The effect of early childhood non-nutritive sucking behavior including pacifiers on malocclusion: a randomized controlled trial.

BACKGROUND/RATIONALE: Systematic reviews on the effects of pacifiers on occlusion have highlighted the need for quality RCTs. TRIAL DESIGN: Single region, three parallel-armed, prospective, randomized controlled trial. OBJECTIVES: To investigate the correlations between early childhood non-nutritive sucking habits and malocclusion. Specifically to test whether the use of a study pacifier has differing effects compared to other pacifiers and control, and whether the duration of pacifier use or digit sucking influence the occlusion. PARTICIPANTS: The subjects were firstborn children, born in 2008 in Vantaa, Finland. INTERVENTION: One-third of participants were offered study pacifiers, free of charge, from birth up to 2 years of age. The history of the subjects' sucking habits, including pacifier use was screened in a questionnaire at the age of 2 years, and clinical examinations were performed at the age of 7 years. In addition, the subjects were divided into groups that were equally matched regarding their mother's level of education. OUTCOMES: Posterior crossbite, anterior crossbite, overjet, deep bite, open bite, and crowding. RANDOMIZATION METHOD: Three districts were randomly allocated to three study groups by drawing lots. BLINDING: It was not possible to blind the clinicians or parents from the intervention. Blinding during data analysis was performed. RESULTS: From the original cohort of 2715 children born in the town of Vantaa, 1911 were excluded and 353 were lost to follow-up. The remaining 451 children were divided into three groups according to the use of pacifiers. The prevalence of posterior crossbite at the age of 7 years was higher if a non-study pacifier had been used (P = .005) even when matched for the mother's level of education (P = .029). The prevalence of posterior crossbite was higher if the pacifier habit had continued for 12 months or more compared to 11 months or less, 7% and 1%, respectively, (P = .003). Digit sucking for 12 months or more was associated with crowding (P = .016). The prevalence of crossbite in the study pacifier group was less than in control pacifiers. HARMS: No adverse harms were reported other than effects on the dentition. CONCLUSION: The use of pacifiers is associated with the posterior crossbite, especially if their use continues for a year or more. Parents/guardians should be advised to stop the use or reduce the use of pacifiers to a minimum after their child's first birthday. TRIAL REGISTRATION: ClinicalTrials.gov NCT01854502.

Temporomandibular joint and Giant Panda's (Ailuropoda melanoleuca) adaptation to bamboo diet.

Here, we present new evidence that evolutionary adaptation of the Ailuripodinae lineage to bamboo diet has taken place by morphological adaptations in the masticatory system. The giant panda in the wild and in captivity removes without an exception the outer skin of all bamboo shoots, rich in abrasive and toxic compounds, by the highly adapted premolars P3 and P4. The temporomandibular joint (TMJ) allows sidewise movement of the jaw and the premolars can, in a cusp-to-cusp position, remove the poorly digestible outer skin of the bamboo before crushing the bamboo with molars. Based on the evidence presented here, we suggest that adaptation of TMJ to lateral movement for enabling cusp-to-cusp contact of premolars is the crucial evolutionary factor as which we consider the key to understand the Ailuropodinae lineage adaptive pathway to utilize the bamboo resource.

Class II treatment in early mixed dentition with the eruption guidance appliance: effects and long-term stability.

OBJECTIVES: Our aim was to analyse dentoskeletal effects and long-term stability of Class II treatment carried out with an eruption guidance appliance (EGA) in early mixed dentition. MATERIALS AND METHODS: Sixty-five Class II patients (38 females and 27 males), treated with an EGA in early mixed dentition, were compared with 58 children (26 females and 32 males) with untreated Class II malocclusion. The mean age in the treatment group at the start (T1) and end of treatment (T2) was 5.4 years (±0.4) and 8.5 years (±0.9), respectively, and at the final examination in the early permanent dentition (T3) 16.7 years (±0.4). In the control group, the mean age at T1 and T2 were 5.1 years (±0.5) and 8.4 years (±0.5), respectively. The independent and dependent sample t-tests, Chi-square test, and Fisher's test were used in the statistical evaluation. RESULTS: In the treatment group, the frequency of Class II decreased from 100 to 14% during the treatment (T1-T2) and a significant correction took place in all occlusal variables. At T2, the treatment and control groups showed statistically significant differences (P < 0.05) in all occlusal variables. In the treated children, mandibular length increased 5 mm more (P < 0.001) from T1 to T2 compared to the control children, and the ANB angle became significantly smaller (P = 0.006). During the post-treatment period (T2-T3), the frequency of Class II in the treatment group decreased from 14 to 2% (P < 0.05), overbite increased from 2.2 to 3.1 mm (P < 0.05), and lower crowding increased from 2to 14% (P < 0.05). Post-treatment changes in overjet and upper crowding were not statistically significant. At T3, the mean values of the SNA, SNB, and ANB angles were 83.0° (SD 3.9°), 81.3° (SD 3.8°), and 2.4° (SD 1.5°), respectively. CONCLUSIONS: A clinically significant correction of the molar relationship, overjet, overbite, incisor alignment, and growth enhancement of the mandible were observed after treatment in early mixed dentition. The treatment results remained largely stable in the early permanent dentition. However, an increase was observed in overbite and lower crowding. None of the children treated in early mixed dentition needed a second treatment phase.

Light-curing of orthodontic bracket adhesive by transillumination through dentine and enamel.

Bonding properties of light-curing adhesive cured by transillumination through the tooth were compared to those achieved by the conventional technique. The study analyzed the degree of cure (DC%), debonding force (DF) and adhesive remnant index (ARI) when light was transmitted through dental hard tissues. Slices of dentin and enamel of 1 mm in thickness were combined with total thicknesses of 3 or 4 mm to simulate tooth structure without the pulp tissue. DC% with curing time of 20 s, 40 s and 60 s and irradiance power was measured for each group (n = 5). Brackets were bonded using transillumination on extracted incisors (n = 6) and premolars (n = 10), and DF was measured and ARI was scored. No statistical difference was found in light transmission between the simulated samples and incisors (p > .05). Increasing the curing time from 40 s to 60 s enhanced the DC% only in premolars (p < .05). An adequate DF was achieved through transillumination both in incisors and premolars, but in premolars, the DC% remained low compared to conventionally cured brackets. Most of the bracket failures resulted from weak bracket-adhesive bond.

Priming and bonding metal, ceramic and polycarbonate brackets.

Objective: To investigate if primers can be used to modify bonding characteristics of orthodontic brackets. Materials and methods: Stainless steel, zirconia-alumina ceramic and polycarbonate brackets were bonded to enamel with and without universal and bracket material specific primers on the bracket base. Orthodontic adhesive cement (Transbond™XT) was used for bonding. The primers in each group (n = 10) were silane based (RelyX™ Ceramic Primer) and universal primer (Monobond Plus) for ceramic and metal brackets, and adhesive resin (Adper™ Scotchbond™ Multi-Purpose Adhesive) and composite primer (GC Composite Primer) for polycarbonate brackets. Controls with no primer were used for all bracket types. Teeth with bonded brackets were stored in distilled water in 37 °C for 7 days and debonded with static shear loading. Debonding forces were recorded and analyzed with ANOVA. Adhesive remnant index (ARI) was determined and enamel damage examined. Results: The bond strength without primers was 8.14 MPa (±1.49) for metal, 21.9 MPa (±3.55) for ceramic and 10.47 MPa (±2.11) for polycarbonate brackets (p < .05). Using silane as primer increased the bond strength of ceramic brackets significantly to 26.45 MPa (±5.00) (p < .05). ARI-scores were mostly 2-3 (>50% of the adhesive left on the enamel after debonding), except with silane and ceramic brackets, ARI-score was mostly 0-1 (>50% of the adhesive left on the bracket). Debonding caused fractured enamel in four specimens with ceramic brackets. Conclusions: Bond strength was highest for ceramic brackets. Silane primer increased bond strength when used with ceramic brackets leading to enamel fractures, but otherwise primers had only minor effect on the bond strength values.

Creep Behavior of Resin Composite Interface Between Orthodontic Brackets and Enamel.

PURPOSE: The present study investigated the creep of adhesive resin under constant loading at the orthodontic bracket/enamel interface with an orthodontic bracket-tooth model (shear creep) and three-point bending test (bending creep). MATERIALS AND METHODS: For the bracket-tooth model, sixty premolars were assigned to 4 groups (n = 15). Orthodontic brackets were bonded onto the enamel surface using four different bonding agents: conventional, homogeneous Transbond XT orthodontic composite (group 1/TBC); Transbond XT composite reinforced with photopolymerized glass-fiber-reinforced composite (FRC with bidirectional fibers) (group 2/TBE); Transbond XT reinforced with FRC of vertically oriented unidirectional fibers (group 3/TBV); and Transbond XT reinforced with FRC of horizontally oriented fibers (group 4/TBH). Load was applied at the bracket/tooth interface and from the bracket wire slot. In the three-point bending test, the creep and recovery of the rectangular interface materials were tested by a dynamic mechanical analyzer. The data obtained were statistically analyzed with ANOVA and a post-hoc test using SPSS v20 statistical software. RESULTS: The groups exhibited significant differences in strain % and time for bracket deflection at the interface (p < 0.05). The interface loading with unidirectional fibers (groups TBV and TBH) were statistically significantly different compared to the interface with bidirectional fibers and control group (groups TBE and TBC). The three-point test showed the least creep compliance (ie, creep deformation occurring at each time point [J]) with group TBC, followed by groups TBV and TBE. Group TBC showed the highest nanohardness and elastic modulus; the lowest values were seen in group TBE, reflecting differences in polymer matrix composition. CONCLUSION: The creep and time for debonding the bracket increased with incorporation of glass fibers at the interface between bracket and enamel.

An analysis of residual orthodontic treatment need in municipal health centres.

OBJECTIVE: The aim of this study was to analyse residual orthodontic treatment need in Finnish municipal health centres. SUBJECTS AND METHODS: A random sample of two age groups, 16- and 18-year-olds (n = 2212), from seven municipalities was invited for a clinical examination, and 1041 adolescents participated. Two calibrated orthodontists blindly examined the participants for residual treatment need, applying the Dental Health Component (DHC) and Aesthetic Component (AC) of the Index of Orthodontic Treatment Need. Self-perceived treatment need, satisfaction with occlusal function, and dental appearance were evaluated with a questionnaire. Differences between objective and self-perceived treatment need and between treated and untreated adolescents were analysed using the chi-square test. RESULTS: A total of 18.8 per cent of all adolescents had DHC grade 4 or 5 and/or AC category 8-10, indicating a definite need for treatment. In the analysis between treated and untreated adolescents, orthodontic treatment history or gender had no statistically significant association with the objectively defined need (P > 0.05). Self-perceived treatment need was reported by 9.6 per cent of adolescents. This need was more common among treated (13.9 per cent) than untreated (4.6 per cent) adolescents (P < 0.001). Among all adolescents, satisfaction with occlusal function was high, 91.3 per cent; 78.9 per cent of adolescents were satisfied with their dental appearance. The main reasons for dissatisfaction and self-perceived need were visible contact point displacements. CONCLUSIONS: The observed proportion of residual orthodontic treatment need is in line with earlier findings. The high satisfaction with occlusal function reflects the applied selection criteria; orthodontic treatment of displacements causing only aesthetic concern is not prioritized.

Acceptability of adolescents' occlusion in Finnish municipal health centres with differing timing of orthodontic treatment.

The objective of the study was to compare the acceptability of occlusion among orthodontically treated and untreated adolescents in eight Finnish municipal health centres applying different timing of treatment. A random sample of 16- and 18-year olds (n = 2325) living in these municipalities was invited for a clinical examination, and 1109 adolescents participated. Two calibrated orthodontists blindly examined the participants for the acceptability of occlusion with the Occlusal Morphology and Function Index. The history of orthodontic treatment was elicited by questionnaire. The impact of the history and timing of treatment on the acceptability of occlusion was analysed with logistic regression analysis. The history of orthodontic treatment decreased the odds for acceptability of morphology [odds ratio (OR) = 0.719, 95 per cent confidence limit (CL), P = 0.016] and acceptability of function (OR = 0.724, 95 per cent CL, P = 0.018). The early timing of treatment increased the odds for acceptability of morphology (OR = 1.370, 95 per cent CL, P = 0.042) and of function (OR = 1.420, 95 per cent CL, P = 0.023). No substantial differences were observed in the acceptability of occlusion between the early and late timing health centres. However, the proportion of subjects with acceptable occlusion was slightly higher in the early than in the late timing group. These findings suggest that when examining the effect of timing on treatment outcome, factors other than acceptability of occlusion should be concomitantly evaluated. Consequently, in this context, the duration and cost of treatment need to be investigated.

Acceptability of dental appearance in a group of Finnish 16- to 25-year-olds.

OBJECTIVE: To define a grade in the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) that would differentiate between esthetically acceptable and unacceptable occlusions and that would also be both subjectively and objectively meaningful. MATERIALS AND METHODS: Dental appearance and self-perceived orthodontic treatment need were analyzed in a group of Finnish young adults (171 males, 263 females, age range 16-25 years). Subjective data were gathered using a questionnaire, and the respondents were requested to score their dental appearance on a visual analog type 10-grade scale. Professional assessment of dental appearance was performed by two orthodontists using the AC of the IOTN. The cutoff value between esthetically acceptable and unacceptable occlusions was defined using receiver operating characteristic curves. RESULTS: Sixty-six percent of orthodontically treated and 74% of the untreated respondents were satisfied with their own dental appearance. Every third respondent reported one or more disturbing traits in their dentition. The most frequently expressed reason for dissatisfaction was crowding; girls expressed dissatisfaction more often than boys did (P = .005). A self-perceived treatment need was reported infrequently by 8% of orthodontically treated and 6% of untreated respondents. In the logistic regression analysis, self-perceived need for orthodontic treatment was the only significant factor explaining dissatisfaction with own dental esthetics. On the applied scales, grades 1 and 2 fulfilled the criteria for satisfactory dental esthetics. CONCLUSION: The results suggest that the AC grade 3 could serve as a cutoff value between esthetically acceptable and unacceptable occlusions.

Enhanced degree of monomer conversion of orthodontic adhesives using a glass-fiber layer under the bracket.

OBJECTIVE: To test the hypothesis that there is no difference in the degree of conversion (DC%) of orthodontic composites during the light-curing process with or without the use of a glass-fiber reinforcement. MATERIALS AND METHODS: Two light-curing orthodontic adhesives, Transbond XT (TB) and Beauty Ortho Bond (BO), were used with woven preimpregnated glass fibers. The degree of monomer conversion was determined for both adhesives in three settings (n = 5 per group): in the first group, the adhesive was cured without a bracket (control); in the second group, the bracket was bonded using adhesive without fiber reinforcement; and in the third group, a layer of glass-fiber net was added between the bracket and resin. The adhesive resin was light cured, and the DC% was determined by Fourier transform infrared spectroscopy. RESULTS: A two-way analysis of variance revealed significant differences in the DC% (P < .001) between adhesives and between the fiber-reinforced and nonreinforced groups. When the nonreinforced adhesives were light cured under the brackets, the DC% was significantly lower (TB: 37.0%, SD 3.4; BO: 36.9%, SD 1.9) compared with the control (TB: 54.7%, SD 0.6; BO: 65.9%, SD 0.5). A higher DC% was found when the resin was light cured in the presence of a glass-fiber net (TB: 44.1%, SD 0.3; BO: 55.3%, SD 1.7). CONCLUSION: The hypothesis is rejected. The degree of monomer conversion of the light-curing adhesive resin under stainless steel bracket can be improved by adding a thin layer of glass-fiber-reinforced composite between the bracket and adhesive resin.

Trends in finnish public orthodontic care from the professionals' perspective.

The study maps out orthodontic care in Finnish municipal health centres in 2001, describes changes during the previous ten years reported by chief dental officers, and assesses the views of orthodontists on current public orthodontic services. The data were collected by questionnaires sent to all health centres and all orthodontists in Finland. Of all 0-18-year-olds, 11% were receiving orthodontic treatment with an appliance (range 2-43% among the health centres). The most frequently used appliances were headgear, quadhelix, and fixed appliances. Limited economic resources and the lack of orthodontic expertise were mentioned by the chief dental officers as factors decreasing the volume of services. The orthodontists mentioned the large regional variation and the lack of national guidelines as the most important aspects that should be improved on a national basis. To bring about improvement, they suggested increasing the number of specialist orthodontists and the delegation of orthodontic tasks to auxiliaries.

Treated enamel surface patterns associated with five orthodontic adhesive systems--surface morphology and shear bond strength.

The chief aim of this study was to evaluate the influence of three different types of pretreatment solutions (phosphoric acid, self-etching primers, and polyacrylic acid) on enamel surfaced when used in association with one of the five orthodontic adhesive systems. In the same vein, the shear bond strength of orthodontic metal brackets was also measured to evaluate the influence of bonding procedure. After the enamel surfaces of extracted human maxillary incisors were pretreated with the five adhesive systems, scanning electron microscopy (SEM) was used to observe the effects of pretreatment on enamel. Additionally, the shear bond strength of metal brackets bonded with the five adhesives was measured (n=6). SEM observation revealed different etching patterns on the enamel surface after pretreatment. As for shear bond strength, no statistically significant differences were observed among the five different adhesives (p>0.05). It was found that self-etching primers and polyacrylic acid produced a less aggressive etching pattern than phosphoric acid. Nonetheless, all the five adhesive systems provided acceptable bond strength and attachment of orthodontic brackets.

Orthodontic intervention in the early mixed dentition: a prospective, controlled study on the effects of the eruption guidance appliance.

INTRODUCTION: A prospective, controlled cohort study was started in 1998 to investigate the effects of orthodontic treatment in the early mixed dentition with the eruption guidance appliance. METHODS: Occlusal changes were recorded in 167 treated children and 104 controls after they had reached the middle mixed-dentition stage. Treatment began when the first deciduous incisor was exfoliated (T1) and ended when all permanent incisors and first molars were fully erupted (T2). The children's mean ages were 5.1 years (SD 0.5) at T1 and 8.4 years (SD 0.5) at T2. RESULTS: From T1 to T2, overjet in the treatment group decreased from 3.1 to 1.9 mm and overbite from 3.2 to 2.1 mm. In the control group, overjet increased from 2.9 to 4.1 mm and overbite from 3.3 to 4.1 mm. At T2, the differences between the groups were highly significant (P <.001). At T1, 18% of the children in the treatment group and 22% of the controls had tooth-to-tooth contact between the maxillary and mandibular incisors. All others had an open bite, or the mandibular incisors were in contact with the palatal gingiva. At T2, tooth-to-tooth contact was observed in 99% of the treated children and 24% of the controls (P <.001). Almost half of children in both groups showed incisor crowding at T1. Good alignment of the incisors was observed in 98% of the treated children at T2, whereas maxillary crowding was found in 32% and mandibular crowding in 47% of the controls (P <.001). At T1, 41% of the children in the treatment group and 53% of the controls had a Class I relationship; the rest had either a unilateral or a bilateral Class II relationship. At T2, a Class I relationship was found in 90% of the treated children and 48% of the controls (P <.001). At least 1 occlusal deviation, including overjet > or =5 mm, overbite > or =5 mm, open bite, gingival contact of the mandibular incisors, crowding, or Class II relationship, was observed in 13% of the treated children, but the deviations were mild, and no child was considered to need treatment. In the control group, 88% of the children showed at least 1 occlusal deviation (P <.001). CONCLUSIONS: Treatment in the early mixed dentition with the eruption guidance appliance is an effective method to restore normal occlusion and eliminate the need for further orthodontic treatment. Only a few spontaneous corrective changes can be expected without active intervention.

Dentofacial changes after orthodontic intervention with eruption guidance appliance in the early mixed dentition.

OBJECTIVE: To evaluate skeletal and dentoalveolar changes induced by the eruption guidance appliance in the early mixed dentition. MATERIALS AND METHODS: Pre- and posttreatment cephalometric radiographs of 115 consecutively treated children, 62 boys and 53 girls, were compared with those obtained from a control group of 104 children, 52 boys and 52 girls. Pretreatment radiographs were taken at the deciduous-mixed dentition interphase (T1) and after full eruption of all permanent incisors and first molars (T2). The mean age of the children in both groups was 5.1 years at T1 and 8.4 years at T2. RESULTS: A significant difference between the groups at T2 was found in the mandibular length, midfacial length, and maxillomandibular differential. The increase in mandibular length was 11.1 mm in the treatment group and 7.2 mm in the control group. No differences were found in measurements of maxillary position or size. There was a significant shift toward a Class I relationship in the treatment group. Labial tipping and linear protrusion of the mandibular incisors was evident in the treatment group at T2. There was no effect on the inclination or position of the maxillary incisors. CONCLUSIONS: Occlusal correction was achieved mainly through changes in the dentoalveolar region of the mandible. In addition, the appliance enhanced condylar growth resulting in a clinically significant increase in mandibular length. No effect was observed on maxillary position, maxillary size, inclination or protrusion of the maxillary incisors, or facial height.

Orthodontists' views on indications for and timing of orthodontic treatment in Finnish public oral health care.

The aim of this study was to analyse the variation in the views of Finnish orthodontists on the indications for orthodontic treatment, timing of orthodontic assessment, and treatment methods used. The views were elicited by a questionnaire that was sent to all 146 specialist orthodontists under 65 years of age living in Finland in 2001. The response rate was 57 per cent. The association between an orthodontist's experience and timing of treatment was tested by Fisher's exact test. Stepwise logistic regression analysis was used to estimate the association between the demographic characteristics of orthodontists and the tendency to start Class II division I treatment early. Most orthodontists recommended that the first assessment of occlusion should be carried out before 7 years of age. A crossbite was mentioned as the most frequent indication for treatment in the primary and early mixed dentition, and a severe Class II division I malocclusion with an increased overjet as the most frequent indication in the late mixed dentition. Most respondents preferred early treatment, but there was a wide variation in the choice of appliances and in the timing of treatment of malocclusions other than crossbite and Class II malocclusions. A quadhelix, headgear, and the eruption guidance appliance were the most frequently used appliances in early treatment, with fixed appliances being most frequently used during the late mixed and permanent dentition phase. Orthodontists working full time in municipal health centres tended to prefer early treatment more often than those working part-time or outside health centres. There was no statistically significant association between an orthodontist's experience and timing of Class II division I and Class III treatment (P = 0.142 and P = 0.296, respectively). The preference for an early start in Class II division I treatment might be related to differing professional decisions, but no explaining factors could be found in the regression analysis.

Dentofacial features of children with distal occlusions, large overjets, and deepbites in the early mixed dentition.

INTRODUCTION: The aim of this investigation was to analyze craniofacial morphology in children with distal bites, large overjets, and deepbites in the early mixed dentition. METHODS: The sample comprised 486 Finnish children who are participating in an ongoing clinical trial. Cephalograms were obtained at the deciduous-mixed dentition interphase for the baseline of the trial. The mean age of the children was 5.1 years (SD, 2.6; range, 4.0-7.8 years). RESULTS: Subjects with bilateral distal steps of > or =1 mm compared with normal had long midfaces (P <.05), short and retrusive mandibles (P <.05), small maxillomandibular differentials (P <.001), convex profiles (P <.01), retrusive mandibular incisors (P <.01), and large interincisal angles (P <.001). Children with overjets of > or =4 mm had retrusive mandibles (P <.001), long maxillae and midfaces (P <.001), small maxillomandibular differentials (P <.001), convex profiles (P <.001), and protrusive maxillary and retrusive mandibular incisors (P <.001). Children with deepbites (overbites of > or =4 mm) had short and retrusive mandibles (P <.05), long midfaces (P <.001) and maxillae (P <.05), small maxillomandibular differentials (P <.001), convex profiles (P <.01), retrusive mandibular incisors (P <.001), and large interincisal angles (P <.001). No differences were found in the length of anterior cranial base, the position of maxilla relative to cranial base, lower facial height, and facial axis angle between any malocclusion group and normal children. All correlations between the occlusal and skeletal characteristics were low, suggesting only weak associations at this stage of development. CONCLUSIONS: These results indicate that the early dentofacial features of children with distal occlusions, large overjets, and deepbites differ from normal values. However, the skeletal patterns of these 3 malocclusion types showed considerable similarities, with long but neutrally positioned maxillae, retrusive mandibles, small maxillomandibular differences, convex profiles, retrusive mandibular incisors, and large interincisal angles, but normal growth directions and lower facial heights as common features.

Occurrence of malocclusion and need of orthodontic treatment in early mixed dentition.

This study analyzed the occlusions of 489 children at the onset of the mixed dentition period (mean age 5.1 years, range 4.0-7.8 years). These children participate in an ongoing clinical trial that is investigating the effects of orthodontic intervention in the early mixed dentition. The aim was to report the occlusal findings at the baseline. The frequencies of mesial step, flush terminal plane, and distal step were 19.1%, 47.8%, and 33.1%, respectively. The canine relationship was Class I in 46.1%, Class II in 52.4%, and Class III in 1.5% of the sides examined. An asymmetrical canine relationship was found in 30.1% of the children, significantly more often on the right side than on the left (P <.001). Overjet ranged from -2 to +10 mm with a mean of 2.9 mm. Overbite ranged from -5 to +8 mm with a mean of 2.8 mm. Excessive (> or =4 mm) overjet was found in 26.7% and overbite in 33.8% of the children; in 15.5% of the children, both variables were 4 mm or more. Anterior crowding was detected in the maxillary arch in 11.6% and in the mandibular arch in 38.9% of the children. Girls showed mandibular crowding more often than boys (P <.01). A posterior crossbite was found in 7.5% of the children, unilaterally in 6.4% and bilaterally in 1.1%. Scissors-bite was detected in 1.1% and an anterior crossbite in 2.2% of the children. The mean maximal opening was 40.3 mm. Joint sounds were registered in 5.2% of the children. The prevalence of malocclusion was between 67.7% and 92.7%, depending on the values of unacceptable parameters used for each occlusal characteristic.

Occlusal status in orthodontically treated and untreated adolescents.

In order to evaluate the outcome of orthodontic care, all available 16-year-old adolescents (n = 138) living within the catchment area of one Finnish health center were invited for a clinical examination. A total of 126 adolescents participated, corresponding to 79% of the whole age cohort. Of these, 47% had been treated orthodontically, 2% were still wearing appliances, and 51% were untreated. In 80% of cases, a non-extraction treatment was carried out. All occlusions were evaluated using a recently developed occlusal morphology and functional index (OMFI) based on assessment of 6 morphological and 4 functional traits which are classified applying an acceptable-non-acceptable dichotomy. The occlusal status in untreated individuals was used as a second reference in comparisons between the treated and untreated occlusions. The morphological criteria for an acceptable occlusion were met by 42% of the participants and the functional criteria by 64%. Although the treated occlusions failed to meet the criteria of morphological acceptability more often than the untreated ones (73% vs 40%), the proportions of non-acceptable occlusions were fairly high among untreated occlusions. The main reasons for non-acceptability were the failure of the canine relationship, overbite, and protrusion movement to fulfill the criteria of acceptability. Only 19% of the adolescents had occlusions classified as acceptable, both morphologically and functionally. In the evaluated health center, the allocation of resources resulted in a high coverage of orthodontic care. However, our results indicate that the general occlusal status in the examined age cohort did not reach an optimal level.

Selection of criteria for assessment of occlusal acceptability.

There is no general agreement on criteria that could be applied to distinguish between orthodontically acceptable and non-acceptable occlusions after the completion of dental development. The aim of the present study was to analyse morphological and functional features that could be used as an index to define an acceptable occlusion in young adults. Three expert panels representing specialists in orthodontics and stomatognathic physiology participated in a modified Delphi method. Each panel responded to a questionnaire concerning the usefulness of various occlusal features, and a set of characteristics was selected on the basis of the responses; thereafter, applicability of the chosen characteristics and their cut-offs for an acceptable non-acceptable dichotomy was tested clinically. To obtain a consensus level of 100%, the last panel session was completed with a group discussion. Assessments made using the morphological criteria were compared with those made with the dental health component of the Index of Orthodontic Treatment Need. The selected morphological characteristics consisted of overjet, overbite, canine relationship, crossbite, scissors bite and midline deviation. The functional evaluation comprised assessments of discrepancy between the centric relation and the intercuspal position, working- and non-working-side contacts and protrusion contacts. The dental health component and our morphological criteria showed different sensitivity to contact point displacements, interdigitation in buccal segments and increased overbite. This study provides a set of morphological and functional indicators reflecting the current consensus opinion of Finnish professionals. Further studies are needed to analyse the reproducibility of assessment of the characteristics included.

Reproducibility of characteristics assessing the occlusion of young adults.

The aim of the present investigation was to analyze the reproducibility in the assessment of six morphological and three functional characteristics included in a new method evaluating the occlusion in young adults. These characteristics comprised coincidence of midlines, overjet, overbite, canine relationship, crossbite, scissors bite, recurrent deviation on opening, guided lateral excursions, and discrepancy between the centric relation and the intercuspal position. The study was conducted in three stages: (1) five observers assessed the occlusions of five volunteers, (2) seven observers assessed nine volunteers, and (3) five observers assessed nine volunteers. Two calibrated orthodontists were used as references. For numerical variables, the nonparametric method for repeated measurements (Friedman's test) was used to test the significance of differences, while the proportion of agreement was calculated for categorical assessments. The results were analyzed using two precision levels: within a measurement unit/the same category and an acceptable/nonacceptable dichotomy. The magnitude of systematic differences was small and of minor clinical importance except in measurements of recurrent deviation on opening. The proportional agreement for acceptance was good in the assessment of overjet, coincidence of midlines, crossbite, scissors bite, open bite, and discrepancy between the centric relation and the intercuspal position. Moderate agreement was achieved in the assessment of overbite, canine relationship, recurrent deviation on opening, and guided lateral excursions. Among the nonacceptable cases, the agreement ranged from poor to good. The results indicated that noncalibrated observers assess categorical characteristics inconsistently.