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.

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.

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.

3D soft-tissue evaluation of a Class III treatment with rapid maxillary expander and face mask in pre-pubertal phase-A retrospective cohort study.

OBJECTIVES: The aim of this prospective controlled study was to evaluate the effectiveness of the rapid maxillary expander (RME) and face mask treatment using three-dimensional soft-tissue facial characteristics of pre-pubertal Class III children. SETTING AND SAMPLE POPULATION: CLIII and non-CLIII groups, both of 32 white children aged 6-8 years participated. MATERIAL AND METHODS: Facial surface images were obtained using stereophotogrammetry at T0 and T1 and were superimposed. Landmark-based and surface-based facial parameters were measured, and group differences were quantified (ANOVA; P ≥ .05). RESULTS: CLIII children had less mid-face prominence, shorter lower facial height and protruded mandible when compared to non-CLIII children at T0. At T1, the differences between the groups were not statistically significant, indicating successful correction. After the RME/face mask treatment, the n-sn and sn-pg distances increased by 1.5 mm and 2.2 mm, respectively. The distance from sn to the n-pg line increased by 1 mm, the n-sn-pg angle decreased by almost 2°. Pogonion moved downward by 2.5 mm and posteriorly by 3 mm. The surface-based measurements between the groups after treatment showed anterior movement in the mid-face region and the upper lip region. The lower lip and chin region moved posteriorly in the CLIII group and anteriorly in the non-CLIII group. CONCLUSIONS: After RME/face mask treatment, the lower facial height increased, the maxilla moved anteriorly, and the mandible moved posteriorly. Consequently, CLIII children reached the respective values of the non-CLIII children, indicating a harmonious facial appearance of CLIII children. The results have been obtained using non-invasive technique.

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.

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.

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.

Three-dimensional ultrasound evaluation of tongue posture and its impact on articulation disorders in preschool children with anterior open bite.

Background Tongue posture plays an important role in the etiology of anterior open bite (AOB) and articulation disorders, and is crucial for AOB treatment planning and posttreatment stability. Clinical assessment of tongue posture in children is unreliable due to anatomical limitations. The aim of the study was to present functional diagnostics using three-dimensional ultrasound (3DUS) assessment of resting tongue posture in comparison to clinical assessment, and the associations between the improper tongue posture, otorhinolaryngological characteristics, and articulation disorders in preschool children with AOB. Patients and methods A cross-sectional study included 446 children, aged 3-7 years, 236 boys and 210 girls, examined by an orthodontist to detect the prevalence of AOB. The AOB was present in 32 children. The control group consisted of 43 children randomly selected from the participants with normocclusion. An orthodontist, an ear, nose and throat (ENT) specialist and a speech therapist assessed orofacial and ENT conditions, oral habits, and articulation disorders in the AOB group and control group. Tongue posture was also assessed by an experienced radiologist, using 3DUS. The 3DUS assessment of tongue posture was compared to the clinical assessment of orthodontist and ENT specialist. Results The prevalence of AOB was 7.2%. The AOB group and the control group significantly differed regarding improper tongue posture (p < 0.001), and articulation disorders (p < 0.001). In children without articulation disorders from both groups, the improper tongue posture occured less frequently than in children with articulation disorders (p < 0.001). After age adjustment, a statistical regression model showed that the children with the improper tongue posture had higher odds ratios for the presence of AOB (OR 14.63; p < 0.001) than the others. When articulation disorders were included in the model, these odds ratios for the AOB became insignificant (p = 0.177). There was a strong association between the improper tongue posture and articulation disorders (p = 0.002). The 3DUS detected the highest number of children with improper resting tongue posture, though there was no significant difference between the 3DUS and clinical assessments done by orthodontist and ENT specialist. Conclusions The 3DUS has proved to be an objective, non-invasive, radiation free method for the assessment of tongue posture and could become an important tool in functional diagnostics and early rehabilitation in preschool children with speech irregularities and irregular tongue posture and malocclusion in order to enable optimal conditions for articulation development.

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.

Three-dimensional evaluation of the maxillary arch and palate in unilateral cleft lip and palate subjects using digital dental casts.

OBJECTIVES: To assess arch width, palatal surface area, and volume in surgically treated unilateral cleft lip and palate (UCLP) in mixed dentition children in comparison with non-cleft lip and palate (NCLP) children using a 3D laser scanning. MATERIALS AND METHODS: 38 subjects (Caucasian origin), 5.63-11.9 years of age (mean, 9.33 ± 1.67 years), were included. 19 in each group (UCLP and NCLP). Digital dental casts were obtained using a 3 Shape R700 laser scanner. Intercanine and intermolar widths (cusp and gingival levels), palatal surface area and volume were measured. An independent sample Student's t-test and an ANOVA were undertaken with significance level set as P < 0.05. RESULTS: Intercanine widths at the cusp (5.60 mm; P < 0.001) and at the gingival level (3.11 mm; P = 0.014), palatal area (141.5 mm2; P = 0.009) and volume (890.7 mm3; P = 0.029) were significantly lower in the UCLP compared to the control group. LIMITATIONS: A smaller part of the subjects was in late mixed dentition phase. To overcome this limitation a matched control group was used. In seven subjects with UCLP, some teeth were missing, which might have had an influence on the dental measurements. However, these subjects could not be excluded because eliminating more severely affected subjects, would have introduced bias. CONCLUSIONS: Three-dimensional evaluation of the maxillary arch and palate highlighted significant differences between UCLP and non-UCLP subjects in mixed dentition phase, suggesting that orthopaedic maxillary expansion is advisable in UCLP.

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.

Three-dimensional Analysis of Normal Facial Morphologies of Asians and Whites: A Novel Method of Quantitative Analysis.

The purpose of this study is to compare 3-dimensional facial averages of Asians (Koreans and Chinese) and Houstonian white faces using a (3-dimensional) surface imaging system. METHODS: Three-dimensional images of Korean adults (Seoul, Korea) with class I malocclusion captured using the 3dMDface. The images of 138 Koreans were processed to generate average male and female facial shells using Rapidform 2006 plus pack 2 software and then superimposed and compared with the average shells of Chinese adults (Xi' An, China) and white adults (Houston, Tex.). RESULTS: The average Korean male and female faces were wider with prominent malar and zygomatic areas when compared with the white faces. The average white male and female faces showed more protrusion in the glabella, nasion, rhinion, and the soft-tissue pogonion than the Korean faces. The average Korean male face was retrusive at masseteric region while having more prominent lips, nasal tip, and supraglabella than the Chinese counterpart. The average Korean female face was narrower than the average Chinese female face, but there was more protrusion in the periorbital, nasal tip, and malar region seen in the Korean female face. CONCLUSIONS: Although the average faces of Chinese and Korean populations in this study showed remarkable similarities, there were distinct differences seen in the facial morphology of the 2 Asian groups. Three-dimensional imaging can be effectively used to establish population facial norms and to quantify the variations seen between different ethnicities. This information may be used in the clinical environment for plastic, oral, and maxillofacial surgery and orthodontics.

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]. / Repousser les limites de la dimension transversale. Asymétrie faciale, volume du palais et posture linguale chez les enfants ayant une occlusion croisée unilatérale postérieure : évaluation tridimensionnelle d'un traitement précoce.

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.

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.

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.

Three-dimensional assessment of facial asymmetry among pre-pubertal class III subjects: a controlled study.

BACKGROUND/OBJECTIVE: Facial asymmetry is very common in adult class III patients; however, the degree of facial asymmetry in growing class III subjects has been poorly investigated. Therefore, the aim was to assess the degree of facial asymmetry of growing class III subjects and to compare it with a sample of growing subjects without malocclusion, recorded using a three-dimensional laser scanning method and classified according to the dentition phase. SUBJECTS/METHODS: A group of 156 Caucasian subjects, 52 with class III malocclusion (28 females and 24 males) and 104 without malocclusion (control, 51 females and 53 males), with an overall mean age 6.7±1.4 years (range 4.3-10.3 years), were included. The subjects were further subdivided according to the presence of either primary or early/intermediate mixed dentitions. Facial asymmetry was assessed on three-dimensional surface facial images obtained using a laser scanning device in terms of mirrored face distances and percentages of asymmetry. Multivariate analyses were used to assess the differences among class III and control groups. RESULTS: Complete facial symmetry was not seen in any subject. No significant differences of facial asymmetry were observed between the class III and control groups, neither in the primary nor in the early/intermediate mixed dentition phases. LIMITATIONS: No conclusions about longitudinal changes in the degree of facial asymmetry among class III subjects could be drawn from the present cross-sectional study. CONCLUSIONS: Based on three-dimensional facial asymmetry analysis, class III subjects do not show clinically relevant facial asymmetry, at least during the pre-pubertal growth period.

Three-dimensional assessment of palatal change in a controlled study of unilateral posterior crossbite correction in the primary dentition.

The aim of this study was to quantify the palatal change in three groups of children: children with a unilateral posterior crossbite (TCB) who were treated, children with untreated unilateral posterior crossbite (UCB), and children without a crossbite (NCB). Study casts of 60 Caucasian children in the primary dentition (20 TCB, 20 UCB, and 20 NCB), aged 5.4 ± 0.7 years, were collected at baseline (T1) and at 1-year follow-up (T2). Both TCB and UCB groups had unilateral posterior crossbite and midline deviation. The TCB group was treated using a cemented acrylic splint expander in the upper arch. The study casts were scanned using a laser scanner and palatal surface area, palatal volume, and symmetry of the palatal vault were evaluated and compared between the three groups. At T1, the palatal volume of TCB (2698 mm(3)) and UCB (2585 mm(3)) was significantly smaller than that of NCB (3006 mm(3); P < 0.05, analysis of variance test). After treatment, the palatal volume of the TCB group (3087 mm(3)) increased and did not differ from the NCB group (3208 mm(3)), whereas the UCB (2644 mm(3)) had a significantly smaller palatal volume than the NCB or TCB groups (P < 0.05). The increase of palatal volume in the TCB group (389 mm(3)) was significantly greater than in the UCB (59 mm(3)) and NCB (202 mm(3)) groups. The symmetry of the palatal vault was greater than 90 per cent in all three groups at T1 and at T2. Treatment of unilateral posterior crossbite in the primary dentition has a significant effect, particularly on the palatal volume increase.