Effect of orthodontic space closure on dental pulp sensitivity. Prospective clinical trial

BACKGROUND

Orthodontic tooth movement (OTM) is a biological process that can influence the function of the pulp, including its innervation. The excitability of the nerve fibres of the pulp may be altered by forces exerted on the nerve fibres or by reduced blood flow to the pulp. The aim of this clinical study was to evaluate the sensitivity of the dental pulp during levelling and during the phase of space closure, to assess the role of certain controlled risk factors.

METHODS

Twenty-two adolescent participants requiring orthodontic space closure in transcanine sector were enrolled in a prospective clinical study. Patients were observed before OTM, after levelling and 1 month during active space closure. The sensitivity threshold of the pulp was measured using the electric pulp test (EPT). Dental models were obtained using an intraoral scanner, allowing measurement of interdental distances and calculation of OTM speed. The teeth were categorized according to position and tooth type.

RESULTS

The EPT values increased significantly during orthodontic treatment (one-way RM-ANOVA, P = .014). There was a significant difference in EPT values between the tooth categories. Teeth with a single root adjacent to the residual space had the highest EPT thresholds (two-way RM-ANOVA, P < .001; Holm-Sidak, P < .05).

CONCLUSIONS

OTM reduced pulpal sensitivity. Pulpal sensitivity during active space closure was similar to sensitivity during the levelling phase. The pulpal sensitivity of molars was less affected by OTM than that of single-rooted teeth, while teeth closer to the gap had a significantly higher pulpal sensitivity threshold during active OTM.

The effect of orthodontic tooth movement on the sensitivity of dental pulp: A systematic review and meta-analysis

Objectives

Orthodontic tooth movement (OTM) is a process that's initiated by orthodontic forces. As a consequence, the forces could restrict pulpal blood supply, possibly affecting dental pulp. The study aimed to review the available evidence on the short and long-term effects of orthodontic tooth movement on dental pulp sensitivity and to identify clinically relevant risk factors.

Sources

PubMed, Embase, Scopus, and Web of Science were searched for papers from 1990 to the end of December 2021.

Study selection

The studies that evaluated dental pulp sensitivity of teeth undergoing OTM were included in the systematic review. Randomized, nonrandomized and case-controlled studies were included in the analysis. Risk of bias in each study was assessed using the ROBINS-I tool.

Data

The systematic search yielded an initial sample of 1110 studies, 17 were included in qualitative analysis. Most studies were classified as moderate risk of bias, however only limited long-term evidence with a higher risk of bias exists. Electric pulp test (EPT) sensitivity threshold during active OTM was increased by 4.25 SD (P < 0.001) and the relative risk (RR) of pulpal non-sensitivity was 13.27 (P < 0.001) higher compared to pre-orthodontic baseline status. Significant differences were between subgroups associated with the type of OTM. A positive relationship between pulpal non-sensitivity and mean patient age was discovered (P = 0.041). After OTM the risk of pulpal non-sensitivity remained 5.76 times higher (P < 0.001) in the long term.

Conclusions

Evidence showed that OTM could affect dental pulp sensitivity. The type of OTM and patients' age were identified as clinically relevant risk factors.

Clinical significance

Orthodontic tooth movement negatively impacts the sensitivity of dental pulp during active treatment and to a lesser degree in the long term. Pulpal sensitivity tests during active OTM should therefore be interpreted with caution. Data indicates younger patients have a lower risk of negative pulpal sensitivity during orthodontic treatment.

Three-dimensional evaluation of the association between face and back asymmetry among pre-pubertal subjects

AIM

The aim was to compare the degree of back symmetry in two groups of subjects with and without pathologic facial asymmetry and to assess any possible associations between face and back asymmetry evaluated on three-dimensional surface face and back scans.

MATERIALS AND METHODS

The study design consisted of allocation of 70 subjects (35 females, 35 males) aged 6.4±0.5 years, according to the percentage of whole face symmetry assessed on three-dimensional (3D) facial scans into a 'symmetric' (symG; symmetry ≥70%) and 'asymmetric'(asymG; symmetry <70%). The 3D face and back scans were analysed using colour deviation maps and percentages of symmetry of the whole face and back surfaces as well as their three separate areas: forehead, maxillary and mandibular areas for the face and neck, upper and middle trunk areas for the back, were calculated. Non-parametric statistical tests were used for between-group comparisons (Mann-Whitney U test). Within each group, differences between each face or back area were tested with the Friedman test. Correlations between face and back symmetry were assessed with the Spearman rho coefficient.

RESULTS

The symG exhibited a significantly higher symmetry in each facial area than the asymG. The mandibular area was the least symmetric area of the face within each group, with significantly smaller values than the maxillary area in the symG and significantly smaller values than the forehead and maxillary area in the asymG. The percentage of whole back symmetry did not significantly differ (p>0.05) between the symG ( 82.00% [67.4;88.00]) and asymG (74.3% [66.1;79.6]). The only significant between-group difference was observed for the symmetry of the upper trunk area (p=0.021), with lower symmetry values in the asymG. No significant associations were detected between face and back parameters.

CONCLUSION

The percentages of symmetry in each facial area were significantly higher among subjects without pathologic facial asymmetry. The most asymmetric area of the face, regardless of the degree of whole face symmetry, was its mandibular area. No significant differences were detected within different back areas; however, subjects with asymmetric faces showed significantly smaller symmetry of their upper trunk area.

Three-dimensional assessment of palatal area changes after posterior crossbite correction with tooth-borne and tooth bone-borne rapid maxillary expansion

OBJECTIVES

To assess and compare the three-dimensional treatment changes in palatal surface area and volume using either tooth-borne (TB) or tooth bone-borne (TBB) rapid maxillary expanders and to evaluate the long-term effects of the two devices and the incidence of the relapse between the groups.

MATERIALS AND METHODS

A total of 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (standard deviation [SD], 1.3), or the TBB group, mean age 9.5 years (SD, 1.2). Study casts were taken before, directly after, 1 year after, and 5 years after expansion. Study casts were digitized, superimposed, and evaluated. Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio.

RESULTS

Changes in palatal volume, palatal surface area, and palatal projection area within and between the groups up to 5 years after expansion followed the same pattern and did not show any statistically significant differences between the groups. Relapse was seen in 15% of the patients. It seemed that open-bite and a Class III growth pattern could be assumed as prognosis-deteriorating factors in regard to stability of the treatment.

CONCLUSIONS

There were no significant differences between the TB and TBB groups in palatal volume, palatal shell area, or palatal projection area directly after expansion or at 1 year and 5 years after expansion, which implies that the two devices gave rise to the same immediate and long-term outcomes.

The Use of Magnetic Resonance Imaging in Diagnostics of Radix Paramolaris: A Case Report

Background and Objectives:

This case report aims to present a rare morphological variation of Radix Paramolaris (RP) diagnosed using Magnetic Resonance Imaging (MRI) to discuss its morphological associations and possible implications on dental treatment. Radix paramolaris is a buccally located supernumerary root of the permanent mandibular molars. It is very rare in the European population, with a prevalence below 4%.

Case Presentation:

A 7-year-old boy with severe Class II malocclusion is presented. The first phase of orthodontic treatment consisted of therapy with a removable activator appliance. Before the second phase of treatment, unilateral radix paramolaris on the second right permanent mandibular molar was discovered.

Results:

Supernumerary root was diagnosed using a 3T whole-body MRI system. This case confirmed the association between supernumerary roots and increased buccal crown cusps in a mandibular molar. Furthermore, it demonstrated the effectiveness of non-invasive MRI as a complementary diagnostic tool, offering clear advantages in diagnosing rare morphological variations such as supernumerary roots. Unlike conventional radiography, MRI is able to distinguish the soft tissues, including the dental pulp, and does not emit ionizing radiation.

Conclusion:

To diagnose a supernumerary root and the state of its pulpal tissue, a precise radiographic and clinical examination is required since awareness of exact root morphology can be of paramount importance in clinical decision-making for several dental procedures.

Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials

Hyposalivation is a condition represented by a reduced salivary flow and may include symptoms such as mouth dryness (xerostomia), loss of taste, pain, dysphagia, and dysphonia, all of which greatly affect an individual's quality of life.The aim of the present study was to systematically review the effects of low-level light therapy irradiation (photobiomodulation) on salivary gland function in patients with hyposalivation.The main question of the systematic review was: "Does low-level light irradiation therapy of the salivary glands affect salivary flow rate or indicators of salivary function (ion and protein concentrations) in patients with xerostomia or hyposalivation?" The question was based on the PICO (participant, intervention, control, outcome) principle and followed the PRISMA guidelines. Databases were explored and papers published between the years 1997 and 2020 were reviewed for the following Mesh-term keywords and their corresponding entry terms in different combinations: "Low-level light therapy," "Xerostomia," "Saliva," "Salivary glands," "Salivation."The initial sample consisted of 220 articles. Of those, 47 articles were used for full-text analysis and 18 were used for a systematic review, 14 were used in meta-analysis. According to their individual quality, most articles were classified as high quality of evidence according to the GRADE score. Meta-analysis of the evidence observed increase of unstimulated salivary flow 0.51 SMD compared to placebo (95% CI: 0.16-0.86), I² = 50%, p = 0.005.The findings of our review revealed evidence of a beneficial effect of photobiomodulation therapy on salivary gland function. The therapy alleviates xerostomia and hyposalivation. However, these effects are reported short term only and did not induce lasting effects of photobiomodulation therapy on patients' quality of life.

Comparison Between Accuracy of Posts Fabricated Using a Digital CAD/CAM Technique and a Conventional Direct Technique

PURPOSE

To compare the accuracy of posts fabricated using a conventional direct technique with casting to the accuracy of posts fabricated using a fully digital protocol with CAD/CAM technology and selective laser melting.

MATERIALS AND METHODS

Ten extracted permanent maxillary incisors were endodontically treated and prepared for a post. For each tooth, two metal posts were fabricated, one by casting (Group C) and one by a fully digital protocol (Group D). Accuracy of fit was analyzed with computed microtomography (μCT) to compare the space volume, the space area, and the distance between the post and the prepared root canal wall among posts.

RESULTS

The mean and SD values of the overall space volume and the distance between the post and the prepared root canal wall, respectively, were: Group C: 2.22 ± 1.35 mm³ and 53.66 ± 23.39 μm; Group D: 3.82 ± 0.45 mm³ and 89.47 ± 19.30 μm. The values for the Group C posts were significantly lower (P = .002). All space volume values in all measured sections were significantly lower for the Group C posts. The mean distance and the space area between the post and the prepared root canal wall in the apical sections 3 (P < .001 for both) and 4 (P = .0019; P = .004, respectively) were significantly lower in Group C. No significant differences were calculated in cervical sections 1 and 2.

CONCLUSION

Both methods of post manufacturing were similarly accurate in the cervical part of the prepared root canal; however, a significant difference regarding the accuracy of both methods was determined for the apical parts of the posts.

Three-dimensional evaluation of forced unilateral posterior crossbite correction in the mixed dentition: a randomized controlled trial

Objectives

The objectives of this study were to assess the three-dimensional (3D) treatment changes (palatal surface area and volume) of forced unilateral posterior crossbite correction using either quad-helix or removable expansion plate appliances in the mixed dentition, and to compare the treatment changes with the three-dimensional changes occurring in age-matched untreated unilateral posterior crossbite patients as well as in subjects with normal occlusion and with no or mild orthodontic treatment need.

Trial design

Six-arm parallel group multicentre randomized controlled trial.

Materials and methods

One-hundred and thirty-five patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 25, and the patients were randomized into the following five groups: quad-helix treatments in specialist orthodontic clinics (QHS), quad-helix treatments in general dentistry (QHG), removable expansion plate treatments in specialist orthodontic clinics (EPS), removable expansion plate treatments in general dentistry (EPG), and untreated crossbite (UC). Twenty-five patients with normal occlusion who served as normal controls were also included in the trial. Blinding of the outcome assessor and data analyst was accomplished. Data on all children were evaluated on an intention-to-treat basis, regarding 3D palatal surface area, palatal projection area, and palatal shell volume; two-dimensional linear measurements were registered at the same time.

Results

After treatment, the surface and projection area and shell volume increased in the four treatment groups (QHS, QHG, EPS, and EPG). QHS increased significantly more than EPG for the surface and projection area. The QHS and EPS had significantly higher mean difference for shell volume.

Limitations

The trial considers a short-term evaluation.

Conclusion

After treatment, there were no significant differences between the four treatment groups and the normal group, which implies that the surface and projection area together with the shell volume for the four treatment groups and the normal group were equivalent.

Trial registration

The trial was registered with https://www.researchweb.org/is/sverige, registration number: 220751.

Three-dimensional assessment of back symmetry in subjects with unilateral functional crossbite during the pre-pubertal growth phase: a controlled study

BACKGROUND/OBJECTIVES

Since a high prevalence of back anomalies has been reported among subjects with crossbite, the aim was to assess the degree of back symmetry among subjects with (crossbite) and without (control) unilateral functional crossbite during the pre-pubertal growth phase.

METHODS

A group of 70 subjects (36 boys, 34 girls; 6.8 ± 1.2 years) in the primary or mixed dentition phase were included. Clinical assessment of head posture, shoulder, scapula and hip height were performed with the subject standing, and differences between the left and right side greater than 5 mm recorded. Asymmetry of the scapula and trunk prominence greater than 8 mm was recorded along with the prominence of thoracic and lumbar paravertebral musculature during the forward-bending test. Back symmetry was assessed qualitatively and quantitatively on colour deviation maps of superimposed mirrored three-dimensional back scans at a tolerance level of 2 mm.

RESULTS

No significant differences were observed between the groups regarding the frequency of clinically assessed back anomalies. The percentage of back symmetry was slightly lower in the crossbite than that in the control group (71.4 ± 13.3% and 79.2 ± 12.1%, respectively). A significant association (P < 0.05) was seen between scapula plane inclination (OR = 3.41) and scapula prominence inequalities (OR = 3.29) and unilateral functional crossbite, while hip height inequalities (OR = 0.94) were more frequent in the control group. No associations were detected between the side of crossbite and side of prominence of back parameters.

LIMITATIONS

The use of different thresholds for clinical (5-8 mm) and three-dimensional (2 mm) symmetry assessment.

CONCLUSIONS

Although some degree of back asymmetry was detected in the crossbite group during the pre-pubertal growth phase, this asymmetry does not appear to be clinically relevant.

Palatal morphology in unilateral cleft lip and palate patients: Association with infant cleft dimensions and timing of hard palate repair

OBJECTIVES

To assess the impact of cleft severity and timing of hard palate repair on palatal dimensions in unilateral cleft lip and palate (UCLP) children.

SETTING AND SAMPLE POPULATION

Single-centre analysis within a multicenter RCT of primary surgery; 122 UCLP randomized to early hard palate closure (EHPC) at 12 months or delayed hard palate closure (DHPC) at 36 months; 28 frequency-matched controls.

METHODS

Linear measurements of palatal height, width and length were performed on 116 digital models of UCLP subjects (8.21 years, SD = 0.53) and 28 models of non-cleft individuals (8.44 years SD = 0.72). Cleft dimensions at infancy (mean 1.8 months) were considered. In a pilot study, shell-to-shell distances between the 3D cleft palate objects and a reference mesh were calculated and differences between the groups assessed. Morphological differences were visualized using colour mapping.

RESULTS

Compared to controls, UCLP subjects presented a higher palate at the level of the anterior scar (P = 0.002), but generally a lower palate in the middle region (P < 0.001). Comparing UCLP subgroups, the DHPC subjects showed a flatter palate posteriorly (P = 0.048) and the EHPC group exhibited more transversal constriction (P = 0.003 at M1 level). 3D analysis revealed a shallower palate in the DHPC group both in the middle (P = 0.002) and the posterior part (P = 0.008). Anterior cleft severity correlated negatively with palatal height (P = 0.01).

CONCLUSIONS

Unilateral cleft lip and palate palates differ from controls in width and height. DHPC may represent an advantage for the transversal dimension, but a disadvantage for palatal height. Infant cleft dimensions partially explain differences in palatal height.

Nanoparticle concentrations and composition in a dental office and dental laboratory: A pilot study on the influence of working procedures

During material treatment in dentistry particles of different size are released in the air. To examine the degree of particle exposure, air scanning to dental employees was performed by the Scanning Mobility Particle Sizer. The size, shape and chemical composition of particles collected with a low-pressure impactor were determined by scanning electronic microscopy and X-ray dispersive analysis. The average concentrations of nanoparticles during working periods in a clean dental laboratory (45,000-56,000 particles/cm³), in an unclean dental laboratory (28,000-74,000 particles/cm³), and in a dental office (21,000-50,000 particles/cm³), were significantly higher compared to average concentrations during nonworking periods in the clean dental laboratory (11,000-24,000 particles/cm³), unclean laboratory (14,000-40,000 particles/cm³), and dental office (13,000-26,000 particles/cm³). Peak concentration of nanoparticles in work-intensive periods were found significantly higher (up to 773,000 particles/cm³), compared to the non-working periods (147,000 particles/cm³) and work-less intensive periods (365,000 particles/cm³). The highest mass concentration value ranged from 0.055-0.166 mg/m³. X-ray dispersive analysis confirmed the presence of carbon, potassium, oxygen, iron, aluminum, zinc, silicon, and phosphorus as integral elements of dental restorative materials in form of nanoparticle clusters, all smaller than 100 nm. We concluded that dental employees are exposed to nanoparticles in their working environment and are therefore potentially at risk for certain respiratory and systematic diseases.

Facial soft tissue changes during the pre-pubertal and pubertal growth phase: a mixed longitudinal laser-scanning study

BACKGROUND/OBJECTIVES

Facial soft tissues changes during growth roughly tend to mimic the underlying hard tissues, but not completely. The aim of this mixed longitudinal study was to assess facial growth among pre-pubertal and pubertal subjects without malocclusion using a non-invasive three-dimensional laser scanning system.

SUBJECTS/METHODS

Fifty-nine subjects (30 females and 29 males) aged at baseline 5.4-8.9 years with normal occlusion were clustered into the younger, older pre-pubertal, and pubertal groups according to age and the absence/presence of a standing height growth spurt. Three-dimensional facial images were obtained using laser scanners for five consecutive years. Several transversal, sagittal, and vertical parameters were assessed for between and within group comparisons.

RESULTS

Significant overall changes of almost all parameters were seen within each group (P < 0.05) without any group differences (P > 0.05). The younger pre-pubertal group showed greater annual growth rates of lip prominence; both pre-pubertal groups showed greater rates in facial middle third height. The pubertal group showed greater annual rates in facial profile angle changes during the growth peak.

LIMITATIONS

A high standing height increment (7cm) was used as the threshold for subject allocation in the pubertal group.

CONCLUSIONS

Soft tissue facial growth has generally similar amounts and rates irrespective of the pubertal growth spurt. Pre-pubertal subjects show greater annual rates of facial middle third height changes while pubertal subjects show greater annual rates of chin protrusion.

Diagnosis of Class III malocclusion in 7- to 8-year-old children--a 3D evaluation

OBJECTIVES

The aim of this study was to characterize facial and jaw morphology of children with Class III malocclusion in early mixed dentition.

METHODS

This study was conducted on 7- to 8-year-old Caucasian children, 48 children with Class III malocclusion and 91 children with normal occlusion. Surface images of faces and study casts were obtained using laser scanning. Two average facial templates were constructed for the males and females in the control group. The facial images were superimposed on the corresponding average templates. Facial parameters, palatal volumes, and gingival surface areas were measured and group differences were quantified. The analysis of variance was used for statistical evaluation of the measured parameters.

RESULTS

The results revealed shorter lower face height (P < 0.001), concave facial profile (P < 0.001), retruded maxilla (P < 0.001), protruded mandible (P < 0.001), retrusive mid-face restricted area (P < 0.001), reduced gingival surface area of the maxilla (P = 0.013), and reduced maxilla/mandible gingival surface area ratio (P < 0.001) in the Class III group compared to the control group. There were no differences between the groups in upper face height, restricted areas of the upper and lower face, palatal volume, and gingival surface area of the mandible (P > 0.05).

LIMITATIONS

Regardless of the fact that the prevalence of Class III malocclusion is rather small, the sample size could be larger.

CONCLUSIONS

Class III subjects show clinically relevant facial and jaws characteristics in pre-pubertal growth period. A comprehensive diagnosis should include transverse dimension analysis.

[How to push the limits in the transverse dimension? Facial asymmetry, palatal volume and tongue posture in children with unilateral posterior cross bite: a three-dimensional evaluation of early treatment]

Unilateral posterior crossbites have been reported to be one of the most prevalent malocclusions of the primary dentition in Caucasian children. Facial asymmetry due to lateral mandibular displacement in unilateral posterior crossbite, if not treated in the primary dentition period, may lead to an undesirable growth modification which results in facial asymmetry of skeletal origin. Irregular tongue function and posture have also been diagnosed as important etiological factors. Early orthodontic treatment seems to be profitable and desirable to create conditions for normal dental, functional and skeletal development of the orofacial region. Treatment success after correction of unilateral posterior crossbite in the primary dentition is highly questionable, as it is very difficult to objectively assess correction of facial asymmetry and irregular tongue function and posture in small, growing children. Although facial photography is an important diagnostic tool in orthodontics, its main disadvantage is that it represents a three dimensional subject in two dimensions. Tongue posture and function during clinical examination are difficult to assess and is therefore unreliable. Contemporary 3D diagnostics in unilateral posterior crossbite enables uninvasive, valid and objective assessment of facial morphology, palatal volume, tongue function and posture. It can, therefore, become in the future an important part of morphological and functional diagnostics in orthodontics and dentofacial orthopedics before, during and after orthodontic treatment.

A 2D ultrasound evaluation of swallowing in children with unilateral posterior crossbite

BACKGROUND

Swallowing pattern is important in the aetiology of unilateral posterior crossbite (ULCB). The aim of this study was to assess the swallowing pattern and tongue function during swallowing in children with ULCB in deciduous dentition using B-mode and M-mode ultrasonography.

MATERIALS AND METHODS

Twenty-three children with ULCB, aged 4.1-6.6 years, and 22 children without ULCB, 5.7-6.7 years, were examined with simultaneous B- and M-mode ultrasonography. The swallowing pattern was assessed according to the action of genioglossus muscle in ultrasound images with the scan line of the ultrasound transducer set through the tongue tip. The tongue movements (duration, range, and speed) were compared within each subphase (I, IIa, IIb, IIIa, and IIIb) and in the entire swallowing cycle between the children with ULCB and without ULCB.

RESULTS

The visceral swallowing pattern was found in 83 per cent of children with ULCB and in 36 per cent of children without ULCB; the difference was statistically significant. The duration of phase IIb and the entire swallowing act was found to be statistically significantly prolonged in the ULCB group. Furthermore, the range of the tongue movement in phases and in the entire swallowing act was statistically significantly larger in the ULCB group. The speed of the tongue movement was statistically significantly higher in the ULCB group in phase IIa.

CONCLUSIONS

The 2D ultrasonography was used to evaluate the prevalent type of swallowing in children with ULCB. Visceral type of swallowing pattern and the changed tongue function during swallowing seem to be important factors in the aetiology of ULCB.

A controlled study of the functional and morphological characteristics of malocclusion in prematurely born subjects with low birth weight

BACKGROUND/OBJECTIVES

Prematurely born children show significant delay in many areas of physical development, including the orofacial structures. The aim of the present study was to evaluate the influence of premature birth on the prevalence of functional and morphological characteristics of malocclusion in the deciduous dentition phase, considering also confounding variables, such as type of feeding and oral habits.

MATERIAL/METHODS

Through questionnaires and clinical examinations of 80 prematurely born subjects (42 females, 38 males, aged 24.46 ± 1.77 months; PBG) and 113 controls (50 females, 63 males, aged 25.42 ± 2.64 months; CG) in the deciduous dentition phase, data about feeding modalities, sucking habits, and functional and morphological characteristics of malocclusion were collected, and the two groups were compared for differences (chi-square test). Logistic regression analysis was used for risk assessment.

RESULTS

The prevalence of functional and morphological characteristics was not significantly different (P > 0.05) in PBG compared with the CG, and premature birth was not a risk indicator for any characteristics of malocclusion. The main significant risk indicators for class II/1 malocclusion were dummy (OR = 3.13; P < 0.01) and thumb sucking (OR = 4.41; P < 0.05), while dummy sucking alone was a risk indicator for anterior open bite (OR = 12.19; P < 0.001).

LIMITATIONS

In the present study, the PBG and CG were close in mean gestational age and birth weight, which might have influenced the results.

CONCLUSIONS

Prevalence of malocclusion among prematurely born subjects is not significantly different compared with controls, and premature birth is not a risk indicator for any functional or morphological characteristics of malocclusion.

Assessment of facial asymmetry in growing subjects with a three-dimensional laser scanning system

OBJECTIVES

To evaluate facial asymmetry in growing subjects with no malocclusion on three-dimensional laser facial scans.

SETTING AND SAMPLE POPULATION

Twenty-seven healthy Caucasian children (15 boys and 12 girls, aged 5.4 ± 0.3 years) in the primary dentition without malocclusion were randomly selected from a local kindergarten in Slovenia.

MATERIAL AND METHODS

Surface facial images were obtained using a three-dimensional laser scanning system at baseline and at 18, 30, 42 and 54 months of follow-up. Facial asymmetry was assessed quantitatively by measuring the average distance between facial image and mirrored image. Further, the percentage of asymmetry was calculated as the percentage of image to mirrored image not coinciding within 0.5 mm. Qualitative assessment was performed on colour deviation maps by recording the predominant side of the face for the upper, middle and lower parts of the face separately. Nonparametric tests were used for data analysis.

RESULTS

No face was perfectly symmetric. The average distance between the mirrored images for the whole face ranged 0.22-0.85 mm and the percentage of asymmetry 7.8-66.9. There were no significant gender differences (p > 0.05), and no significant change was found over the observed period. The upper part of the face was the least asymmetric, while the lower and middle parts showed similar degrees of asymmetry.

CONCLUSION

Facial asymmetry is already present at an early developmental stage and does not show any tendency to increase or decrease with growth in the pre-pubertal period.

Diagnostic performance of 3-dimensional evaluation of palatal vault changes in assessing successful treatment of constricted maxilla in growing subjects

INTRODUCTION

The success of maxillary expansion should not be assessed solely by the elimination of the teeth in crossbite; it should also be defined as the reestablishment of normal maxillary growth. The aim of this research was to quantify longitudinal palatal changes in children treated for maxillary constriction associated with functional crossbite.

METHODS

The subjects included 48 white children (mean age, 5.2 ± 0.6 years), divided into a treatment group (n = 23) and a control group (n = 25). Children in the treatment group had maxillary constriction associated with functional crossbite and were treated with a cemented acrylic splint expander. Dental casts were collected at baseline and at 6, 12, 18, 30, 42, and 54 months later. The casts were scanned with a laser scanner, and the palatal surface areas and volumes, and their increments over time were calculated. Nonparametric tests were used for the data analysis. The diagnostic performance in assessing successful treatment of palatal constriction was evaluated by receiver operating characteristic curves.

RESULTS

Significantly greater increments in palatal surface area and volume were seen in the treatment group up to 30 months (P <0.05, at least). According to the receiver operating characteristic curves, the best overall diagnostic performance in terms of accuracy was for palatal volume at 18 months, reaching up to a value of 0.85, by using a cutoff value of increments of 13.5%.

CONCLUSIONS

An increase in palatal volume of at least 13.5% at 18 months after treatment is a good indicator to assess the reestablishment of normal growth in subjects treated for maxillary constriction in the deciduous dentition.

Influence of sucking habits and breathing pattern on palatal constriction in unilateral posterior crossbite--a controlled study

The aim of this study was to evaluate the influence of prolonged sucking habits and mouth breathing on palatal vault morphology in a group of subjects with unilateral functional crossbite [crossbite (CB) group] compared with a group of subjects with normal occlusion [non-crossbite (NCB) group]. A sample of 80 Caucasian subjects (51 CB and 29 NCB; aged 5.3 ± 0.8 years) in the deciduous dentition was selected. A questionnaire regarding the subject's sucking habits was answered by the parents. Any sucking habit that lasted more than 24 months was considered as a prolonged sucking habit. The breathing pattern was assessed by an experienced otorinolarygologist and was classified either mainly nose or mouth breathing. Intercanine and intermolar distances and palatal surface area and volume were recorded three dimensionally on study casts. Univariate and multivariate analyses were employed. Posterior CB was negatively correlated with all the dental and palatal parameters (P < 0.01) with the exception of the palatal surface area that did not reach the statistical significance. Only prolonged sucking habits (but not mouth breathing) was a significant risk indicator for unilateral functional CB (P < 0.001). However, the prolonged sucking habits were not significantly correlated with any of the investigated parameter, and mouth breathing was negatively correlated with the intermolar distance only. Therefore, maxillary constriction in unilateral functional CB might not be influenced by the presence or absence of prolonged sucking habits or mouth breathing.

Three-dimensional evaluation of facial asymmetry in association with unilateral functional crossbite in the primary, early, and late mixed dentition phases

OBJECTIVE

To assess the degree of facial asymmetry associated with subjects with unilateral functional crossbite (CB) in the primary, early/intermediate, and late mixed dentition phases in comparison with a group of subjects without CB.

SUBJECTS AND METHODS

A group of 234 white subjects, 78 with CB (42 girls and 36 boys) and 156 without CB (73 girls and 83 boys), aged 3.9-11.9, grouped according to the dentition phase, were included. Three-dimensional laser scans of the subjects' faces were used to assess facial asymmetry. For each part of the face two-way multivariate analysis of covariance was performed to assess differences among the subjects, and an independent sample t-test was used to assess the significance of the differences between data sets.

RESULTS

  Within all dentition phases, the subjects with CB had statistically significantly greater facial asymmetry of the whole face than the subjects without CB, with the greatest values in the lower part of the face (P < .05). In the middle part of the face a significant difference was observed in the mixed dentition phases.

CONCLUSIONS

Children with unilateral functional CB exhibited a greater facial asymmetry than children without this malocclusion in all the dentition phases herein investigated. The greatest differences were seen for the lower part of the face. Further, facial asymmetry in the middle part of the face became clinically relevant in combination with the transition from primary to mixed dentition phase.

Three-dimensional evaluation of facial morphology in children aged 5-6 years with a Class III malocclusion

The aim of this study was to evaluate facial morphology in 25 Class III and 46 non-Class III children aged 5-6 years using three-dimensional (3D) laser imaging; 3D facial images were obtained, two average facial templates were constructed for the non-Class III male and female groups, each individual face was superimposed on the corresponding average template and group comparisons were evaluated (facial height, facial convexity, mandibular position and facial surface morphology). Differences between parameters were evaluated by using an analysis of variance and colour deviation maps. The results showed that Class III children had less mid-face prominence and a concave facial profile when compared to non-Class III children (P = 0.002 and P = 0.018). The position of the pg point in the z-axis just failed to reach statistical significance when comparing the two groups (P = 0.051). A vertical analysis showed no statistical significance between the groups, when evaluating middle (n-sn) and lower (sn-pg) facial height. Coincidence of the Class III faces to normal templates with a tolerance set as 0.5 mm was low (less than 30%). The soft tissue characteristics of a Class III face differ significantly from the non-Class III face in the mid-face region and in the facial profile. A 3D laser imaging method evaluated and identified morphological characteristics of Class III children in deciduous dentition, which could in the future become an important diagnostic tool in small children. The most important clinical advantage of this study is the non-invasiveness of the method.

Three-dimensional longitudinal evaluation of palatal vault changes in growing subjects

OBJECTIVE

To evaluate palatal vault change in children and to assess the reliability of two palatal parameters in assessing growth modifications.

SUBJECTS AND METHODS

A group of 26 healthy white children aged 5.3 ± 0.3 years (15 boys, 11 girls) were randomly selected. Impressions of the upper dental arches were obtained at baseline and at 12, 18, and 30 months follow-up. Three-dimensional digital images of study casts were obtained using a laser scanning device. Palatal surface area and palatal volume were measured on the digital study casts at each time point. Effect size (ES) coefficients were calculated for both parameters as indices of diagnostic reliability in individual subjects when at least equal to 1.0.

RESULTS

Significant increases in palatal surface area and volume were seen over the observation period (P < .001). ES coefficients for palatal surface area were greater than those for palatal volume. However, even for the former parameter, only the value taken at 30 months was above the threshold.

CONCLUSIONS

Growth of the palatal vault was significant during the observation period, which coincides with primary and mixed dentition stages. Palatal surface area appears to be more reliable than palatal volume in assessment of growth modifications in individual subjects.

Three-dimensional evaluation of early crossbite correction: a longitudinal study

The aim of this longitudinal study was to assess whether correction of unilateral posterior crossbite in the primary dentition results in improvement of facial symmetry and increase of palatal surface area and palatal volume. A group of 60 Caucasian children in the primary dentition, aged 5.3 ± 0.7 years, were collected at baseline. The group consisted of 30 children with a unilateral posterior crossbite with midline deviation of at least 2 mm (CB) and 30 without malocclusion (NCB). The CB group was treated using an acrylic plate expander. The children's faces and dental casts were scanned using a three-dimensional laser scanning device. Non-parametric tests were used for data analysis to assess differences over the 30 months period of follow-up. The CB children had statistically significantly greater facial asymmetry in the lower part of the face (P < 0.05) and a significantly smaller palatal volume (P < 0.05) than the NCB children at baseline. There were no statistically significant differences between the two groups at 6, 12, 18, and 30 months follow-ups. Treatment of unilateral posterior crossbite in the primary dentition period resulted in an improvement of facial symmetry in the lower part of the face (P < 0.05) and increase of the palatal surface area and palatal volume (P < 0.001). At 30 months, relapse was observed in eight children (26.7 per cent). Treatment of unilateral posterior crossbite in the primary dentition improves facial symmetry and increases the palatal surface area and the palatal volume, though it creates normal conditions for normal occlusal development and skeletal growth.

Novel method of 3-dimensional soft-tissue analysis for Class III patients

INTRODUCTION

The aim of this study was to evaluate 3-dimensional facial shells by incorporating a population-specific average template with a group of Class III subjects preparing to have orthognathic surgery.

METHODS

The Class III group included 14 male (MCIII) and 15 female (FCIII) subjects. We used 43 male and 44 female Class I subjects to construct average male (AvM) and female (AvF) faces. Coordinates of 3 points on the facial templates of groups MCIII and FCIII and the templates AvM and AvF were compared. MCIII-AvM and FCIII-AvF superimpositions were evaluated for differences.

RESULTS

Vertical distances (sella to soft-tissue pogonion) were statistically significantly higher for the AvM (9.1%) and MCIII (10.1%) than for the AvF and FCIII, respectively (P < 0.05). The distances of soft-tissue pogonion in the horizontal x-axis were positive in 80% of the FCIII group and 85.7% of the MCIII group. The Class III subjects differed from the average face in the lower two thirds, but, in 50% (MCIII) and 60% (FCIII), they differed also in the upper facial third.

CONCLUSIONS

(1) The average and Class III Slovenian male morphologic face heights are statistically significantly higher than those of the female subjects. (2) The Slovenian Class III male and female subjects tend toward a left-sided chin deviation. (3) Differences between Class III patients and a normative data set were determined.

Three-dimensional ultrasound diagnostics of tongue posture in children with unilateral posterior crossbite

INTRODUCTION

Incorrect tongue posture on the mouth floor is considered an important factor in the etiology of unilateral posterior crossbite. The aim of this study was to objectively assess tongue posture in children with unilateral posterior crossbite and those with normal deciduous dentition by using 3-dimensional (3D) ultrasonography.

METHODS

First, referential 3D ultrasound images for differently postured tongues were acquired and reconstructed in 10 adults. Second, 27 children with unilateral posterior crossbite (mean age, 5.4 ± 1 years) and 23 children with normal deciduous dentition (mean age, 6.2 ± 0.4 years) were examined by using the 3D ultrasound technique. The referential 3D ultrasound reconstructions were used for the assessment of tongue posture in each child.

RESULTS

The characteristic 3D reconstruction of the tongue postured on the palate displays distinctive convexity of the tongue dorsum, whereas, in the 3D reconstruction with the tongue postured on the mouth floor, the dorsum is characterized by a central groove and expressed concavity. Posture on the mouth floor was demonstrated by 81.5% of the children with unilateral posterior crossbite and by only 34.8% of those with normal deciduous dentition. The difference was statistically significant (Fisher exact test: P = 0.0012).

CONCLUSIONS

Three-dimensional ultrasonography enables objective assessment of tongue posture and could become in the future an important part of functional diagnostics before, during, and after orthodontic treatment.

Use of 3-dimensional surface acquisition to study facial morphology in 5 populations

INTRODUCTION

The aim of this study was to assess the use of 3-dimensional facial averages for determining morphologic differences from various population groups.

METHODS

We recruited 473 subjects from 5 populations. Three-dimensional images of the subjects were obtained in a reproducible and controlled environment with a commercially available stereo-photogrammetric camera capture system. Minolta VI-900 (Konica Minolta, Tokyo, Japan) and 3dMDface (3dMD LLC, Atlanta, Ga) systems were used. Each image was obtained as a facial mesh and orientated along a triangulated axis. All faces were overlaid, one on top of the other, and a complex mathematical algorithm was performed until average composite faces of 1 man and 1 woman were achieved for each subgroup. These average facial composites were superimposed based on a previously validated superimposition method, and the facial differences were quantified.

RESULTS

Distinct facial differences were observed among the groups. The linear differences between surface shells ranged from 0.37 to 1.00 mm for the male groups. The linear differences ranged from 0.28 and 0.87 mm for the women. The color histograms showed that the similarities in facial shells between the subgroups by sex ranged from 26.70% to 70.39% for men and 36.09% to 79.83% for women. The average linear distance from the signed color histograms for the male subgroups ranged from -6.30 to 4.44 mm. The female subgroups ranged from -6.32 to 4.25 mm.

CONCLUSIONS

Average faces can be efficiently and effectively created from a sample of 3-dimensional faces. Average faces can be used to compare differences in facial morphologies for various populations and sexes. Facial morphologic differences were greatest when totally different ethnic variations were compared. Facial morphologic similarities were present in comparable groups, but there were large variations in concentrated areas of the face.

Facial morphology of Slovenian and Welsh white populations using 3-dimensional imaging

OBJECTIVE

To use 3-dimensional (3D) facial averages to test the hypothesis that the facial morphologies of 2 European white groups (Slovenia and Wales) have no differences.

METHODS

Fifty males and 50 females from Wales and 43 males and 44 females from Slovenia were included in the study. Subjects ranged from 18 to 30 years of age. Four subgroups were formed: Slovenian males (SM), Slovenian females (SF), Welsh males (WM), and Welsh females (WF). 3D data were acquired using a laser scanning system. An average face for each subgroup was obtained using a previously validated mathematical algorithm. Facial differences were quantified after average faces had been superimposed using a previously validated method.

RESULTS

A total of 187 subjects from Slovenia and Wales formed 4 gender-specific subgroups. Absolute differences between subgroups ranged from 0.36 mm to 1.51 mm. The mean linear facial difference between SF and WF was 0.64 +/- 0.51 mm, and between SM and WM was 0.36 +/- 0.41 mm. Similarities between subgroups ranged from 13.43% (SF, WF) to 70.23% (SM, WM). Slovenian males and females tend to express Class III facial morphology when compared with the Welsh gender-specific subgroups. Male faces, in general, have more pronounced nasal, brow, and frontal regions and mandibles when compared with females. Female faces have more prominent malar and periocular areas.

CONCLUSION

The hypothesis is rejected. Morphologic differences exist between Slovenian and Welsh faces.

Incorrect orofacial functions until 5 years of age and their association with posterior crossbite

INTRODUCTION

In addition to heredity, sucking habits, impaired nasal breathing, and atypical swallowing patterns are considered important factors in the etiology of posterior crossbite. The purpose of this study was to assess irregular orofacial functions to determine their correlation with posterior crossbite.

METHODS

Two hundred forty-three children were examined at the ages 3, 4, and 5. Irregular orofacial functions and morphologic traits of malocclusion were clinically evaluated. The prevalence of posterior crossbite and the relationship with incorrect orofacial functions was determined. Data were analyzed by using the chi-square test and repeated measures analysis of variance (ANOVA).

RESULTS

Posterior crossbite at 5 years of age was found in 20% of the children. Half of the crossbite children had dummy sucking or were bottle-fed. Bottle feeding decreased during the observation years, but atypical swallowing, thumb sucking, and mouth breathing persisted. Mouth breathing and dummy sucking behavior were found to be statistically significantly different between the crossbite and noncrossbite groups of children. Atypical swallowing patterns increased in children with crossbite and decreased in those without crossbite. The difference was statistically significantly different (repeated measures ANOVA, P = 0.038).

CONCLUSIONS

Every clinical examination of children in the deciduous dentition with sucking habits should include assessment of orofacial functions, especially the swallowing pattern, which was found to be an important factor in the etiology for posterior crossbite development.

Early crossbite correction: a three-dimensional evaluation

A crossbite (CB) occurs in approximately 4-23 per cent of young children and may lead to mandibular and facial asymmetry. Therefore, early intervention is often necessary to create conditions for normal occlusal and facial development. The aim of this study was to assess facial asymmetry and palatal volume (pre- and post-treatment) in two groups of children, one with a unilateral CB and the other with no crossbite (NCB). Thirty children with CB (13 males, 17 females, mean age 4.9 +/- 0.98 years) and 28 children with NCB (17 males, 11 females, mean age 5.3 +/- 0.36 years) were included in the study. Those with a CB were treated with an intra-oral expansion appliance. The faces and dental casts of the children were scanned using a three-dimensional (3D) laser scanning device at baseline (T0) and after six months (T1) of treatment. Student's t-tests were used to assess differences between the two groups in facial symmetry and palatal volume over the 6 month period. The CB children had statistically significantly greater asymmetry of the face (P = 0.042), especially the lower third (P = 0.039), and a significantly smaller palatal volume (P = 0.045) than the NCB subjects at baseline. There were no statistically significant differences between the two groups at T1. Treatment of a CB in the primary dentition corrected the facial asymmetry, particularly the lower part of the face. The palatal volume of the CB children increased as a result of orthodontic intervention to similar levels exhibited by the NCB children.

Overjet as a predictor of sagittal skeletal relationships

Skeletal relationships in the sagittal plane do not always correspond with dental relationships. The aim of this study was to determine in which type of malocclusion the correlation between overjet and skeletal sagittal parameters assessed by lateral cephalogram analysis is the highest. The extent to which overjet can predict skeletal relationships in the sagittal plane was also assessed. Eighty-three subjects fulfilled the inclusion criteria (40 males and 43 females, mean age 16.3 +/- 4.3 years). Overjet was measured on study casts and sagittal skeletal relationships were analysed on lateral cephalograms. ANB angle, Wits appraisal, and convexity at point A were determined. Mean values and standard deviations of measured parameters were calculated for Class I, Class II division 1, and Class III malocclusion subjects. Correlation between overjet measured on study casts and sagittal skeletal parameters measured on lateral cephalogram was calculated. Overjet as a predictor of skeletal relationships was assessed by means of linear regression analysis. A statistically significant positive correlation (P < 0.01) was found between the values of overjet and ANB (r = 0.690), overjet and Wits appraisal (r = 0.750), and overjet and convexity at point A (r = 0.608) when assessing the whole sample. When linear regression between overjet and cephalometric parameters was assessed separately in Class I, Class II division 1, and Class III malocclusion subjects, the percentage of variability was statistically significant in just four pairs. The findings show that overjet is a good predictor of sagittal relationship only in subjects with a Class II division 1 malocclusion.

Assessment of malocclusion in the permanent dentition: reliability of intraoral measurements

Malocclusion assessment methods are based on registrations and measurements made on study casts, which requires that impressions be taken. In addition to being costly and time consuming, this process can be unpleasant for children and adolescents. Therefore, the aim of this study was to evaluate the reliability of intraoral measurements that compute a malocclusion index score to determine malocclusion severity in permanent dentition. The research was a part of a longitudinal study of 530 3-year-old children. In Slovenia at 14 years of age [mean = 14.8 years, standard deviation (SD) = 0.2], a cohort of 92 children (39 boys and 53 girls) were selected at random in a cross-sectional study. Quantitative registrations of space and occlusal anomalies were performed intraorally as well as on study casts. Kappa (kappa) statistics were used to evaluate agreement between clinical and study cast malocclusion assessment. Systematic bias of measurements was tested using Wilcoxon's signed-rank test. The results showed almost complete agreement between the two measurements for anterior crossbite, anterior open bite (AOB), transverse occlusion of the posterior teeth, and crowding (kappa = 0.81-1); excellent reliability for rotation of incisors and canines, for buccal segment relationship, overjet, and axial inclination of teeth (kappa = 0.61-0.80); and for the remainder of the traits the reliability was moderate: vestibular canine eruption, overbite, and midline deviation (kappa = 0.41-0.60). Intraorally small, but statistically significant (P < 0.05) lower scoring of axial inclination of teeth was identified. Overall classification into severity grades, based on total malocclusion score, showed excellent agreement between the two methods ( kappa = 0.84), without statistically significant bias. Malocclusion assessment, recorded and measured intraorally, is as reliable as assessment on study casts. The proposed method can be used in screening, in epidemiological studies, and in clinical orthodontic assessment.

Intra- and inter-examiner reliability of intraoral malocclusion assessment

Malocclusion assessment methods are based on measurements of study casts, which requires that impressions be taken. In addition to being costly and time consuming, this process can be unpleasant for children. Therefore, the aim of this study was to evaluate intra- and inter-examiner reliability of intraoral score measurements to determine malocclusion severity in the permanent dentition. The research was a part of a longitudinal study from which a cohort of 92 children (39 boys, 53 girls), with a mean age of 14.8 years (standard deviation = 0.18), were randomly selected and classified into severity grades based on total malocclusion score. Subsequently, 12 children were randomly selected for a reliability study to assess intra-examiner reliability of malocclusion trait measurements. Nine subjects gave informed consent to participate in the study. Quantitative registrations of space and occlusal anomalies were performed intraorally by five examiners, on two occasions with a 1-month interval between the two measurements. Intra- and inter-examiner reliability was determined using intraclass correlation coefficients (ICCs). Overall classification into severity grades, based on total malocclusion score, showed almost perfect intra-examiner reliability for all examiners (ICC = 0.97-0.99); inter-examiner ICC was almost perfect (0.97). Near perfect intra-examiner reliability was determined for eight occlusal trait measurements (ICC = 0.89-1.0); substantial reliability for midline deviation (ICC = 0.68), overbite (ICC = 0.78), but large variability for space condition assessment (ICC = 0.42-0.52). Inter-examiner reliability was almost perfect for the eight traits (ICC = 0.81-1.0); substantial reliability for midline deviation (ICC = 0.65), and axial tooth inclination (ICC = 0.75), but large variability for space condition assessment (ICC = 0.13-0.26). Intra- and inter-examiner malocclusion assessment, recorded and measured intraorally to determine malocclusion severity scores in 14-year old children, is reliable. It is therefore proposed as the method of choice to be used not only in epidemiological studies and screening but also in clinical orthodontic assessment.

The measurement of open apices of teeth to test chronological age of over 14-year olds in living subjects

Age determination in living subjects is a problem of increasing interest in our community, due to the increasing numbers of individuals without identification papers, who have immigrated illegally or committed crimes, and for whom it is necessary to verify whether they have reached the age of 14 years in order to be charged legally. Although the most widespread methods for age estimation refer to skeletal or dental analysis, these methods do present some drawbacks for identification of the age of 14. The aim of the present study is to discriminate between children who are or are not 14 years of age or older by measuring the open apices of teeth. We evaluated the OPGs of 447 persons aged between 12 and 16 years, of Italian, Croatian and Slovenian nationality. For each individual, dental maturity was estimated using the number of the seven left permanent mandibular teeth with root development complete, and normalized measurement of the open apices of the third molar. The results revealed that an individual is considered to be 14 years of age or older if all seven left permanent mandibular teeth have closed apices and the normalized measurement of open apices of the third molar is lower than 1.1.

Evaluation of 3 occlusal indexes: Eismann index, Eismann-Farčnik index, and index of orthodontic treatment need

INTRODUCTION

The aim of this study was to compare the validity, reliability, and time needed to use the Eismann index, the Eismann-Farcnik (EF) index, and the index of orthodontic treatment need (IOTN).

METHODS

One hundred pretreatment study casts of adolescent patients in the permanent dentition period (mean age, 15.4 years; SD, 0.4 year; 53 girls, 47 boys) were used. Three examiners trained and calibrated in the use of the Eismann and EF indexes and the IOTN scored the casts using the 3 indexes. A panel of 10 orthodontists individually rated the same casts for degree of malocclusion severity. The mean rating of the panel on the severity of malocclusion was used as the gold standard for evaluating the validity of the 3 indexes. Furthermore, the agreement of the 3 indexes in assessing the severity of malocclusion was evaluated. Ten randomly selected casts were reevaluated for the reliability study. Each evaluation was timed and rounded off to the nearest half minute.

RESULTS

The intraclass correlation coefficient indicated excellent agreement of the EF index with the ratings of the orthodontists (0.819), good agreement for the Eismann index (0.742), and moderate agreement for the IOTN (0.597). Receiver operating characteristic curves were plotted for the 3 indexes. The diagnostic accuracy, as determined by the area under the curve, was found to be the best for the EF index, followed by the Eismann index and the IOTN. Intraexaminer and interexaminer reliability was high (>0.75) for all 3 indexes. The most time-consuming methods were the EF (27.10 minutes) and the Eismann (26.86 minutes) indexes; the IOTN (1.97 minutes) was the least time-consuming method.

CONCLUSIONS

All 3 indexes are valid and reliable methods for assessing malocclusion severity. The EF index is the most time-consuming method, but it had the best agreement with clinical orthodontic diagnosis.

Comparison of intra-oral and study cast measurements in the assessment of malocclusion

Malocclusion assessment methods are based on registrations and measurements made on study casts, which requires that impressions be taken. In addition to being costly and time-consuming, this process can be unpleasant for very young children. Therefore, the aim of this study was to evaluate the reliability of intra-oral measurements that compute a malocclusion index score to determine malocclusion severity in the mixed dentition. The research was part of a longitudinal study in Slovenia on a sample of 530 3-year-old children. At 8 years of age (mean 8.5 years, standard deviation 0.2), a cohort of 101 children (44 boys, 57 girls) was randomly selected in a cross-sectional study. Quantitative registrations of space and occlusal anomalies were performed intra-orally as well as on study casts. Kappa (kappa) statistics were used to evaluate the agreement between clinical and study cast malocclusion assessments. Systematic bias of measurements was tested using Wilcoxon's signed rank test. The results showed complete agreement between the two measurements for anterior crossbite, anterior open bite and overjet scores (kappa = 1); excellent reliability for the buccal segment relationship (kappa = 0.93), transverse occlusion of posterior teeth (kappa = 0.87); and substantial agreement for overbite (kappa = 0.79) and midline deviation (kappa = 0.71). For the remainder of the traits the agreement was moderate: rotation of incisors (kappa = 0.58), crowding of upper incisors (kappa = 0.51), axial inclination of teeth (kappa = 0.44) and lower incisor crowding (kappa = 0.41). Intra-orally small, but statistically significant scoring of lower incisor rotation and crowding was identified. On the study casts the most favourable axial inclination was found for buccal segment occlusion. Overall classification into severity grades, based on the total malocclusion score, showed excellent agreement between the two methods (kappa = 0.89), without statistically significant bias. Malocclusion assessment, recorded and measured intra-orally, is as reliable as assessment on study casts. The proposed method can be used in screening, in epidemiological studies and in clinical orthodontic assessment.