Post-orthodontic cephalometric variations in bimaxillary protrusion cases managed by premolar extraction - A retrospective study.

BACKGROUND: Bimaxillary protrusion is a common dentofacial condition associated with proclination of maxillary and mandibular incisors in relation to the dental and cranial bases resulting in soft tissue procumbency. The present retrospective study aimed to investigate dental and soft tissue profile changes using cephalometric analysis to evaluate bimaxillary protrusion patients after extraction of the first four premolars and subsequent retraction of the anterior teeth. MATERIALS AND METHODS: Pre-treatment and post-treatment cephalometric radiographs of 46 Saudi patients (16 males and 30 females), 18-30 years of age with bimaxillary protrusion, were selected based on inclusion criteria. Dental and soft tissue landmarks were traced using the Dolphin® imaging software and statistically analyzed with SPSS® 21 software. RESULTS: The upper and lower incisors retroclined by a mean value of 9.6° and 9.65°, respectively, and an average distance of 4.1 mm. The level of maxillary incisor exposure was reduced by approximately 1.1 mm after treatment. A mean increase of 6.6° in the nasolabial angle was also observed. Multiple regression analysis showed that retraction of both upper and lower incisors by 1 mm would result in a 0.44 mm retraction of the upper and lower lips. CONCLUSION: A statistically significant increase in the nasolabial angle and upper lip length was found in relation to upper and lower incisor retraction and retroclination. A significant reduction was also evident in the post treatment upper incisor exposure, facial convexity angle and mentolabial sulcus depth.

Prevalence of caries and malocclusion in an indigenous population in Chiapas, Mexico.

OBJECTIVES: To assess the prevalence of caries and malocclusion in Mayan Mexican adolescents, 14-20 years of age, living in Chiapas, Mexico. METHODS: This was a cross-sectional, population-based, quantitative, epidemiological study. Sites were chosen to capture subjects representative of the state's Mayan population. A total of 354 subjects were recruited. Caries experience was quantified, via visual inspection, using the Decayed, Missing and Filled Surface (DMFS) index. Malocclusion was quantified using the Index of Complexity, Outcome and Need (ICON). RESULTS: Our data showed that 99% of the population had caries experience, with a median DMFS score of 8. Of the 99% with caries experience, over half had caries affecting more than five tooth surfaces. Thirty-seven per cent of the students had unmet orthodontic treatment need, and 46.46% presented a Class II, and 39.09% a Class III, anterior-posterior relationship. CONCLUSIONS: Less than 1% of the population had any exposure to orthodontics, demonstrating the lack of access to care. Likewise, only 1% of the population was found to have no caries experience, exhibiting a large unmet treatment need. The median DMFS score of 8 was also high in comparison with the median DMFS in the USA of 6. Our data suggest a correlation between the lack of access to care and high prevalence of caries and malocclusion in Mexican Mayans who inhabit Chiapas, Mexico.

Is sickle cell anemia a risk factor for severe dental malocclusion?

The aim of this study was to investigate possible associations between sickle cell anemia (SCA) and the severity of dental malocclusion (MO). This was a retrospective cohort study of 93 individuals with SCA (G1) and 186 individuals without the disease (G2). SCA patients were randomly selected by a simple draw from patients treated in the Centro de Hematologia e Hemoterapia do Maranhão (HEMOMAR) in northeastern Brazil. Patients aged between 16 and 60 were included after being tested for the hemoglobin S gene. G2 consisted of individuals living in the same residence as the patients. The Dental Aesthetic Index (DAI), as well as some morphological deviations not included in DAI, were used for the orthodontic evaluation of MO. Poisson regression with robust variance adjustment was employed to estimate relative risk (RR). In the multivariate analysis, SCA was associated with moderate (RR = 1.36) and very severe MO (RR = 8.0). SCA is correlated with anterior tooth loss (RR = 1.94), anterior spacing (RR = 1.66), overjet (RR = 1.87), anterior crossbite (RR = 1.94), and open bite (RR = 1.94). Thus, SCA is a risk factor for moderate and very severe MO.

Is sickle cell anemia a risk factor for severe dental malocclusion?

The aim of this study was to investigate possible associations between sickle cell anemia (SCA) and the severity of dental malocclusion (MO). This was a retrospective cohort study of 93 individuals with SCA (G1) and 186 individuals without the disease (G2). SCA patients were randomly selected by a simple draw from patients treated in the Centro de Hematologia e Hemoterapia do Maranhão (HEMOMAR) in northeastern Brazil. Patients aged between 16 and 60 were included after being tested for the hemoglobin S gene. G2 consisted of individuals living in the same residence as the patients. The Dental Aesthetic Index (DAI), as well as some morphological deviations not included in DAI, were used for the orthodontic evaluation of MO. Poisson regression with robust variance adjustment was employed to estimate relative risk (RR). In the multivariate analysis, SCA was associated with moderate (RR = 1.36) and very severe MO (RR = 8.0). SCA is correlated with anterior tooth loss (RR = 1.94), anterior spacing (RR = 1.66), overjet (RR = 1.87), anterior crossbite (RR = 1.94), and open bite (RR = 1.94). Thus, SCA is a risk factor for moderate and very severe MO.

The psychosocial impact of dental aesthetics questionnaire--translation and cross-cultural validation in Croatia.

PURPOSE: To perform a translation and validation of the psychosocial impact of dental aesthetics questionnaire (PIDAQ) in the Croatian cultural context. METHODS: A total of 262 subjects (34 % males) aged 18-30 years (mean age 22.7 ± 2.6) were included. The questionnaire included the PIDAQ, a self-assessment of satisfaction with dental aesthetics, a self-perceived dental treatment need assessment, self-reported malocclusion, an aesthetic component of index of orthodontic treatment need (IOTN AC) and an oral health impact profile (OHIP-14 CRO). The subjects' orthodontic treatment needs were assessed by a dentist using the dental health and aesthetic component of the IOTN. The internal consistency, test-retest reliability, validity and responsiveness were assessed. Little's Irregularity index was used to correlate the amount of resolution of dental crowding by orthodontic treatment with the change in PIDAQ domains. RESULTS: The domains of the Croatian version of the PIDAQ showed satisfactory internal consistency (α ranging from 0.79 to 0.95) and high test-retest reliability (r > 0.85). The significant association between the PIDAQ domains and self-reported satisfaction with teeth appearance, IOTN AC and OHIP-14 CRO (p < 0.001) confirmed the convergent validity. The domains were able to detect differences in the subjects' psychosocial impact related to orthodontic treatment that improved dental aesthetics in responsiveness testing (p < 0.001). CONCLUSION: The Croatian version of the PIDAQ demonstrated good psychometric properties, similar to those of the original.

Impact of malocclusion on quality of life among New Zealand adolescents.

OBJECTIVES: To determine whether malocclusion is associated with oral-health-related quality of life (OHRQoL) in New Zealand adolescents. METHODS: Data from two cross-sectional epidemiological studies of adolescents in Taranaki and Otago were used. Each participant completed a self-administered questionnaire and underwent a clinical examination. Information collected included sociodemographic characteristics (sex, ethnicity and household deprivation), and clinical measures (caries and malocclusion, the latter measured with the Dental Aesthetic Index, or DAI). OHRQoL was measured using the validated 16-item impact short-form Child Perceptions Questionnaire (CPQ11-14). Linear regression was used to model the CPQ11-14 score. RESULTS: 783 adolescents (52.6% male) took part. One-fifth had a handicapping malocclusion and one-third had a minor malocclusion or none. The overall mean DMFS was 2.3 (SD, 3.8), with slightly more than 50% being caries-free. With the exception of the oral symptoms domain, females presented with higher mean CPQ11-14 and domain scores, while Mãori had lower scores. There was a distinct gradient in mean CPQ11-14 and domain scores across the categories of malocclusion severity, whereby those in the 'handicapping' category of the DAI had the highest CPQ11-14 score. Linear regression modeling of the CPQ11-14 score showed that, after controlling for DMFS and socio-demographic characteristics, malocclusion category and being female were positively associated with higher CPQ11-14 scores. CONCLUSION: A severe malocclusion appears to have a negative impact on the OHRQoL of New Zealand adolescents.

Occlusal characteristics and orthodontic treatment need in black adolescents in Salvador/BA (Brazil): an epidemiologic study using the Dental Aesthetics Index.

OBJECTIVE: The objective of this article is to evaluate the need of orthodontic treatment, prevalence and severity of the malocclusions in individuals of black ethnicity in a representative sample of schoolchildren of the city of Salvador/Brazil, as well as to verify if the malocclusion was affected by socio-demographic conditions such as age and gender. METHODS: The reference population was constituted of schoolchildren with age between 12 and 15 years, enrolled in public and private schools. The malocclusion was evaluated in 486 students of black ethnicity, with ages varying from 12 to 15 years, selected in random sample in multiple stages. The adopted significance level was 1% and the power of the test was 90%. A questionnaire registering demographic characteristics was filled out by each individual. The Dental Aesthetics Index (DAI) was used by previously calibrated examiners (kappa 0.89), according to criteria of the World Health Organization. RESULTS: It was verified that most of the individuals (76%) had little or any need for orthodontic treatment. About 24% showed a condition of severe malocclusion, culminating in a vital need for orthodontic treatment. The main occlusal characteristics found in the group with high need of orthodontic treatment were dental crowding and accentuated overjet. The age was positively related to the improvement of the maxillary overjet and to the presence of crowding. CONCLUSION: The development of public politics that aim the insertion of orthodontic treatment among the procedures of health programs, with the implementation and development of specialized centers, is fundamental.

Prevalence of long face pattern in Brazilian individuals of different ethnic backgrounds.

OBJECTIVE: The long face pattern is a facial deformity with increased anterior total facial height due to vertical excess of the lower facial third. Individuals with long face may present different degrees of severity in vertical excess, as well as malocclusions that are difficult to manage. The categorization of vertical excess is useful to determine the treatment prognosis. This survey assessed the distribution of ethnically different individuals with vertical excess according to three levels of severity and determined the prevalence of long face pattern. MATERIAL AND METHODS: The survey was comprised of 5,020 individuals of Brazilian ethnicity (2,480 females and 2,540 males) enrolled in middle schools in Bauru-SP, Brazil. The criterion for inclusion of individuals with vertically impaired facial relationships was based on lip incompetence, evaluated under natural light, in standing natural head position with the lips at rest. Once identified, the individuals were classified into three subtypes according to the severity: mild, moderate, and severe. Then the pooled sample was distributed according to ethnical background as White (Caucasoid), Black (African descent), Brown (mixed descent), Yellow (Asian descent) and Brazilian Indian (Brazilian native descent). The Chi-square (χ²) test was used (p<0.05) to compare the frequency ratios of individuals with vertically impaired facial relationships in the total sample and among different ethnicities, according to the three levels of severity. RESULTS: The severe subtype was rare, except in Black individuals (7.32%), who also presented the highest relative frequency (45.53%) of moderate subtype, followed by Brown individuals (43.40%). In the mild subtype, Yellow (68.08%) and White individuals (62.21%) showed similar and higher relative frequency values. CONCLUSIONS: Black individuals had greater prevalence of long face pattern, followed by Brown, White and Yellow individuals. The prevalence of long face pattern was 14.06% in which 13.39% and 0.68% belonged to moderate and severe subtypes, respectively.

Prevalence of long face pattern in Brazilian individuals of different ethnic backgrounds

Objective: The long face pattern is a facial deformity with increased anterior total facial height due to vertical excess of the lower facial third. Individuals with long face may present different degrees of severity in vertical excess, as well as malocclusions that are difficult to manage. The categorization of vertical excess is useful to determine the treatment prognosis. This survey assessed the distribution of ethnically different individuals with vertical excess according to three levels of severity and determined the prevalence of long face pattern. Material and Methods: The survey was comprised of 5,020 individuals of Brazilian ethnicity (2,480 females and 2,540 males) enrolled in middle schools in Bauru-SP, Brazil. The criterion for inclusion of individuals with vertically impaired facial relationships was based on lip incompetence, evaluated under natural light, in standing natural head position with the lips at rest. Once identified, the individuals were classified into three subtypes according to the severity: mild, moderate, and severe. Then the pooled sample was distributed according to ethnical background as White (Caucasoid), Black (African descent), Brown (mixed descent), Yellow (Asian descent) and Brazilian Indian (Brazilian native descent). The Chi-square (χ 2 ) test was used (p<0.05) to compare the frequency ratios of individuals with vertically impaired facial relationships in the total sample and among different ethnicities, according to the three levels of severity. Results: The severe subtype was rare, except in Black individuals (7.32%), who also presented the highest relative frequency (45.53%) of moderate subtype, followed by Brown individuals (43.40%). In the mild subtype, Yellow (68.08%) and White individuals (62.21%) showed similar and higher relative frequency values. Conclusions: Black individuals had greater prevalence of long face pattern, followed by Brown, White and Yellow individuals. The prevalence of long face pattern was 14.06% in which 13.39% and 0.68% belonged to moderate and severe subtypes, respectively.

Occlusal characteristics and orthodontic treatment need in black adolescents in Salvador/BA (Brazil): an epidemiologic study using the Dental Aesthetics Index

OBJECTIVE: The objective of this article is to evaluate the need of orthodontic treatment, prevalence and severity of the malocclusions in individuals of black ethnicity in a representative sample of schoolchildren of the city of Salvador/Brazil, as well as to verify if the malocclusion was affected by socio-demographic conditions such as age and gender. METHODS: The reference population was constituted of schoolchildren with age between 12 and 15 years, enrolled in public and private schools. The malocclusion was evaluated in 486 students of black ethnicity, with ages varying from 12 to 15 years, selected in random sample in multiple stages. The adopted significance level was 1% and the power of the test was 90%. A questionnaire registering demographic characteristics was filled out by each individual. The Dental Aesthetics Index (DAI) was used by previously calibrated examiners (kappa 0.89), according to criteria of the World Health Organization. RESULTS: It was verified that most of the individuals (76%) had little or any need for orthodontic treatment. About 24% showed a condition of severe malocclusion, culminating in a vital need for orthodontic treatment. The main occlusal characteristics found in the group with high need of orthodontic treatment were dental crowding and accentuated overjet. The age was positively related to the improvement of the maxillary overjet and to the presence of crowding. CONCLUSION: The development of public politics that aim the insertion of orthodontic treatment among the procedures of health programs, with the implementation and development of specialized centers, is fundamental.

OBJETIVO: averiguar a necessidade de tratamento ortodôntico, prevalência e severidade das más oclusões em indivíduos negros numa amostra representativa de escolares da cidade de Salvador/BA (Brasil), além de determinar se as más oclusões eram afetadas por condições sociodemográficas como idade e sexo. MÉTODOS: o desenho epidemiológico foi transversal, e a população de referência se constituiu de escolares com idades entre 12 e 15 anos, matriculados em escolas de primeiro e segundo graus, públicas e privadas. Participou do estudo um total de 486 indivíduos sorteados em amostra probabilística em múltiplo estágio. O nível de significância adotado foi de 1% e o poder do teste foi de 90%. Aos participantes foram aplicados questionários registrando características demográficas e, depois, avaliados por examinadores previamente calibrados (Kappa 0,89), utilizando-se o Índice de Estética Dentária (IED) segundo critérios da Organização Mundial de Saúde. RESULTADOS: constatou-se que a maioria dos indivíduos (76%) observados nesse estudo possuía pouca ou nenhuma necessidade de tratamento ortodôntico. Cerca de 24% apresentaram uma condição de má oclusão severa, acarretando uma imprescindível necessidade de tratamento ortodôntico. As principais características oclusais encontradas no grupo com maior necessidade de tratamento ortodôntico foram apinhamento dentário e overjet maxilar acentuado. A idade foi positivamente relacionada com a melhora do quadro do overjet maxilar e com a presença de apinhamento dentário. CONCLUSÃO: torna-se fundamental o desenvolvimento de políticas públicas que objetivem a inserção do tratamento ortodôntico entre os procedimentos dos programas de saúde, com a implementação e desenvolvimento de centros especializados.

Influence of third molar space on angulation and dental arch crowding.

The influence of the third molars on mandibular incisor crowding has been extensively studied but remains controversial. The purpose of this study was to ascertain whether, in Mongolian subjects, the lower third molar can affect anterior crowding and/or the inclination of teeth in the lower lateral segments. Panoramic radiographs, 45° oblique cephalograms, and dental casts were taken from Mongolian subjects (age range 18.3-24.1 years, mean 21.0 years) exhibiting impaction of all four third molars and an Angle Class I molar relationship. The Ganss ratio was calculated using panoramic radiographs, whereas the gonial angle and angulation of lower canines, premolars and molars were measured using 45° oblique cephalograms. Little's index of irregularity was calculated using dental casts. Significant relationships between the angulation of the third and second molars and between the first molars and second premolars were found. Conversely, there was no significant correlation between the angulation of third molars, first premolars and canines. The Ganss ratio calculations showed that the lower first and second molars and the second premolars inclined mesially if there was insufficient space for the lower third molars. However, there was no significant correlation between Little's index of irregularity and third molar angulation. Furthermore, although the third molar influences the lateral segments, no obvious relationship between the third molar and anterior crowding was observed. Therefore, the angulation of the third molar appears not to cause anterior crowding.

Dental crowding: the role of genetics and tooth wear.

OBJECTIVE: To evaluate the role of genetics and tooth wear in the etiology of dental crowding through the analysis of a split indigenous Amazon population. MATERIALS AND METHODS: Dental crowding prevalence (n  =  117), tooth wear (n  =  117), and inbreeding coefficient (n  =  288) were compared for both villages. A biometric investigation was performed by dental cast analysis of 55 individuals with no tooth loss. Mann-Whitney statistics, independent t-tests, and Fisher exact tests were used at P < .05. RESULTS: A high coefficient of inbreeding was confirmed in the resultant village (F  =  0.25, P < .001). Tooth wear was not significantly different (P  =  .99), while a significantly higher prevalence of dental crowding was confirmed in the original village (PR  =  6.67, P  =  0.02). Forty dental arches (n  =  20) were examined in the new group, and only one (2.5%) had a dental crowding ≥ 5 mm. In the original villages, we found 20 arches (28.6%) with dental crowding. No difference was observed for tooth size, while larger dental arch dimensions explained a lower level of dental crowding in the resultant village. CONCLUSIONS: Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on dental crowding and emphasize the role of heredity, exacerbated through inbreeding, in the etiology of this malocclusion.

An assessment of interocclusal space in a dentate Nigerian population.

AIMS AND OBJECTIVES: To determine the average interocclusal space values in a dentate Nigerian population,and to examine the effect of gender, age and different molar relationships on the values obtained. SUBJECTS AND METHODS: Three hundred and fifty one subjects mainly of Yoruba extraction with ages ranging from 16 to 78 years were involved in the study. They included 165 males and 186 females. Inclusion criteria in the study included the presence of a stable posterior occlusion with all first molars present and the absence of moderate to deep wear facets suggestive of parafunction. Subject's occlusal dimensions were measured with a calliper at rest and in occlusion. Interocclusal distances were determined by subtracting the occlusal vertical dimension from the rest vertical dimension. The Angles molar relationship was then recorded for each subject. RESULTS: The average freeway space was 2.93 mm with a standard deviation of 1.38; with the females having marginally higher values. The mean values according to age groups were 15-25 years: 3.15 mm, 26-35 years: 2.68 mm, 36-45 years: 2.66 mm, 46-55 years: 3.2 2mm, 56-65 years: 2.74 mm and 66 years and over: 3.10mm.Class Imolar relationship predominated in the sample with 312 patients (88.9%).Nineteen patients (5.4%) had Class II and 20 patients (5.7%) had Class III.Mean freeway space values for Class I, Class II and Class III were: 2.84 mm, 3.88 mm and 3.37 mm respectively. The difference in values was statistically significant. CONCLUSION: The average interocclusal space amongst the population assessed was 2.93 mm; a value which is similar to that previously reported for Nigerians. Marginally higher values were observed in females while the 26-35 and 36-45 year old groups had lower values than the other age groups. Angle's Class II and III subjects had higher values when compared to class I subjects and was statistically significant. A multi-centre study is recommended to assess possible ethnic variations in these values.

Degenerative changes of the temporomandibular joint. Relationship to ethnicity, sex and occlusal supporting zones based on a skull material.

OBJECTIVE: The first aim of this study was to examine a contemporary human skull material for possible ethnic differences in respect of degenerative changes in the temporomandibular joints (TMJs). A second aim was to see if there was any correlation between such changes and occlusal support in any of the two groups and, if so, if this correlation was sex-related. MATERIALS AND METHODS: The material consisted of 129 Caucasian skulls and 76 skulls from Afro-Americans. Ninety-four of the Caucasian skulls came from males (73%) and the corresponding figure for the Afro-Americans was 40 (53%). Their mean age at death was 46 years (range: 19-89 years) and 37 years (range: 18-70 years), respectively. RESULTS: Dental status was in general poor and 13% of the Afro-Americans and 26% of the Caucasians were edentulous. Form and surface changes of the TMJs were more common in the present material compared to most previous studies. No differences could be found between the two ethnic groups in respect of degenerative joint changes in the TMJs. In men, no correlation of clinical relevance could be found between severity of joint changes and occlusal support. However, in both Caucasian and Afro-American women, such a correlation was obvious, especially in higher age. CONCLUSIONS: The present findings give no evidence for any differences in the prevalence of degenerative changes in the TMJs in Caucasians and Afro-Americans. The strong correlation found between such changes and occlusal support in women but not in men might be explained by hormonal differences.

Intermaxillary tooth-size discrepancies in different sexes, malocclusion groups, and ethnicities.

INTRODUCTION: To achieve proper occlusion, practitioners must consider tooth-size discrepancies between the jaws. Previous studies have shown considerable differences in tooth sizes between sexes, ethnicities, and malocclusion categories. The aim of this study was to compare mean tooth-size statistics between these groups, specifically determining a maxillary or a mandibular excess tooth-size discrepancy in clinically relevant cases. METHODS: This study involved 306 subjects of varying sex, ethnicity, and malocclusion category, randomly chosen from the treatment population of the orthodontic clinic at the New Jersey Dental School, University of Medicine and Dentistry of New Jersey. The prevalence of discrepancies (±1 and 2 SD) between all groups and within groups was measured. RESULTS: Fifty percent of the subjects had anterior Bolton tooth-size discrepancies, and 41% had overall Bolton tooth-size discrepancies of ±1 SD. Tooth-size ratios compared with analysis of variance (ANOVA) showed no significant correlation between and among the sexes, ethnicities, and malocclusion groups. Compared with Caucasian and Hispanic patients, African-American patients had significantly greater odds of having a clinically significant (±2 SD) anterior ratio. When we compared the numbers of subjects above or below the clinically significant ratio, there was equal distribution of maxillary and mandibular excess in Class II and Class III patients. Caucasian and African-American patients had equal distributions of maxillary and mandibular excess, whereas Hispanic patients displayed a higher bias toward mandibular excess. CONCLUSIONS: Tooth-size discrepancies are common in orthodontic populations and are evenly distributed among sex, ethnicity, and malocclusion category, with some exceptions.

Maloclusiones y su impacto psicosocial en estudiantes de un liceo intercultural / Malocclusions and its psychosocial impact in intercultural highschool students

Las maloclusiones están consideradas como la tercera patología oral de mayor prevalencia e impacto en el mundo, a pesar de esto son pocos los estudios en Chile que abordan el tema y consideran sus consecuencias en la calidad de vida o su relación con grupos poblacionales específicos. El objetivo de este estudio es determinar la prevalencia y su impacto psicosocial en jóvenes que estudian en un liceo con población indígena. Se realizó un estudio descriptivo de corte transversal, en 129 alumnos, 73,6 por ciento pehuenche, del Liceo de Ralco; se utilizó el Índice Estético Dental para cuantificar la magnitud de las maloclusiones y un Cuestionario de Autoimagen para evaluar el aspecto psicosocial. Los resultados muestran una prevalencia del 67,4 por ciento y un 21,7 por ciento para el nivel discapacitante de maloclusiones, siendo significativamente mayor en población pehuenche y rural, valores por sobre el de estadísticas nacionales e internacionales. A más de la mitad de los jóvenes las maloclusiones le ocasionan problemas para relacionarse con sus pares. Todo lo anterior hace necesario implementar estrategias preventivas y curativas que den solución a este problema.

Malocclusions are regarded as the third oral disease with most prevalence and impact in the world, despite this there are few studies in Chile that address the issue and consider their impact on the quality of life and relationship to specific population groups. The aim of this study is to determine the prevalence and psychosocial impact on young people studying in a high school with indigenous people. We performed a descriptive cross-sectional study in 129 students, 73.6 percent pehuenche, of Ralco High-school; Dental Aesthetic Index was used to quantify the malocclusion magnitude and a Selfimage Questionnaire for assessing psychosocial aspect. The results show a prevalence of 67.4 percent and 21.7 percent for disabling malocclusions level, was significantly higher in pehuenche and rural population, this values are over national and international statistics. More than half of youngs have troubles to relating with their peers to cause of malocclusion. This requires the implementation of preventive and curative strategies providing a solution to this problem.

Immigrant background and orthodontic treatment need. Quantitative and qualitative studies in Swedish adolescents.

During the last three decades there has been an increased influx of refugees and immigrants into Scandinavia. The overall aim of this thesis was primarily to improve our knowledge of malocclusion and orthodontic treatment need, both normative and self-perceived, in adolescents of varying geographic origin. A further aim was to determine whether any differences with respect to perception of general appearance and psychosocial well-being were related to geographic origin. Papers I and II concerned self perceived and normative orthodontic treatment need. About 500 12-13 year-old subjects, stratified into different groups: A-Sweden, B-Eastern/Southeastern Europe, C-Asia and D-other countries, answered a questionnaire and underwent clinical examination by the author. In paper III the association between the two variables in papers I and II was investigated. Paper IV was a follow up study, at 18-19 years of age, of the relationship between geographic origin and prevalence of malocclusion, self-perceived treatment need, temporomandibular symptoms and psychosocial wellbeing. In Paper V a qualitative study of 19-20-year-old subjects was conducted, to identify the strategies they had adopted to handle the issue of persisting poor dental aesthetics. The main findings were that at 12-13 years of age, immigrant subjects had a lower perceived orthodontic treatment need than subjects of Swedish background. Girls of Swedish background had the highest self-perceived treatment need, whilst girls of non-Swedish background were most concerned that fixed appliance therapy would be painful. In a few of the clinical variables measured at 12-13 years of age, the Swedish group exhibited the greatest space deficiency and irregularity in both the maxillary and mandibular anterior segments and greater overjet, compared to the Eastern/Southeastern European and Asian groups. The clinical implications were negligible. The orthodontic treatment need according to "Index of Orthodontic Treatment Need--Dental Health Component" (IOTN-DHC) grades 4 and 5, ranged from 30 to 40 per cent, without any inter-group differences. There were strong associations between subjects perceiving a need for orthodontic treatment and IOTN-DHC grades 4 and 5, anterior crossbite and avoiding smiling because they were self-conscious about their teeth. At the age of 18-19 years, the frequency of malocclusion was similar in all groups. Subjects of Asian origin had a higher self-perceived orthodontic treatment need than their Swedish counterparts and a higher frequency of headache than those of Eastern/Southeastern European origin. Psychological wellbeing was reduced in nearly one quarter of the sample, more frequently in girls than boys. No association was found between self-perceived orthodontic treatment need and psychological wellbeing. The theory "Being under the pressure of social norms" was generated in Paper V, and it can be applied to improve our understanding of young adults who have adjusted to living with poor dental aesthetics and also aid to identify those who are not as well-adjusted and would probably benefit from treatment. Undisclosed dental fear is an important barrier to acceptance of orthodontic treatment in early adolescence. Despite demographic changes due to immigration, no major change in the prevalence of malocclusion and normative orthodontic treatment need has been disclosed. This does not apply to adolescents and adults who immigrated at an older age.