Mírian Aiko Nakane Matsumoto

Muscular, functional and orthodontic changes in pre school children with enlarged adenoids and tonsils

INTRODUCTION Hypertrophy of the adenoids and palatine tonsils is the second most frequent cause of upper respiratory obstruction and, consequently, mouth breathing in children. Prolonged mouth breathing leads to muscular and postural alterations which, in turn, cause dentoskeletal changes. OBJECTIVE The aim of this study was to determine muscular, functional and dentoskeletal alterations in children aged 3-6 years. MATERIALS AND METHODS Seventy-three children, including 44 with tonsil hypertrophy and 29 controls, were submitted to otorhinolaryngologic, speech pathologic and orthodontic assessment. RESULTS Otorhinolaryngologic evaluation revealed a higher incidence of nasal obstruction, snoring, mouth breathing, apneas, nocturnal hypersalivation, itchy nose, repeated tonsillitis and bruxism in children with tonsils hypertrophy. Speech pathologic assessment showed a higher incidence of open lip and lower tongue position, and of hypotonia of the upper and lower lips, tongue and buccinator muscle in these children, accompanied by important impairment in mastication and deglutition. Orthodontic evaluation demonstrated a higher incidence of lower mandible position in relation to the cranial base, a reduction in lower posterior facial height, transverse atresia of the palate, and a dolicofacial pattern. CONCLUSION Postural and functional alterations anticipate dentoskeletal changes, except for the facial pattern. Postural alterations and the skeletal pattern seem to play an important role in infant dentofacial growth.

Influência do padrão respiratório na morfologia craniofacial

OBJETIVO: este estudo teve como objetivo avaliar por meio de analise cefalometrica as diferencas nas proporcoes faciais de criancas respiradoras bucais e nasais. FORMA DE ESTUDO: coorte transversal. MATERIAL E METODO: Foram selecionadas 60 criancas entre 6 e 10 anos que, apos avaliacao otorrinolaringologica para o diagnostico do tipo de respiracao, foram divididas em dois grupos: grupo I, constituido de criancas respiradoras bucais, com elevado grau de obstrucao das vias aereas e grupo II, composto de criancas respiradoras nasais. Os pacientes foram submetidos a avaliacao ortodontica por meio de radiografias cefalometricas em norma lateral, a fim de avaliar as proporcoes faciais, atraves das seguintes medidas cefalometricas: SN.GoGn, ArGo.GoMe, N-Me, N-ENA, ENA-Me, S-Go, S-Ar, Ar-Go; e os seguintes indices: iAF=S-Go / N-Me, iAFA=ENA-Me / N-Me e iPFA=N-ENA / ENA-Me. RESULTADO: Foi constatada que a inclinacao do plano mandibular (SN.GoGn) nos pacientes respiradores bucais foi estatisticamente maior que nos respiradores nasais, enquanto que a proporcao da altura facial posterior e anterior (iAF), e da altura facial anterior superior e inferior (iPFA) foram estatisticamente menores nos pacientes bucais, indicando altura facial posterior menor que a anterior e altura facial anterior inferior aumentada nesses pacientes. CONCLUSAO: Pode-se concluir, entao, que os respiradores bucais tendem a apresentar maior inclinacao mandibular e padrao de crescimento vertical, evidenciando a influencia da funcao respiratoria no desenvolvimento craniofacial.

Dentofacial morphology of mouth breathing children

The relationship between dentofacial morphology and respiration has been debated and investigated from various approaches. The aim of this study was to verify the skeletal and dental relationship of mouth and nose breathing children. Thirty-five children, 7 to 10 years of age, were submitted to orthodontic and otorhinolaryngologic evaluations and were separated into 2 groups: 15 nose breathers and 20 mouth breathers. Each subject underwent a cephalometric radiograph analysis. Statistical analysis (Mann-Whitney U test) indicated that changed mode of breathing was associated with 1) maxillo-mandibular retrusion in relation to the cranial base in the mouth breathers; 2) the SNGoGn and NSGn angles were greater in the mouth breathing group; 3) incisor inclination in both jaws and the interincisal angle were not different between groups. There was no statistically significant difference in the maxillary and mandibular molar heights between the nose breathers and mouth breathers.

Breathing mode influence in craniofacial development

AIM The aim of this study was to evaluate the differences in facial proportions of nose and mouth breathing children using cephalometric analysis. STUDY DESIGN Transversal cohort. MATERIAL AND METHOD Sixty cephalometric radiographs from pediatric patients aged 6 to 10 years were used. After otorhinolaryngological evaluation, patients were divided into two groups: Group I, with mouth breathing children and group II, with nose breathers. Standard lateral cephalometric radiographs were obtained to evaluate facial proportions using the following measures: SN.GoGn, ArGo.GoMe, N-Me, N-ANS, ANS-Me and S-Go; and the following indexes: PFH-AFH ratio: S-Go/N-Me; LFH-AFH ratio: ANS-Me/N-Me and UFH-LFH ratio: N-ANS/ANS-Me. RESULTS It was observed that the measurements for the inclination of the mandibular plane (SN.GoGn) in mouth breathing children were statistically higher than those in nasal breathing children. The posterior facial height was statistically smaller than the anterior one in mouth breathing children (PFH-AFH ratio). Thus, the upper anterior facial height was statistically smaller than the lower facial height (UFH-LFH ratio). CONCLUSION We concluded that mouth breathing children tend to have higher mandibular inclination and more vertical growth. These findings support the influence of the breathing mode in craniofacial development.

In-vivo evaluation of the contamination of Super Slick elastomeric rings by Streptococcus mutans in orthodontic patients

INTRODUCTION We investigated in vivo the contamination by Streptococcus mutans of Super Slick elastomeric rings (TP Orthodontics, LaPorte, Ind), manufactured with Metafasix technology (TP Orthodontics), using microbial culture and scanning electron microscopy (SEM). METHODS Twenty patients undergoing fixed orthodontic appliance therapy were selected. Super Slick elastomeric rings (n = 160) were tied to brackets on the right maxillary premolars or molars and left mandibular premolars or molars. Conventional elastomeric rings (n = 160) were tied to brackets on the contralateral premolars or molars with the same split-mouth design. After a 15-day intraoral period, 75 elastomeric rings of each type were retrieved, submitted to microbiologic processing, and cultured in bacitracin sucrose broth-selective enrichment broth culture media. The number of S mutans colonies or biofilms on the surface of the electrometric rings was counted by using a stereomicroscope. Data were analyzed statistically with the Wilcoxon nonparametric test at the 5% significance level. Four representative rings of each type were chosen for SEM analysis. RESULTS Statistical analysis by the Wilcoxon nonparametric test showed that the Super Slick elastomeric rings had statistically significant greater S mutans contamination than the conventional elastomeric rings (P <.0001). No formation of S mutans colonies or biofilms was observed in the elastomeric rings removed directly from their original packages. SEM micrographs showed fissures on the surface of Super Slick elastomeric rings. No fissures were found on conventional elastomeric rings. When the microbiologic culture was positive, S mutans bacterial biofilm was observed on both types of ligatures. CONCLUSIONS There was no clinical evidence that Super Slick elastomeric rings are effective in reducing bacterial biofilm formation on their surfaces, and a recommendation for their use in orthodontic therapy for that purpose is not justifiable.

Does rapid maxillary expansion increase nasopharyngeal space and improve nasal airway resistance

OBJECTIVE To evaluate the effect of rapid maxillary expansion (RME) on the dimension of the nasopharyngeal space and its relation to nasal airway resistance. METHODS Twenty-five school-age children (from 7 to 10 year-old) with mouth and/or mixed breathing, with mixed dentition and uni- or bilateral posterior crossbite involving the deciduous canines and the first permanent molars, were evaluated. RME was placed and remained during 90 days. Rhinomanometry and orthodontic documentation were performed at four different times, i.e., before (T(1)), immediately after (T(2)), 90 days (T(3)) and 30 months (T(4)) after RME. RESULTS Differences in nasopharyngeal area and in nasal airway resistance were observed only 30 months after RME, and could be explained by facial growth, and not because of the orthodontic procedure. CONCLUSION RME does not influence on nasopharyngeal area or nasal airway resistance in long-term evaluation.

Long-term effects of rapid maxillary expansion on nasal area and nasal airway resistance

Background Rapid maxillary expansion (RME) may improve the nasal respiratory pattern. This study was performed to evaluate the effect of RME on the nasal cavity by acoustic rhinometry and computed rhinomanometry and to determine nasal and maxillary width by posteroanterior cephalometric radiography, up to 30 months after the orthodontic procedure. Methods Twenty-seven children with oral breathing, ranging in age from 7 to 10 years, and with mixed dentition were selected. The children had unior bilateral posterior crossbite involving deciduous canines and the first permanent molars. All subjects were submitted to nasofibroscopy, acoustic rhinometry, and computed rhinomanometry and posteroanterior cephalometric radiography at four different times, i.e., before expansion, immediately, 90 days and 30 months after expansion. Results The mean linear left-to-right nasal cavity lateral prominence and left-to-right jugal points cephalometric measures increased considerably after expansion and this increase was maintained throughout the period of evaluation. There was an immediate significant decrease in nasal resistance, up to 90 days after RME, but the nasal resistance increased 30 months after the procedure. The acoustic rhinometry results did not show any difference in values throughout time. Conclusion RME significantly increased nasal and maxillary width as measured by frontal cephalometry, but the nasal mucosal effects were more subtle. Also, the influence of RME on nasal resistance was not stable, and nasal resistance values returned to close to the initial ones after 30 months.

Anticariogenic effect of fluoride-releasing elastomers in orthodontic patients

This in vivo experimental study evaluated the efficacy of fluoride-releasing elastomers in the control of Streptococcus mutans levels in the oral cavity. Forty orthodontic patients were recruited and divided into two groups of 20. Fluoride-releasing elastomeric ligature ties (Fluor-I-Ties, Ortho Arch Co. Inc., USA) were used in the experimental group, and conventional elastomeric ligature ties (D. Morelli, Brazil), in the control group. Two initial samples of saliva were collected at a 14-day interval to determine the number of colony forming units (CFU) of Streptococcus mutans. Immediately after collecting the second sample, fluoride-releasing elastomeric ligature ties were placed in the patients of the experimental group, and conventional ligature ties, in the patients of the control group. Seven, 14 and 28 days after placement of the elastomeric ligature ties, saliva and plaque surrounding the orthodontic appliance were collected for microbiologic analysis. There were no significant differences in the number of Streptococcus mutans CFUs in saliva or plaque in the area surrounding the fluoride-releasing or conventional elastomeric ligature ties. Thus, fluoride-releasing elastomeric ligature ties should not be indicated to reduce the incidence of enamel decalcification in orthodontic patients. Since there was no significant reduction in S. mutans in saliva or plaque, other means of prevention against enamel decalcification should be indicated for these patients.

Use of the checkerboard DNA–DNA hybridisation technique for in vivo detection of cariogenic microorganisms on metallic brackets, with or without use of an antimicrobial agent

OBJECTIVE Using checkerboard DNA-DNA hybridisation (CDDH) assay, this randomised clinical study evaluated the contamination of metallic brackets by four cariogenic bacterial strains (Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei and Lactobacillus acidophilus) and the efficacy of 0.12% chlorhexidine gluconate (CHX) mouthwashes in reducing bacterial contamination. METHODS Thirty-nine 11-33-year-old patients under treatment with fixed orthodontic appliances were enrolled in the study and had 2 new metallic brackets bonded to premolars. Nineteen patients used a 0.12% CHX mouthwash (Periogard) and 20 patients used a placebo mouthwash (control) twice a week. After 30 days, the brackets were removed and samples were obtained for analysis by CDDH. Data were analysed statistically by the Kruskal-Wallis test (α=0.05) using the SAS software. RESULTS S. mutans, S. sobrinus, L. casei and L. acidophilus were detected in 100% of the samples from both groups. However, brackets of the control group were more heavily contaminated by S. mutans and S. sobrinus (P<0.01). In the experimental group, although all counts decreased after rinsing with the chlorhexidine solution, there was significant difference only for S. mutans (P=0.03). CONCLUSIONS The use of 0.12% chlorhexidine gluconate mouthwashes can be useful in clinical practice to reduce the levels of cariogenic microorganisms in patients under treatment with fixed orthodontic appliances.

Streptococcus mutans counts in plaque adjacent to orthodontic brackets bonded with resin-modified glass ionomer cement or resin-based composite

This study investigated the number of Streptococcus mutans CFU (colony forming units) in the saliva and plaque adjacent to orthodontic brackets bonded with a glass ionomer cement--GIC (Fuji Ortho) or a resin-based composite--RC (Concise). Twenty male and female patients, aged 12 to 20 years, participated in the study. Saliva was collected before and after placement of appliances. Plaque was collected from areas adjacent to brackets and saliva was again collected on the 15th, 30th, and 45th day after placement. On the 30th day, 0.4% stannous fluoride gel was applied for 4 minutes. No significant modification in the number of Streptococcus mutans CFU in saliva was observed after placement of the fixed orthodontic appliances. On the 15th day, the percentage of Streptococcus mutans CFU in plaque was statistically lower in sites adjacent to GIC-bonded brackets (mean = 0.365) than in those adjacent to RC-bonded brackets (mean = 0.935). No evidence was found of a contribution of GIC to the reduction of CFU in plaque after the 15th day. Topical application of stannous fluoride gel on the 30th day reduced the number of CFU in saliva, but not in plaque. This study suggests that the antimicrobial activity of GIC occurs only in the initial phase and is not responsible for a long-term anticariogenic property.