Reliability and safety of miniscrew insertion planning with the use of lateral cephalograms assessed on corresponding cone-beam computer tomography images.

BACKGROUND/OBJECTIVES: Recently, lateral cephalograms have been proposed for guided miniscrew insertion planning. Therefore, the aim was to assess the reliability and safety of such planning on corresponding cone-beam computer tomography (CBCT) images. MATERIALS/METHODS: Intraoral scans, lateral cephalograms, and CBCT images of 52 subjects (even sexes distribution), aged 15.1 ±â€…2.5 years, were included. Miniscrew (n = 104) insertion planning was performed using lateral cephalograms superimposed on the maxillary intraoral scans, while the assessment of their bicortical placement, length in bone, contact with adjacent teeth, incisive canal, and nasal floor perforation was done on corresponding superimposed CBCT images. Moreover, maxillary incisor inclination, crowding, and the maxillary intercanine width were measured. RESULTS: The overall miniscrew length in bone was 7.2 ±â€…1.3mm. Bicortical placement was seen in 58.7% of the sample (38.5% of subjects). Incisive canal and nasal floor perforation was seen in 25% and 21.2% of subjects, respectively. No contact of the miniscrew with adjacent teeth was recorded. A negative significant interaction was seen between the miniscrew length in bone, the percentage of total miniscrew length and maxillary anterior teeth crowding (ß, -0.10, P = .047 and ß, -0.90, P = .006, respectively). Moreover, a positive significant interaction was seen between the incisive canal perforation and maxillary anterior teeth crowding (OR = 1.32, P = .021). LIMITATIONS: Exclusion of subjects with impacted teeth. CONCLUSIONS: Miniscrew insertion planning using lateral cephalograms, despite being safe in preventing contact with adjacent teeth, is limited in achieving bicortical placement and insufficient in completely avoiding incisive canal and nasal floor perforation.

Changes in the swallowing pattern and tongue posture during the transition from deciduous to mixed dentition-a longitudinal ultrasonography study.

BACKGROUND: Given the importance that swallowing pattern and tongue posture might have in the aetiology of malocclusion, it appears important to be aware of the physiological changes of tongue function and its posture. OBJECTIVES: The study aimed to assess changes of the swallowing pattern and tongue posture during the transition from the deciduous to mixed dentition and the association between them. MATERIALS AND METHODS: The study included 57 subjects aged 5.87 ±â€…0.5 with normal occlusion, orofacial functions, no history of trauma, or orthodontic treatment. Ultrasonography was used for the assessment of tongue posture and swallowing pattern, where the spontaneous act of swallowing was recorded. To evaluate the possible effect of incisors' eruption, the swallowing pattern and tongue posture ultrasonograms were compared at the deciduous (DD), early mixed (EMD), and intermediate mixed (IMD) timepoints. RESULTS: A significant association between the swallowing pattern and tongue posture at the DD and IMD timepoint was found. Moreover, the visceral swallowing pattern decreases with age (odds ratio [OR] = 0.777), as well as with a prolonged phase IIa (OR = 0.071), while it increases when the tongue is postured on the mouth floor (OR = 5.020). LIMITATIONS: The young age of the investigated subjects, direct contact of the probe, and the determination of the rest phase of the tongue were considered limitations. CONCLUSIONS: No statistically significant changes in swallowing pattern and tongue posture occurred during the transition period; however, a significant association between the swallowing pattern and tongue posture among subjects with normal occlusion, regardless of the dentition phase was detected.

Skeletal and dental effects of serial extractions performed with or without maxillary expansion-A retrospective controlled study.

OBJECTIVES: The study aimed to compare severe crowding treatment's skeletal and dental effects by serial extractions or maxillary expansion and serial extractions in the mixed dentition phase. SETTING AND SAMPLE POPULATION: The retrospective controlled study included lateral cephalograms of 78 subjects aged 8.5 ± 1.4 years, 52 consecutively treated because of severe crowding, and 26 untreated controls matched for baseline age and observational period. METHODS: Subjects were clustered according to the treatment modality, either serial extraction (EX) or expansion and extraction (EXP-EX) group. Sagittal and vertical skeletal as well as dental cephalometric parameters were assessed at baseline and after the eruption of all permanent posterior teeth, and group comparisons were performed. RESULTS: Both treatment modalities significantly affected the vertical skeletal parameters in terms of decreasing the mandibular and occlusal plane inclination and increasing the facial height index. A distinct treatment effect on the gonial angle was observed, with a significant decrease in its superior part observed in both extraction groups. The annualized changes in the superior part of the gonial angle significantly differ (P = .036) between the Control (-0.04 ± 0.6), EX (-0.44 ± 0.6) and EXP-EX (-0.34 ± 0.5) groups. Upper and lower incisor inclination did not change significantly in any of the groups; however, the interincisal angle at follow-up was significantly smaller in the Control compared with both treated groups. CONCLUSIONS: Serial extractions and a combination of maxillary expansion and serial extractions have similar significant skeletal effects, mainly affecting vertical cephalometric parameters if performed during the pre-pubertal growth phase.

Circumpubertal maxillomandibular growth in untreated subjects with skeletal Class II relationship: A controlled longitudinal study according to the third finger middle phalanx maturation.

INTRODUCTION: Despite the substantial prevalence of skeletal Class II Division 1 malocclusion, only a few studies analyzed the maxillomandibular growth changes in these subjects with contrasting results. This study compared the longitudinal maxillomandibular growth changes in growing subjects with Class I and II skeletal relationships, specifically during the circumpubertal growth phase assessed by the modified third finger middle phalanx maturation (MPM) method. An attempt to uncover any maxillomandibular growth peak in subjects with Class II relationship has been followed. METHODS: From the files of the Burlington Growth Study, a total of 32 subjects (13 males, 19 females) with at least 7 annual lateral cephalograms taken at 9 and 16 years old were included and equally distributed between Class II and Class I groups matched for sex. Overall changes in 12 cephalometric parameters were calculated, and maxillomandibular growth peak was also identified individually and used to register subjects according to the year of growth peak ± 2 years. According to this procedure, annualized changes (trends) were analyzed along with the corresponding prepubertal, pubertal, and postpubertal MPM stages. RESULTS: No significant differences were seen between subjects with Class I and II skeletal relationships at 9 and 16 years, except for the parameters of the sagittal maxillomandibular relationship, such as ANB angle. Overall, changes for all the cephalometric parameters were similar between the groups, except for the CoGn distance increment that was significantly lower in the subjects with a Class II relationship. In both groups, the annual changes in CoA, CoGn, and CoGo distances showed a clear peak at the time point corresponding to a median MPM stage 3. CONCLUSIONS: In subjects with a skeletal Class II relationship, mandibular deficiency appears to be mostly established during the prepubertal growth stage and further aggravated during puberty. However, the maxillomandibular growth trend in subjects with Class II relationship is generally similar to that of subjects with a Class I relationship, including the existence of a pubertal peak.

Diagnostic ability of the primary second molar crown-to-root length ratio and the corresponding underlying premolar position in estimating future expander anchoring teeth exfoliation.

OBJECTIVES: The aim was to assess the diagnostic ability of the crown-to-root length ratio of the primary second molar and the position of the corresponding underlying premolar in estimating future anchoring teeth exfoliation during maxillary expansion. SETTING AND SAMPLE POPULATION: Fifty-four subjects (30 females, 24 males; 108 teeth) aged 8.2 ± 1.0 years that underwent palatal expansion. METHODS: The upper second premolar position of the corresponding expander anchoring primary molar was determined in relation to the ipsilateral first permanent molar half-pulp chamber (HPC) line on panoramic radiographs. Subjective and objective (based on measurements) assessments of the crown-to-root length ratio of anchoring primary molars were performed. Exfoliation after the expansion was recorded over a retention period of 12 months. All the assessments were performed individually by three examiners at two 3-week-apart sessions, trained and calibrated before enrolment. The intra-/inter-examiner agreements were evaluated, and the diagnostic accuracy of the methods was calculated. RESULTS: All methods exhibited almost perfect intra- and at least substantial inter-examiner agreement (Kappa >0.8 and ≥0.63, respectively). Good diagnostic accuracy was seen for the premolar position to the HPC line (0.7-0.8), while the crown-to-root length ratio methods exhibited hardly sufficient accuracy. The diagnostic agreement of the methods was fair. CONCLUSIONS: When primary molars are considered as anchoring teeth for maxillary expansion, the premolar position in relation to the HPC line appears to be the most valid and reliable method for predicting their stability. Despite high repeatability values, the crown-to-root length ratio needs a cut-off point re-definition to increase its predicting ability.

Factors related to maxillary expander loss due to anchoring deciduous molars exfoliation during treatment in the mixed dentition phase.

OBJECTIVES: The aim was to identify factors associated with maxillary expander loss due to anchoring deciduous molars exfoliation and assess the diagnostic accuracy of the upper second premolar cusp position as a prognostic factor for the exfoliation of its corresponding deciduous molar. MATERIALS/METHODS: Ninety-two subjects aged 8.4 ± 1.1 years, treated with a Haas or hyrax expander, and using the same expansion protocol and deciduous teeth as anchorage were included. The position of the upper second premolar cusp, according to the half pulp chamber (HPC) line of the ipsilateral upper first permanent molar, was assessed on pre-treatment panoramic radiographs. RESULTS: A significant association between anchoring deciduous molar exfoliation and the position of the upper second premolar cusp according to the HPC line (P = 0.002; odds ratio = 5.7) was seen, while there was no association with gender, age, treatment duration, and type of expander. The median survival time for an anchoring deciduous molar, when the underlying premolar cusp was touching/crossing the HPC line, was 13.0 (11.7; 14.2) months. The upper second premolar cusp position to the HPC line showed high accuracy (at least 76.11 per cent) and substantial repeatability (at least 0.7) as a prognostic factor for the corresponding second deciduous molar exfoliation. LIMITATIONS: Applicability in the mixed dentition phase with fully erupted upper first permanent molars. CONCLUSIONS: The probability of a second deciduous molar to be successfully used as maxillary expander anchorage for at least 16 months is above 94 per cent; when at baseline, the corresponding premolar cusp is apical to the HPC line.

Are Metal Ions That Make up Orthodontic Alloys Cytotoxic, and Do They Induce Oxidative Stress in a Yeast Cell Model?

Compositions of stainless steel, nickel-titanium, cobalt-chromium and ß-titanium orthodontic alloys were simulated with mixtures of Fe, Ni, Cr, Co, Ti and Mo metal ions as potential oxidative stress-triggering agents. Wild-type yeast Saccharomyces cerevisiae and two mutants ΔSod1 and ΔCtt1 were used as model organisms to assess the cytotoxicity and oxidative stress occurrence. Metal mixtures at concentrations of 1, 10, 100 and 1000 µM were prepared out of metal chlorides and used to treat yeast cells for 24 h. Every simulated orthodontic alloy at 1000 µM was cytotoxic, and, in the case of cobalt-chromium alloy, even 100 µM was cytotoxic. Reactive oxygen species and oxidative damage were detected for stainless steel and both cobalt-chromium alloys at 1000 µM in wild-type yeast and 100 µM in the ΔSod1 and ΔCtt1 mutants. Simulated nickel-titanium and ß-titanium alloy did not induce oxidative stress in any of the tested strains.

Cervical vertebral maturation: Are postpubertal stages attained in all subjects?

INTRODUCTION: The cervical vertebral maturation (CVM) method comprises 6 stages reported to be prepubertal (1 and 2), pubertal (3 and 4) and postpubertal (5 and 6), and its use has been recommended for planning treatment timing in orthodontics. Reliable use of the method implies that pubertal stages have to mature into postpubertal as soon as the growth peak is terminated. The present study was aimed at determining whether postpubertal CVM stages 5 or 6 are attained in all subjects. METHODS: A total of 450 adult subjects (270 females and 180 males; mean age, 30.4 ± 27.3 years; range, 20-45 years) seeking orthodontic treatment and having a lateral head film were included in the study. Customized cephalometric analysis was used, and each recording was converted into an individual CVM code according to the concavities of the C2 to C4 and shapes of C3 and C4. The retrieved CVM codes, either falling within the reported norms (regular cases) or not (exception cases), were also converted into the CVM stages and a newly introduced CVM score (0-9) capable of defining intermediate stage. RESULTS: The most frequent CVM stage was 5, while the CVM stage 6 was attained in only one third of the sample. Up to about 11% of adult subjects showed the pubertal CVM stage 4. Irrespective of the CVM stage or CVM score, no significant differences were seen between the sexes or across ages. The C4 showed a rectangular vertical shape in only 16.4% of the cases. CONCLUSIONS: The percentage of adult population maintaining a pubertal CVM stage 4 is not high, but still relevant from a clinical standpoint. In light of this finding, planning treatment timing-based only on CVM appears not fully reliable.

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.

Cervical vertebral maturation method and mandibular growth peak: a longitudinal study of diagnostic reliability.

Background/objectives: The capability of the cervical vertebral maturation (CVM) method in the identification of the mandibular growth peak on an individual basis remains undetermined. The diagnostic reliability of the six-stage CVM method in the identification of the mandibular growth peak was thus investigated. Subjects/Methods: From the files of the Oregon and Burlington Growth Studies (data obtained between early 1950s and middle 1970s), 50 subjects (26 females, 24 males) with at least seven annual lateral cephalograms taken from 9 to 16 years were identified. Cervical vertebral maturation was assessed according to the CVM code staging system, and mandibular growth was defined as annual increments in Co-Gn distance. A diagnostic reliability analysis was carried out to establish the capability of the circumpubertal CVM stages 2, 3, and 4 in the identification of the imminent mandibular growth peak. Results: Variable durations of each of the CVM stages 2, 3, and 4 were seen. The overall diagnostic accuracy values for the CVM stages 2, 3, and 4 were 0.70, 0.76, and 0.77, respectively. These low values appeared to be due to false positive cases. Limitations: Secular trends in conjunction with the use of a discrete staging system. In most of the Burlington Growth Study sample, the lateral head film at age 15 was missing. Conclusions/Implications: None of the CVM stages 2, 3, and 4 reached a satisfactorily diagnostic reliability in the identification of imminent mandibular growth peak.

Influence of long-term in vivo exposure, debris accumulation and archwire material on friction force among different types of brackets and archwires couples.

OBJECTIVE: The aim was to assess the influence of long-term in vivo exposure, debris accumulation and archwire material on static and kinetic friction force among different types of brackets and archwires couples. MATERIAL AND METHODS: Friction testing was performed among four lower incisors' brackets, conventional and self-ligating (SL), coupled with either nickel-titanium or stainless steel archwires, as-received and in vivo exposed in 18 subjects. The friction testing was performed for a sliding distance of 14 mm at a speed of 10 mm/min, with a starting force of 0.2 N. Wear and quantitative assessment of debris accumulation was performed on pictures of brackets obtained using a scanning electron microscope. Non parametric tests were used for statistical analysis. RESULTS: Only bracket type, but not exposure duration, amount of debris accumulation, archwire material or their manufacturer, was significantly correlated with both static (rho = 0.602, P < 0.001) and kinetic (rho = 0.584, P < 0.001) friction force. Within each bracket type no significant difference was observed between as-received and in vivo exposed brackets for any friction parameter except for the SL brackets in which significantly higher static and kinetic (P = 0.001, at least) friction forces were seen in in vivo exposed SL brackets (164.9 cN and 217.63 cN, respectively) in comparison with as-received SL brackets (19.69 cN and 55.72 cN, respectively). LIMITATION: The frictional testing was performed in the dry condition which might have influenced the results. CONCLUSION: A significant correlation was seen between friction force and bracket type, while treatment duration, amount of debris accumulation, archwire material or their manufacturer was not significantly correlated to it. Nevertheless, higher friction forces were measured among in vivo aged SL brackets in comparison with as-received ones.

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 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.

Gingival crevicular fluid alkaline phosphate activity during the retention phase of maxillary expansion in prepubertal subjects: A split-mouth longitudinal study.

INTRODUCTION: The aim of this study was to monitor the alveolar bone formation at the tension sites of teeth supporting the appliances for rapid maxillary expansion (RME) during the retention phase according to the local gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity. METHODS: This split-mouth prospective study included 23 prepubertal subjects (15 girls, 8 boys; mean age, 9.0 ± 1.4 years) who had a constricted maxillary arch and were undergoing RME. Periodontal parameters, including probing depth, were recorded at 3 and 6 months after RME. Furthermore, the GCF ALP activity was measured at the tension sites of the supporting test teeth (TT) and at the antagonist control teeth (CT) sites. RESULTS: Periodontal parameters were generally similar between the TT and CT sites during the study, with the exception that probing depth underwent a slight increase at the TT sites. At baseline, the GCF ALP activity was similar between the TT and CT sites; however, at both 3 and 6 months, significantly greater enzymatic activity was seen at the TT sites. The overall probing depth changes were not significantly correlated with the corresponding GCF ALP activity changes for either the TT or the CT sites. CONCLUSIONS: Alveolar bone formation at the tension sites would last up to 6 months of retention after RME. These results warrant more comprehensive studies to assess whether the GCF ALP activity has potential as a diagnostic tool for bone formation during the retention phase of RME.

Palatal surface and volume in mouth-breathing subjects evaluated with three-dimensional analysis of digital dental casts-a controlled study.

OBJECTIVE: To compare the anatomical characteristics of the maxillary arch, identified as palatal surface area and volume, between mouth-breathing and nose-breathing subjects using a three-dimensional (3D) analysis of digital dental casts. METHODS: Twenty-one Caucasian subjects (14 females and 7 males) with a mean age of 8.5 years [standard deviation (SD) 1.6 years] were selected according to the following criteria: mouth-breathing pattern due to allergic rhinitis, early mixed dentition, skeletal Class I relationship, and pre-pubertal stage of cervical vertebral maturation. This study group (SG) was compared with a control group (CG) of 17 nose-breathing subjects (9 females and 8 males, mean age: 8.5 years; SD: 1.7 years). For each subject, initial dental casts were taken and the upper arch was scanned using a 3D laser scanner. On each digital model, 3D measurements were performed to analyse maxillary arch morphology. Between-group differences were tested with the independent sample Student's t-test (P < 0.05). RESULTS: In mouth-breathing subjects, changes in physiological function of the upper respiratory tract resulted in skeletal adaptations of the maxillary arch. In the SG, both palatal surface area and volume were significantly smaller when compared with values of the CG. In particular, the palatal surface area and palatal volume were, respectively, 13.5 and 27.1 per cent smaller in the SG when compared to the CG. CONCLUSIONS: Subjects with prolonged mouth breathing showed a significant reduction of the palatal surface area and volume leading to a different development of the palatal morphology when compared with subjects with normal breathing pattern.

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 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.

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.