UPD + CLM + aPDT group). The measurements were performed prior to treatment (baseline) and at 3 and 6 months postoperatively. The following parameters were evaluated: plaque index, bleeding on probing, probing depth, gingival recession, and clinical attachment level. A 5% significance level was used in the statistical analysis. RESULTS: At 3 months, UPD + aPDT, UPD + CLM, and UPD + CLM + aPDT groups all exhibited reduced probing depths relative to the UPD group (p < 0.05). However, at 6 months, the reduction in mean probing depth was greater in the antibiotic groups (UPD+CLM and UPD+CLM+aPDT) than in the UPD and UPD+aPDT groups (p < 0.05). Regarding clinical attachment level, only the UPD+CLM+aPDT group presented a significant gain relative to the UPD and UPD + PDT groups (p < 0.05). CONCLUSIONS: Ultrasonic periodontal debridement has greater clinical advantages when associated with clarithromycin than with associated with aPDT. However, the joint application of aPDT and clarithromycin did not present additional benefits.

Initial pulp changes during orthodontic movement: histomorphological evaluation.

This study evaluated pulp changes in molars of rats submitted to tooth movement by application of a 0.4 N force. Twenty-five adult male Wistar rats (Rattus norvegicus, albinus) were randomly assigned to 5 groups (n=5), being one control group not submitted to force application, and four study groups of 6, 12, 24 and 72 h of force application. The study groups received a 5-mm long nickel-titanium closed coil spring, placed from the right maxillary first molar to the maxillary incisors of each animal. The coil spring was used for mesial inclination of the first molar. After the specific period of tooth movement of each study group, the animals were sacrificed and specimens containing the teeth submitted to movement were processed and stained with hematoxylin and eosin for histological analysis under light microscopy. The results demonstrated alteration of the odontoblastic layer, with hypertrophy of odontoblasts especially at the mesial area of the coronal pulp, edema of the pulp connective tissue in the central area of the pulp, and vascular alteration with accumulation of erythrocytes and leukocytes inside the vessels, especially at the mesial root of the moved teeth. These changes were less remarkable for the 72-h period. Thus, it may be concluded that tooth movement yielded pulpal tissue alterations compatible with an inflammatory process, which are reversible if the aggression is not more intense than the physiological limit of tissue tolerance.

Epidemiology of posterior crossbite in the primary dentition.

This epidemiological survey was conducted on 2,016 children from 8 private and 12 public preschools at the city of Bauru, São Paulo, Brazil. The sample was composed of 1,032 males and 984 females in the primary dentition stage, aged 3 to 6 years. Normal occlusion was observed in 26.74% of the sample; thus, 73.26% of children presented some type of malocclusion. Among the malocclusions, the following transverse problems were diagnosed: unilateral posterior crossbite (11.65%), anterior open bite associated with posterior crossbite (6.99%), bilateral posterior crossbite (1.19%), unilateral posterior crossbite associate with anterior crossbite (0.79%) and full crossbite (0.19%) totalizing 20.81% of the transverse problems. Mandibular functional deviation was observed in 91.91% of children with unilateral posterior crossbite, characterizing the functional unilateral posterior crossbite. The results demonstrated that the prevalence of posterior crossbite was compatible with previous data in the literature, with predominance of functional unilateral posterior crossbite.

Debonding forces of different pads in a lingual bracket system.

OBJECTIVE:: To evaluate the shear bond strength of lingual orthodontic brackets with resin or metal pads, the location of bond failure and the adhesive remnant index (ARI). METHODS:: A total of 40 extracted upper premolars were randomly divided into two groups of 20 each: bonding with brackets having (1) pads with extended resin directly on the lingual surface of teeth, and (2) pads with metal custom base on the lingual surface of teeth. The debonding force was measured with an Instron universal testing machine. A Student's t-test was used to assess the difference between groups (α = 0.05). RESULTS:: The results showed a significant difference between the groups (p < 0.001). The shear bond strength of metal pads was significantly higher than resin pads. CONCLUSIONS:: Within the limitations of this in vitro study, it was concluded that the bond strength of lingual brackets with metal pads was higher than that of brackets with composite resin pads, due to the metal part being a single unit and welded. The failure location in the region between the bracket and the resin pad affected a higher percentage of the resin pads than the metal pads.