Are malocclusions more prevalent and severe now? A comparative study of medieval skulls from Norway

Characteristics of dental malocclusion in a 18th/19th century population from Radom (Poland)

OBJECTIVE

The aim of the study was to assess the diachronicity of factors that produce malocclusion from the 18th century to the present.

MATERIALS

A total of 74 adult individuals Radom (Poland) of both sexes were examined (males: 46, females: 28).

METHODS

The skulls were grouped according to the type of malocclusion found: i) anterio-posterior (skeletal Class I/II/III), ii) transverse (cross bite/scissor bite), and iii) vertical (open bite/deep bite).

RESULTS

Normal bites were recorded in 14 % (10/74) of the study group. Malocclusion was observed in the remaining cases (64/74, 86 %). Class I was diagnosed most often (53 %), and Class III (8 %) was the least common in the study group.

CONCLUSIONS

The observed order of frequency of Angle's Classes (I > II > III) in the population from Radom indicates malocclusion was similar to that of the contemporary population. In the population from Radom, similar to other contemporary European populations, Class II defects were found at a higher frequency than Class III defects.

SIGNIFICANCE

The research demonstrates the diachronic nature of the factors that produce different types of malocclusion in Polish populations over the past four centuries, even if these factors cannot be identified.

LIMITATION

The main limitation of this research is the relatively small sample size.

SUGGESTIONS FOR FURTHER RESEARCH

Future studies should evaluate malocclusion in older populations from Radom and other areas of Poland and Europe.

The Effects of Malocclusion Among Priests in Enugu, Nigeria: An Anglican Church-Based Study

Malocclusion refers to the departure from the normal relationship of teeth to other teeth in the same and opposing arch. It can negatively impact on facial appearance and the quality of life of a person. The present study aimed to investigate the influence of malocclusion on the role of priests as counsellors and preachers in Nigeria as perceived by church members. This was a cross-sectional survey of 112 church members who completed an electronic questionnaire. Thirty-five (31.3%) participants said unattractive dental appearance (malocclusion) will impact negatively on their acceptance of the priest's gospel message. Twenty-seven (24.1%) said dental appearance will influence the choice of priest that they go to for counselling while 71 (63.4%) said it will not. The study found that though unattractive teeth arrangement did not significantly affect the priest's duties as it pertains to sermons and counselling, awareness on the importance of orthodontic care among the clergy is necessary and should be encouraged among all spiritual leaders.

Evaluation of the effect of extraction in comparison to distalization on the maxillary third molars in class II malocclusion: a retrospective study

OBJECTIVE

To compare the effects of first premolar extraction versus distalization on the vertical position and mesiodistal angulation of maxillary third molars (MxM3) in adolescent class II patients.

METHODS

The panoramic x-rays (OPGs) of 200 adolescent class II patients with developing MxM3s were screened. The chosen sample consisted of 2 groups: Group 1 (Distalization) comprising 48 MxM3s, and Group 2 (Extraction) comprising 50 MxM3s. The pre- and post-treatment OPGs were traced to detect the mesiodistal angulation changes of the second molars (MxM2) and MxM3s.

RESULTS

The angulation and vertical position of the MxM3s at T0 & T1 were also evaluated using Archer's classification. The distalization group presented a non-significant decrease in the mean angulation of MxM2 and MxM3 (-2.4o & -4.5o uprighting respectively). In the extraction group, both MxM2 and MxM3 presented a highly significant decrease in the mean angulation (-10.5o & -11o uprighting respectively). The angulation and vertical position change of MxM3 significantly improved in the extraction group when compared to the distalization group (P < .001).

CONCLUSION

Significant uprighting and occlusal positioning of the maxillary third molars occurred in the premolar extraction treatment group when compared to the distalization treatment group. The results of the current study highlight the importance of recognizing maxillary third molars during orthodontic treatment planning of Class II malocclusion cases.

Effects of Diet Consistency on Rat Maxillary and Mandibular Growth within Three Generations-A Longitudinal CBCT Study

BACKGROUND

In this study, wistar rats were used to examine the impact of diet consistency on maxillary and mandibular growth over three generations.

METHODS

In this investigation, a breeding sample of 60 female and 8 male wistar rats was used. Measuring was only performed on female animals. The first generation's primary breeding sample consisted of 20 female wistar rats that were 30 days old and 4 male rats that were also 30 days old; two subsequent generations were created from these animals. At the age of 100 days, CBCTs were collected of all male rats. Twenty-eight craniofacial landmarks were selected for the linear measurements on stl format extracted from the DICOM files. A Bonferroni test was performed for the statistical analysis.

RESULTS

Means of measurements of all soft diet groups compared to corresponding measurements of the hard diet groups were significantly different. According to linear measurements, there was statistical difference on the maxillary measurements between the soft diet groups of the first and third generation, while the rest did not appear to have any statistical difference. There was significant difference for the mandibular dimensions only when the first generation soft diet group was compared with the third generation soft diet group.

CONCLUSIONS

Food consistency has a significant impact on the growth and development of the maxilla and mandible. Soft diet habits may result in retrognathic mandible, and narrower maxilla.

Long-Term Effect of Diet Consistency on Mandibular Growth within Three Generations: A Longitudinal Cephalometric Study in Rats

BACKGROUND

This study investigated the effect of diet consistency on mandibular growth of Wistar rats through three generations.

METHODS

A total breeding sample of 60 female and 8 male Wistar rats were used in this study. Measurements took place only on female animals. Twenty female Wistar rats at 30 days old and four male rats at 30 days old comprised the primary breeding sample of the first generation, and from these animals two different generations were reproduced. Lateral cephalometric X-rays were taken from all female rats at the age of 100 days. A total of 7 craniofacial landmarks were selected for the linear measurements, and 12 curves and 90 landmarks were selected for geometric morphometric analysis of the lateral X-rays. Bonferroni test and a permutation test were performed for the statistical analysis.

RESULTS

Means of measurements of all soft diet groups compared to hard diet groups were significantly smaller. According to linear measurements, there was a significant difference only between the first-generation soft diet with the third-generation soft diet group. According to geometric morphometric analysis, the statistical differences appeared on the condylar process and the angle of the mandible.

CONCLUSIONS

The soft diet could be responsible for less mandibular growth, and this information might be passing through generations.

Influence of age and diet consistency on the oral muscle pressure of orthodontically treated and untreated subjects with normal occlusion and comparison of their 3D facial shape

OBJECTIVES

(1) To investigate the effect of age and diet consistency on maximum lips, tongue and cheek pressure of orthodontically treated and untreated subjects with normal, Class I dental occlusion, (2) to find out whether there is a muscle imbalance between anterior tongue and lip pressure in the same subjects at different ages and (3) to compare the 3D facial shape of treated and untreated individuals.

MATERIAL AND METHODS

Subjects with normal occlusion were prospectively grouped into orthodontically treated/untreated and in children/adolescents/adults. Iowa Oral Performance Instrument was used to record the maximum muscle pressure. Two-way ANOVA and Tukey post hoc test analysed age-specific differences in muscle pressure. Two-way ANCOVA analysed the effect of diet consistency on muscle pressure. Lips and tongue imbalance was analysed using z-scores and 3D faces using a generalized Procrustes analysis.

RESULTS

One hundred thirty-five orthodontically untreated and 114 treated participants were included. Muscle pressure was found to increase with age in both groups, except for the tongue in treated subjects. No differences in the balance between lips and tongue muscle pressure were found, but a higher cheek pressure in untreated adults (p<0.05) was observed. 3D facial shapes showed subtle differences. Untreated subjects with soft diet consistency showed lower lip pressure (p<0.05).

CONCLUSION

Oral muscle pressure of orthodontically treated patients without relapse does not differ from that of untreated patients with Class-I occlusion.

CLINICAL RELEVANCE

This study provides normative lip, tongue and cheek muscle pressure in subjects with normal occlusion, which can be used for diagnosis, treatment planning and stability.

Distribution of Malocclusion Traits in the Pediatric Population of Milan: An Observational Study

Background: Epidemiological investigations define the prevalence and distribution of the various types of malocclusions, and can help to identify etiological factors and set the most correct orthodontic therapy. Aim: The goal of this study was to verify the prevalence and distribution of various types of malocclusions in the pediatric population. Methods: The study was performed on a sample of 350 patients (ages 5-9) being treated at the ASST Grande Ospedale Metropolitano Niguarda in Milan. A comparison was presented with one similar epidemiological investigation conducted 22 years earlier by the same researchers. The values of the malocclusion indices were reported from the cephalometric analyzes of the patients and were differentiated on the basis of gender and ethnicity. Results: The predominant traits of malocclusion in the general population of the analyzed sample were: skeletal class II (47.43%), hyper-divergence (40.86%), maxillary retrusion (46%), mandibular retrusion (66%), maxillary hypoplasia (50%), mandibular hypoplasia (49.14%), Wits index > 2 mm (22.57%); overjet > 4 mm (31.1%) and overbite > 4 mm (24.86%). Substantial differences were found between Italian patients and patients belonging to different ethnic groups in almost all parameters, and between the male and female genders in some of them. Patients in the 2000 study had a higher prevalence of Class II and hyper-divergence. Conclusions: This epidemiological investigation can suggest different approaches in setting the orthodontic treatment plan based on the ethnic group of the patient taken in charge and encourage more specific and large-scale analytical studies on the subject.

Unexpected malocclusion in a 13,000-Year-old Late Pleistocene young woman from Mexico

To analyze the etiological factors behind the malocclusion of a Late Pleistocene woman (named Naia), who is the best-preserved of the earliest individuals of the American continent. The examination of Naia’s malocclusion was performed through cephalometric and occlusal analyses, and by measuring her mandible. Her data were then compared to published data for modern, medieval, and postmedieval samples and seven Late Pleistocene individuals. Naia presented her permanent dentition fully erupted, except for the impacted mandibular third molars. She presented a class II molar malocclusion with crowding. The dental widths and mandible measurements were similar to or smaller than modern standards. The degree of dental wear was light. The cephalometric analysis confirmed a skeletal class II relationship, with a retrusive mandible and protruded upper incisors. Naia’s mild level of dental wear is consistent with a low masticatory force, in a time when the norm was a high amount of grinding. The low masticatory forces help explain Naia’s small jaws and crowding. However, it does not clarify Angle’s class II relationship. Naia is an example that environmental factors are insufficient to explain the onset of malocclusions and emphasizes the importance of understanding hereditary factors’ role.

A Cross-Sectional Evaluation of Self-Perceived Orthodontic Treatment Needs Amongst Tribal Adolescent With Remote Access to Orthodontic Treatment Using a Simplified Malocclusion Index

Background:

Self-perceived orthodontic treatment need is strongly influenced by what is perceived to be the esthetic norm amongst a community, and reluctance toward treatment amongst adolescents with clinically ascertained malocclusion may often be due to readily remediable factors. Of particular interest is the prevalence of malocclusion amongst such communities as a probable indicator of the role of diet and genetics in establishing a predominant clinical phenotype that may also play a role in the construct of what is perceived as the esthetic norm amongst the community, thereby influencing the self-perceived need for treatment. Studies aimed at evaluating the association between self-perceived esthetics, and self-perceived treatment need have not been performed amongst a population with no prior exposure to orthodontic treatment

Objectives:

The purpose of this study was to evaluate the self-perceived orthodontic treatment need amongst the tribal adolescents belonging to regions with remote access to orthodontic treatment by way of a verbally assigned index and to also identify the reasons of reluctance toward treatment to better understand how to make orthodontic treatment readily accessible to such populations.

Participants, Materials, and Methods:

The agency areas of Paderu located at 18.0833°N 82.667°E and Parvathipuram located at 18°46'N 83°25'E are 2 revenue districts of Visakhapatnam and Vizianagaram, respectively, in the state of Andhra Pradesh, India, that are home to various tribal populations with remote access to orthodontic treatment. A total of 2,016 school-going tribal adolescents of the Paderu revenue division and 819 tribal adolescents of the Parvathipuram revenue division were examined to ascertain the prevalence of malocclusion. Necessary consent and permissions were obtained from the tribal authorities, the school authorities, parents, and the institutional ethical clearance committee. The screening was done utilizing natural daylight in compliance with infection prevention and control protocol. Clinical examination aimed at categorizing the observed occlusion into either ideal occlusion or one of the three classes of Angle’s class I, II, and III malocclusions. The Simplified Malocclusion Index For Layperson Evaluation (SMILE) was verbally assigned in the vernacular language while interacting with each child and the findings made note of for calculation of relevant scores related to their orthodontic awareness, self-esteem as related to self-perceived esthetics, and their self-perceived need for treatment. Reasons for reluctance to undergo treatment were noted down if expressed. An initial group of 31 adolescents categorized as presenting with clinical malocclusion were randomly picked up and assigned the SMILE index a second time to assess the reliability of the index by way of Cohen’s kappa statistic.

Results:

The initial test group of 31 individuals assigned the SMILE twice showed a Cohen’s kappa of 0.93 validating almost perfect intraoperator agreement. The SMILE index revealed that 80.95% of the adolescents of Paderu revenue division had orthodontic awareness and 79.51% had self-perceived esthetics but only 15.97% felt a need for orthodontic treatment. Pearson’s Chi squared statistical analysis indicated a gender bias related to the self-perceived need for orthodontic treatment ( X 2 [1, N = 1,371] = 19.71, P < .001). The Index assigned to the Parvathipuram division revealed that 77.04% had orthodontic awareness and 78.38 had self-perceived esthetics but only 6.95% felt the need for orthodontic treatment. Pearson’s Chi squared statistical analysis indicated a gender bias related to the self-perceived need for orthodontic treatment ( X 2 [1, N = 764] = 4.95, P = .02).

Conclusion:

The self-perceived need for orthodontic treatment is often based on the self-perceived esthetics of an individual or the self-esteem as influenced by the perceived esthetic norm of the community. Orthodontic treatment of adolescents with borderline malocclusion derangements requires careful ascertaining of the actual perceived need of the patient to enable the rendering of a justifiable orthodontic treatment with the complete trust of the young patient. This helps build community trust in regions where orthodontic treatment has not yet made in roads and may help ensure higher end of treatment satisfaction levels.

The Jaw Epidemic: Recognition, Origins, Cures, and Prevention

Contemporary humans are living very different lives from those of their ancestors, and some of the changes have had serious consequences for health. Multiple chronic "diseases of civilization," such as cardiovascular problems, cancers, ADHD, and dementias are prevalent, increasing morbidity rates. Stress, including the disruption of traditional sleep patterns by modern lifestyles, plays a prominent role in the etiology of these diseases, including obstructive sleep apnea. Surprisingly, jaw shrinkage since the agricultural revolution, leading to an epidemic of crooked teeth, a lack of adequate space for the last molars (wisdom teeth), and constricted airways, is a major cause of sleep-related stress. Despite claims that the cause of this jaw epidemic is somehow genetic, the speed with which human jaws have changed, especially in the last few centuries, is much too fast to be evolutionary. Correlation in time and space strongly suggests the symptoms are phenotypic responses to a vast natural experiment-rapid and dramatic modifications of human physical and cultural environments. The agricultural and industrial revolutions have produced smaller jaws and less-toned muscles of the face and oropharynx, which contribute to the serious health problems mentioned above. The mechanism of change, research and clinical trials suggest, lies in orofacial posture, the way people now hold their jaws when not voluntarily moving them in speaking or eating and especially when sleeping. The critical resting oral posture has been disrupted in societies no longer hunting and gathering. Virtually all aspects of how modern people function and rest are radically different from those of our ancestors. We also briefly discuss treatment of jaw symptoms and possible clinical cures for individuals, as well as changes in society that might lead to better care and, ultimately, prevention.

Hypodontia and retention of third molars in Norwegian medieval skeletons: dental radiography in osteoarchaeology

OBJECTIVES

The objective of the present study is to compare the prevalence of third molar hypodontia in matched medieval and modern Norwegian sample with the aim to examine whether there are secular changes in dental anomalies. A second objective is to determine the level of primary retention of third molar in the medieval sample.

MATERIAL AND METHODS

The medieval material consisted of 130 adult skulls, hypodontia of third molars was determined using radiography and compared to findings with panoramic film images of 400 15-year-old individuals from a contemporary Norwegian epidemiological study.

RESULTS

Among 130 medieval skulls, hypodontia of third molar was found in 36 skulls (27.7%), and in the contemporary sample, hypodontia of third molar was found in 69 individuals (17.2%). Female predominance, although not statistically significant, was observed both in the medieval and in the contemporary group. The third molars showed absence in the mandible (21.5%) more often than the maxilla in the medieval sample, and in both jaws (11.2%) in the contemporary material. In the medieval sample, only 7.7% of the individuals had at least one retained third molar.

CONCLUSION

No increase in the frequency of third molar hypodontia was found from the medieval period until today. The frequency of retained third molars seems to have increased from the medieval period to modern times. The use of radiographic examination in addition to macroscopic inspection can give us a better understanding of the aetiology on a number of conditions in human skeletal remains.

Influence of head and linear growth on the development of malocclusion at six years of age: a cohort study

The aim of this article was to evaluate the influence of biological and sociobehavioral factors on the development of malocclusions in children. This is a cross-sectional study nested in a cohort of 350 children who participated in a community intervention study. After six years, an active search identified 290 children with occlusal abnormalities. Socioeconomic status, linear growth, and nutritional status of the child at birth and at the time of measurement, as well as dietary and sucking habits, were investigated. Malocclusions were evaluated across three spatial planes - anteroposterior, vertical, and transverse. The prevalence of these anomalies was 64.5%, primarily in the anteroposterior plane. The logistic regression analysis revealed that pacifier use for 60 months or more, stunting as measured at age six, and reduced gain in head circumference from birth to six years of age, were significantly associated with the development of malocclusion in childhood. Head circumference and linear growth are associated with occlusal anomalies in infants, independent of pacifier sucking.

Photoelastic analysis of stress distributions in the root-bone interface when applying various orthodontic methods to subside lower anterior crowding

Dental crowding is a prevalent problem in modern society. Various factors, including different bracket systems and geometry of wire, influence the outcome using superelastic wire in the alignment stage of treatment. Currently, the use of light round wire instead of large-sized rectangular wire is emphasized to avoid powerful torsional stiffness. However, these guidelines lack scientific evidence for support. They have been written predominantly based on clinical experience. Therefore, the purpose of this study was to evaluate how factors such as bracket systems and wire geometry affect the stress distribution at the root-bone interface. Models using a photoelastic material (PL-3) to simulate bone tissue were fabricated. The simulated teeth were arranged as in lower anterior crowding. Then, the crowded teeth were subjected to orthodontic treatment with various types of bracket, ligating approaches using ligature wires of different sizes, shapes, and materials. Photoelastic images of the bone area of the models were obtained and compared. The results showed that wire size plays a more significant role than the material or cross-sectional shape of the wire in affecting the stress distribution at the simulated root-bone interface. The teeth ligated with a larger cross-sectional diameter of wire showed the application of excessive torque, which may cause root resorption and slow down tooth movement. These results not only demonstrate the scientific evidence backing clinical experience but also can be a useful reference for further clinical application.

The study of dental occlusion in ancient skeletal remains from Mallorca (Spain): A new approach based on dental clinical practice

Occlusal characteristics, fundamental to assess the presence of malocclusion, have been often unexplored in bioarchaeological analyses. This is largely due to the fragmented condition of the skeletal remains. By applying a method that considers dental and maxillary features useful to evaluate occlusion in ancient fragmentary material, the purpose of this work is to define the occlusal features and explore the causes of malocclusion in a mediaeval population from Mallorca. The findings of this study suggest that normocclusion was present in ca. 60% of the individuals (N=31), and that some characteristics, such as molar relationship, were slightly different from those of modern populations. The analysis of the occlusal features revealed for example that open-bite was absent in 85% of the sample, posterior open-bite was completely absent and overbite and overjet were normal in around 90% of the individuals. Statistically significant correlations between canine and molar relationships and between molar relationship and dental wear of the superior and inferior canines and incisors were observed. In addition, wear could affect the curve of Spee. All these findings strengthen the hypothesis that in ancient times malocclusion was not as generalized as in modern times. Although the factors that lead to malocclusion throughout centuries could have several causes, we suggest that in this population dental wear, which is strongly associated with the diet, was the fundamental causing factor.

Extractions, retention and stability: the search for orthodontic truth

Background and objectives

From the beginnings of modern orthodontics, questions have been raised about the extraction of healthy permanent teeth in order to correct malocclusions. A hundred years ago, orthodontic tooth extraction was debated with almost religious intensity by experts on either side of the issue. Sheldon Friel and his mentor Edward H. Angle both had much to say about this controversy. Today, after significant progress in orthodontic practice, similar arguments are being voiced between nonextraction expansionists and those who see the need for tooth extractions in some orthodontic patients. Furthermore, varying concepts of mechanical retention of treatment results have evolved over the years which have been misinterpreted as enhancing natural orthodontic stability.

Materials and methods

In this essay, representing the Ernest Sheldon Friel Memorial Lecture presented in 2016 at the 92nd Congress of the European Orthodontic Society, a full spectrum of evidence from biology, anthropology and history is critically discussed in the search for truth among highly contested orthodontic variables: extraction versus nonextraction, fixed retention versus limited retention, and rationalized stability versus biological homeostasis.

Conclusions and implications

Conscientious clinicians should try to develop individualized treatment plans for their patients, and not be influenced by treatment 'philosophies' with untested claims in clinical orthodontics.

Pattern of clefts and dental anomalies in six-year-old children: a retrospective observational study in western Norway

OBJECTIVES

Clefts of the lip and/or palate (CL/P) are the most common congenital disorders of the head and neck. In Norway, the incidence is 1.9/1000 live births. The aim of this study was to investigate the frequency and distribution of various types of clefts and dental anomalies in patients treated by the cleft lip and palate (CLP) team in Bergen, Norway.

MATERIAL AND METHODS

The material comprised the records of patients 6 years of age, examined by the CLP team in Bergen from spring 1993 to autumn 2012, incomplete records were excluded. The records of 989 patients were analysed, using frequencies and Chi-square test to compare differences in percentages between groups.

RESULTS

The gender distribution was 58.8% male and 41.2% female. Isolated cleft palate (CP) was the most common condition (39.5%). Clefts of the lip, jaw and palate (CLP) constituted (30%) of cases and (30.5%) had isolated cleft lip (CL). The frequencies of agenesis, supernumerary and peg-shaped teeth were (36.5%), (17.8%) and (7.5%), respectively. Over 50% of the study population were diagnosed with one or more malocclusion. Of the CLP patients, 61.4% had Angle Class III occlusion. Statistical analysis disclosed a positive association of agenesis with Class III occlusion (OR =1.8, p≤ 0.001).

CONCLUSIONS

The findings supported the hypothesis that the distribution of dental anomalies and occlusal disorders varied among patients with CL, CP and CLP. In patients with cleft, there is a twofold chance to get Class III malocclusion in the presence of agenesis.

Association between maternal education and malocclusion in Mongolian adolescents: a cross-sectional study

OBJECTIVE

Malocclusion is a highly prevalent condition, affecting 20-60% of adolescents worldwide. Although its treatment is often expensive and unaffordable for disadvantaged individuals, few studies have examined the relationship between malocclusion and socioeconomic status. We investigated the prevalence of malocclusion among Mongolian adolescents and its association with maternal education in a community-based sample in Mongolia.

DESIGN

Cross-sectional study.

SETTINGS

2 large secondary schools with different backgrounds in Ulaanbaatar, Mongolia.

PARTICIPANTS

Complete dental casts of 557 randomly recruited Mongolian schoolchildren aged 11-16 years were evaluated using the Dental Health Component of the Index of Orthodontic Treatment Need to dichotomise orthodontic treatment requirements. Exclusion criteria were the presence of orthodontic treatment history and absence of maternal educational status. Questionnaires were administered to caregivers to assess socioeconomic status. Poisson regression analysis was performed to examine the association between malocclusion and maternal educational status.

RESULTS

The prevalence of malocclusion requiring orthodontic treatment among all adolescents was 35.2% (95% CI 31.2 to 39.2). In the unadjusted analysis, the prevalence ratio (PR) for malocclusion was higher (PR=1.46; 95% CI 0.96 to 2.20) among adolescents of mothers with a high educational background than among those of mothers with a low educational background. After adjusting for covariates, the PR remained significantly higher (PR=1.72; 95% CI 1.06 to 2.82) among adolescents of mothers with a high educational background. Other socioeconomic status variables, including family income and the educational level of the father, showed no association with malocclusion.

CONCLUSIONS

These findings suggest that malocclusion requiring orthodontic treatment in adolescents is more prevalent among children of mothers with high levels of education. Further studies are needed to clarify the behavioural factors and environmental circumstance that contribute to this.

Cephalometric comparison of cesarean and normal births

Objective:

The aim of this study was to compare cephalometric variables of subjects with normal and cesarean births.

Materials and Methods:

Ninety age- and gender-matched patients, who were treated in Gaziantep University, Faculty of Dentistry Orthodontics Department were equally divided into normal and cesarean groups according to the birth methods reported by their mothers. To eliminate the negative effects of being different in terms of age and gender among parameters, control, and patient groups were matched in the present study. Pretreatment cephalometrics radiographs were used. Six measurements representing sagittal and vertical relationships were evaluated from pretreatment cephalograms using Dolphin Imaging Orthodontics Software was used in this issue by an orthodontist. Kolmogorov–Smirnov test, Student's t-test, and Mann–Whitney U-test were used for statistical comparisons.

Results:

A point-nasion-B point angle (ANB) and Wits values were higher in the normal group, while sella-nasion-A point angle, sella-nasion-B point angle, Frankfort horizontal-mandibular plane angle, and gonion-gnathion-SN plane angle values were higher in the cesarean group. However, the groups showed no significant differences (P > 0.05). ANB angle and Wits values showed high correlation.

Conclusions:

Within the study limitations, the results suggest that the birth method may not have a considerable effect on the development of the craniofacial skeletal system.

Predictors of Third Molar Impaction

The objective of this meta-analysis was to evaluate the prevalence of third molar (M3) impaction worldwide in individuals ≥17 y, from either sex, who had undergone oral radiography and presented with no orofacial syndromes or defects. We performed a literature search using PubMed, ISI Web of Science, and Google Scholar and retrieved English and non-English articles from any period for review. We included studies reporting M3 impaction prevalence based on radiographic examination. Risk of bias was assessed regarding individuals with craniofacial syndromes, prior extraction of permanent teeth, multiple effect size estimates, and studies conflating lack of eruption with impaction. Our search yielded 49 studies involving 83,484 individuals. Worldwide M3 impaction prevalence was found to be 24.40% (95% confidence interval [95% CI]: 18.97% to 30.80%). The odds of M3 impaction in the mandible were 57.58% (95% CI: 43.3% to 68.3%, P < 0.0001) higher than in the maxilla, but we did not detect any difference in the odds of impaction between men and women (18.62%, 95% CI: –4.9% to 48.0%, P = 0.12). Mesioangular impaction was most common (41.17%, 95% CI: 33.8% to 49.0%), followed by vertical (25.55%, 95% CI: 20.0% to 32.0%), distoangular (12.17%, 95% CI: 9.1% to 16.0%), and horizontal (11.06%, 95% CI: 8.3% to 14.6%). Impaction of 1 (42.71%, 95% CI: 30.0% to 56.5%) or 2 (29.64%, 95% CI: 19.5% to 42.3%) M3s was much more common than 3 (12.04%, 95% CI: 7.2% to 19.3%) or 4 (8.74%, 95% CI: 5.2% to 14.5%). There were small differences among impaction prevalence depending on geographic region ( F test, P = 0.049). Selection bias was evident because individuals had to undergo radiographic examination to be included in the analysis. The subgroup analysis by sex was underpowered. Worldwide M3 impaction prevalence is lower than previously reported. The percentage of individuals with impacted M3s is much smaller than the percentage that undergoes clinical treatment for M3 problems.

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.

Individual and contextual determinants of malocclusion in 12-year-old schoolchildren in a Brazilian city

The aim of this study was to describe malocclusion prevalence and its association with individual and contextual factors among Brazilian 12-year-old schoolchildren. This cross-sectional study included data from an oral health survey carried out in Goiânia, Brazil (n = 2,075), and data from the files of the local health authority. The data were collected through oral clinical examinations. The Dental Aesthetic Index (DAI) was used to assess occlusion. The presence of malocclusion (DAI > 25) was used as the dependent variable. The individual independent variables consisted of adolescents' sex and race and their mothers' level of schooling. The clinical variables were caries experience and presence of adverse periodontal condition (calculus and/or gingival bleeding). The contextual variables included type of school and the location of schools in the city's health districts. The Rao-Scott test and multilevel logistic regression were performed. The prevalence of malocclusion was 40.1%. In the final model, significantly higher rates of malocclusion were found among those who attended schools located in less affluent health districts and whose mothers had fewer years of education. Rates were also higher among those presenting calculus and/or gingival bleeding. Malocclusion demonstrated a high prevalence rate and the inequalities in its distribution were determined by individual and contextual factors.

Anterior guidance--movement and stability

Instability of our orthodontic treatment is not uncommon, in particular in the anterior teeth. Given that the mandible is constantly in movement and that the lower and upper teeth regularly meet head-on during normal functioning, one might ask: are the static and normative end of treatment objectives we generally target sufficient to ensure treatment stability?

Phenotypic diversity in white adults with moderate to severe Class II malocclusion

INTRODUCTION

Class II malocclusion affects about 15% of the population in the United States and is characterized by a convex profile and occlusal disharmonies. The specific etiologic mechanisms resulting in the range of Class II dentoskeletal combinations observed are not yet understood. Most studies describing Class II phenotypic diversity have used moderate sample sizes or focused on younger patients who later in life might outgrow their Class II discrepancies; such a focus might also preclude the visualization of adult Class II features. The majority have used simple correlation methods resulting in phenotypes that might not be generalizable to different samples and thus might not be suitable for studies of malocclusion etiology. The purpose of this study was to address these knowledge gaps by capturing the maximum phenotypic variations in a large sample of white Class II subjects selected with strict eligibility criteria and rigorously standardized multivariate reduction analyses.

METHODS

Sixty-three lateral cephalometric variables were measured from the pretreatment records of 309 white Class II adults (82 male, 227 female; ages, 16-60 years). Principal component analysis and cluster analysis were used to generate comprehensive phenotypes to identify the most homogeneous groups of subjects, reducing heterogeneity and improving the power of future malocclusion etiology studies.

RESULTS

Principal component analysis resulted in 7 principal components that accounted for 81% of the variation. The first 3 components represented variation on mandibular rotation, maxillary incisor angulation, and mandibular length. The cluster analysis identified 5 distinct Class II phenotypes.

CONCLUSIONS

A comprehensive spectrum of Class II phenotypic definitions was obtained that can be generalized to other samples to advance our efforts for identifying the etiologic factors underlying Class II malocclusion.

Malocclusion in early anatomically modern human: a reflection on the etiology of modern dental misalignment

Malocclusions are common in modern populations. Yet, as the study of occlusion requires an almost intact dentition in both the maxilla and mandible, searching for the ultimate cause of malocclusion is a challenge: relatively little ancient material is available for research on occlusal states. The Qafzeh 9 skull is unique, as its preserved dentition allowed us to investigate the presence and manifestations of malocclusion. The aim of this study was thus to examine the occlusal condition in the Qafzeh 9 specimen in light of modern knowledge regarding the etiology of malocclusion. We revealed a pathologic occlusion in the Qafzeh 9 skull that probably originated in the early developmental stage of the dentition, and was aggravated by forces applied by mastication. When arch continuity is interrupted due to misalignment of teeth as in this case, force transmission is not equal on both sides, causing intra-arch outcomes such as mesialization of the teeth, midline deviation, rotations and the aggravation of crowding. All are evident in the Qafzeh 9 skull: the midline deviates to the left; the incisors rotate mesio-buccally; the left segment is constricted; the left first molar is buccally positioned and the left premolars palatally tilted. The inter-arch evaluation revealed anterior cross bite with functional shift that might affect force transmission and bite force. In conclusion, the findings of the current study suggest that malocclusion of developmental origin was already present in early anatomically modern humans (AMH) (the present case being the oldest known case, dated to ca. 100,000 years); that there is no basis to the notion that early AMH had a better adjustment between teeth and jaw size; and that jaw-teeth size discrepancy could be found in prehistoric populations and is not a recent phenomenon.

Duration of breastfeeding and distoclusion in the deciduous dentition

OBJECTIVE

This study investigated the association between duration of breastfeeding and occurrence of distoclusion in preschoolers with complete deciduous dentition.

SUBJECTS AND METHODS

A cross-sectional study nested within a cohort of 153 Brazilian children was conducted. The outcome of interest was presence of distoclusion as diagnosed at dental assessment between 3 and 5 years of age. Data on the main exploratory variable (duration of breastfeeding) and other variables that might influence the study outcome (use of dummy/pacifier, bottle feeding, and thumb sucking) were collected by a blinded examiner at 7, 30, 60, 120, and 180 days of life and at dental assessment. Poisson regression was used to test for the association between exposure and the outcome of interest.

RESULTS

The prevalence of distoclusion was 47.7%. Multivariate analysis showed that breastfeeding afforded some protection against distoclusion, after adjusting for confounding factors such as pacifier use and bottle feeding. In children breastfed for 12 months or more, the prevalence of distoclusion at 3-5 years of age was 56% lower than in those breastfed for shorter periods (prevalence ratio=0.44; 95% confidence interval 0.23-0.82).

CONCLUSION

Breastfeeding for 12 months or longer significantly reduces the prevalence of distoclusion in the deciduous dentition.

Dental crowding

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 &lt; .05.

Results:

A high coefficient of inbreeding was confirmed in the resultant village (F  =  0.25, P &lt; .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.

Variability in permanent tooth size of three ancient populations in Xi'an, northern China

OBJECTIVES

This paper compares permanent dental dimensions between three ancient populations that belonged to the same biological population throughout a temporal range of 2000 years to detect temporal trends and metric variation in dentition.

MATERIALS AND METHODS

The samples analysed were dental remains of 4502 permanent teeth from 321 individuals, which were excavated from three archaeological sites: Chang'an (1000-1300 years BP), Shanren (2200 years BP) and Shaolingyuan (3000 years BP) in the Xi'an region (northern China). For each tooth three standard measurements were taken: Mesiodistal (MD) diameter of crown, labiolingual or buccolingual (BL) diameter of crown and length of root (LR).

RESULTS

Three ancient population samples generally displayed the same dental dimensions (p>0.05), whereas some tooth types varied. The Shaolingyuan had larger canine and the smallest maxillary second molars and the Chang'an had the largest mandibular first molars in the MD dimension. The Shanren had the smallest maxillary third molars and mandibular central incisors, and the Chang'an had the smallest maxillary lateral incisors in the BL dimension. In the LR measures, statistically significant differences of five tooth types showed that the Chang'an were smaller than the Shaolingyuan and the Shanren. Comparisons of coefficients of variation for teeth showed that the length of root and third molar usually displayed greater variation.

CONCLUSIONS

Decreasing or increasing trend for crown size does not occur between the ancient populations, while changes in crown size of a few tooth types fluctuate. The root size is more variable than the crown size and is likely to reflect a degenerated trend in a few tooth types.

Zygomaticomaxillary suture shape analyzed with digital morphometrics: reassessing patterns of variation in American Indian and European populations

Typological classification of human zygomaticomaxillary suture (ZMS) shape is often used in forensic assessment of ancestry, following earlier studies reporting higher frequencies of "angled" sutures among American Indians and higher frequencies of "curved" sutures among Caucasians. In this paper we present a new method of digital morphometrics to quantify and compare ZMS shape in 60 American Indian and 60 European crania. Suture outlines were recorded as three-dimensional (3D) contours on digital models of adult male and female crania created with a portable 3D laser scanner. Each contour was represented by about four hundred point coordinates, which were transformed via Fourier analysis into amplitude coefficients suitable for use in linear discriminant analysis. Discriminant functions were created that accurately predicted group membership for 83% of the crania in the sample, after leave-one-out cross-validation. The results were compared with traditional typological classifications based on visual evaluation of ZMS shape, and the contour-based method was found to be more effective than the typological approach. However, the distribution of ZMS types within the two sample groups did not conform to previously reported patterns. This discrepancy indicates that ZMS shape may reflect not only genetic factors, but also environmental factors such as diet and stress. In addition, some evidence for sexual dimorphism in the zygomaticomaxillary complex was observed. Based on these findings, we recommend caution when using ZMS shape analysis in forensic ancestry determination.

Dental occlusion in a split Amazon indigenous population: genetics prevails over environment

Background

Studies examining human and nonhuman primates have supported the hypothesis that the recent increase in the occurrence of misalignment of teeth and/or incorrect relation of dental arches, named dental malocclusion, is mainly attributed to the availability of a more processed diet and the reduced need for powerful masticatory action. For the first time on live human populations, genetic and tooth wear influences on occlusal variation were examined in a split indigenous population. The Arara-Iriri people are descendants of a single couple expelled from a larger village. In the resultant village, expansion occurred through the mating of close relatives, resulting in marked genetic cohesion with substantial genetic differences.

Methodology/Principal Findings

Dental malocclusion, tooth wear and inbreeding coefficient were evaluated. The sample examined was composed of 176 individuals from both villages. Prevalence Ratio and descriptive differences in the outcomes frequency for each developmental stage of the dentition were considered. Statistical differences between the villages were examined using the chi-square test or Fisher's exact statistic. Tooth wear and the inbreeding coefficient (F) between the villages was tested with Mann-Whitney statistics. All the statistics were performed using two-tailed distribution at p≤0.05. The coefficient inbreeding (F) confirmed the frequent incestuous unions among the Arara-Iriri indigenous group. Despite the tooth wear similarities, we found a striking difference in occlusal patterns between the two Arara villages. In the original village, dental malocclusion was present in about one third of the population; whilst in the resultant village, the occurrence was almost doubled. Furthermore, the morphological characteristics of malocclusion were strongly different between the groups.

Conclusions/Significance

Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on occlusal variation of living human populations. They also suggest that genetics plays the most important role on dental malocclusion etiology.

Orthodontic anomalies and malocclusions in Late Antique and Early Mediaeval period in Croatia

OBJECTIVE

Malocclusions are relative infrequently analysed in bioarchaeological investigations and if investigated the samples are very small. This research provides analysis of orthodontic anomalies of even 1118 individuals from the Late Antique (LA) and Early Mediaeval (EM) period. Aims were to describe the prevalence of orthodontic anomalies in this historical period and to analyse which orthodontic anomalies are best suitable for bioarchaeological investigations.

METHODS

1118 skulls were examined for anomalies of tooth number, tooth displacement (rotation, malposition, diastema and crowding) as well as for malocclusions.

RESULTS

The prevalence of hypodontia in the LA was 41.02% and 30.61% in the EM sample. Tooth displacement was noticed in 15.63% individuals from the LA and in 12.42% individuals from EM. About 26% of the LA sample and 7.19% of the EM sample were affected with tooth crowding and the difference was statistically significant.

CONCLUSION

Orthodontic anomalies affecting only one tooth or group of teeth are more suitable for examination in bioarchaeological investigations than orthodontic features requiring presence of both jaws and all or almost all teeth. Clinical investigation protocols and methodology should be adopted for bioarchaeological researches and international standards and recommendations should be established for this kind of investigation on skeletal remains.

Morphological analysis of the skeletal remains of Japanese females from the Ikenohata-Shichikencho site

The aim of this study was to assess morphological differences between early-modern (Edo) Japanese and contemporary Japanese using recently uncovered human female remains at the Ikenohata-Shichikencho site in the Tokyo urban area. In this study, 30 female skeletal remains that still retained the upper and lower first molars and central incisors were selected [early-modern (Edo) Japanese group]. Forty contemporary female Japanese were selected as a control. Analyses by standard methods of geometric morphometrics revealed some morphological differences between the early-modern (Edo) Japanese group and the contemporary Japanese group. For example, the early-modern (Edo) Japanese group exhibited bimaxillary dentoalveolar protrusion, a flat occlusal plane, and a large S-N length. On the other hand, the contemporary Japanese group exhibited slight protrusion of the anterior nasal spine. These findings may be of interest to orthodontists who are studying age variation or temporal differences and could lead to a better understanding of morphological diversity and variability.

Brief communication: Identification reassessment of the isolated tooth Krapina D58 through occlusal fingerprint analysis

High variability in the dentition of Homo can create uncertainties in the correct identification of isolated teeth. For instance, standard tooth identification criteria cannot determine with absolute certainty if an isolated tooth is a second or third maxillary molar. In this contribution, using occlusal fingerprint analysis, we reassess the identification of Krapina D58 (Homo neanderthalensis), which is catalogued as a third maxillary molar. We have hypothesized that the presence/absence of the distal occlusal wear facets can be used to differentiate second from third maxillary molars. The results obtained confirm our hypothesis, showing a significant difference between second and third maxillary molars. In particular we note the complete absence of Facets 7 and 10 in all third molars included in this analysis. The presence of these facets in Krapina D58 eliminates the possibility that it is a third maxillary molar. Consequently it should be reclassified as a second molar. Although this method is limited by the degree of dental wear (i.e., unworn teeth cannot be analyzed) and to individual molars in full occlusion, it can be used for tooth identification when other common criteria are not sufficient to discriminate between second and third maxillary molars.

Clinical practice. Later orthodontic complications caused by risk factors observed in the early years of life

Primary preventive strategies for oral health are an essential public health priority. Paediatricians have frequent contact with families during routine preventive visits in the child's first few years of life and are in an ideal and unique position, to advise families about the prevention of oral diseases in their children. Primary prevention is always recommended in very young children, to promote positive outcomes during childhood and later adulthood. The knowledge paediatricians acquire about orofacial growth may enhance the implementation and eventual success of a preventive programme. In view of the widespread lack of any orthodontic knowledge amongst paediatricians, this paper describes most common and distinctive symptoms appearing frequently in the early stages of a child's development that are easily detectable by clinicians. It is difficult to define preventive strategies to prevent malocclusion owing to its multifactorial origin. There are some recognised behaviours, however, that should be discouraged to allow for ideal craniofacial development and some that require early referral to the orthodontist. The following disorders are easily diagnosed by the paediatrician or parents and represent conditions in which early intervention might be appropriate to prevent future possible orofacial dysfunction: different sucking habits persisting beyond 3 years of age, mouth breathing and significant deviations from established teeth eruption norms. It is suggested that early referral to a paediatric dentist or orthodontist is indicated when any of these conditions are observed. In general, measures to prevent malocclusion should be based on providing good incentives to promote normal growth and development of the face and the elimination of potential interferences that may harm these processes.

Impact of social and economic characteristics on orthodontic treatment among children and teenagers in France

OBJECTIVES

This study aimed to estimate the prevalence of orthodontic treatment in France among children and teenagers aged 8-18 years, by sex and by age, and to investigate the specific role of social and economic characteristics on use of orthodontic treatment.

METHODS

We analyzed data from the cross-sectional national health survey conducted in France in 2002-2003, which included a sample of 5988 children aged 8-18 years. All data were collected by interview including the question on orthodontic treatment. Other data used in our study were family social status and income, maternal educational attainment and place of birth, whether the child was covered by a supplementary health insurance and whether the residence was urban or rural. We also calculated the density of orthodontists in the district. Multivariate logistic regression analyses were used to study the relationships between these social and economic factors and orthodontic treatment.

RESULTS

The prevalence of orthodontic treatment was 14% of all children aged 8-18, 15% for girls, and 13% for boys, and 23% in the 12 to 15-year age group. Children were less likely to have orthodontic treatment when parents were service or sales workers compared with children whose parents were managers or professionals (aOR = 0.50; 95%CI: [0.34;0.76]), when family income was in the lowest, compared with highest quartile (aOR = 0,62; 95% CI: [0.45;0.85]), when children had no supplementary insurance compared with children covered by private insurance (aOR = 0.53; 95% CI: [0.34; 0.81]), or when they lived in rural compared with urban areas (aOR = 0.70; 95% CI: [0.54; 0.91]).

CONCLUSION

There are social inequalities in orthodontic treatment in France, associated mainly with social status, annual income, supplementary insurance, and the residence area.