Orthod Craniofac Res [journal]
- Relationship between the cranial base and the mandible in artificially deformed skulls. [JOURNAL ARTICLE]
- Orthod Craniofac Res 2016 Aug 10.
There is controversy regarding the relationship between mandibular position and alterations of the cranial base that provoke a more anterior location of the glenoid fossa. Artificially deformed skulls display marked alterations of the cranial base. This study evaluates mandibular changes as function of the morphology of the cranial base in these skulls.A geometric morphometric study was performed on lateral cephalometric X-rays of three groups of skulls: 32 with anteroposterior deformity, 17 with circumferential deformity and 39 with no apparent deformity.In artificially deformed skulls, the cranial base was deformed causing the mandibular condyle to be in a more anterior position. There was a complete remodelling of the mandible involving narrowing and elongation of the mandibular ramus, rotation of the corpus of the mandible and increased vertical height of the symphysis. Forward displacement did not occur. Integration between mandible and cranial base is not altered by deformation of the skull.Deformity of the cranial vault exerts an influence on the mandible, supporting the theory of modular units in complete integration. This also supports the theory that mandibular prognathism is a multifactorial result and not a direct effect of displacement of the cranial base.
- Cell morphologic changes and PCNA expression within craniofacial sutures during monkey Class III treatment. [JOURNAL ARTICLE]
- Orthod Craniofac Res 2016 Jul 13.
To evaluate and compare the cellular morphologic changes and proliferating cell nuclear antigen (PCNA) expression within craniofacial sutures in growing Rhesus monkeys treated with a Class III functional appliance.Six Rhesus monkeys in the mixed dentition stage were divided into three groups: a 45-day experimental group, a 90-day experimental group, and a control group. Monkeys in the experimental groups were fitted with a Class III magnetic twin-block appliance. Cellular changes in six craniofacial sutures-the zygomaticomaxillary, zygomaticotemporal, transverse palatine, pterygopalatine, zygomaticofrontal, and frontomaxillary sutures were qualitatively and quantitatively evaluated by means of histomorphologic analysis, TEM, and immunohistochemical test of PCNA.Obvious and altered bone remodeling combined with bone deposition and resorption was present in craniofacial sutures in the experimental groups. Increased activity of enlarged fibroblasts with abundant organelles was revealed. PCNA expression increased in the 45-day group compared with the control group, followed by the 90-day group. The highest percentage of PCNA-positive cells was found in the pterygopalatine suture in the 45-day group and the zygomaticomaxillary suture in the 90-day group.The pterygopalatine and zygomaticomaxillary sutures are more active among the craniofacial sutures in the craniofacial complex remodeling during Class III treatment. The magnetic twin-block appliance effectively promoted suture remodeling by enhancing the activity and proliferation of osteoblasts, osteoclasts, and fibroblasts, especially in the early phase.
- Effect of a thin-neck pacifier on primary dentition: a randomized controlled trial. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):127-36.
To evaluate changes in occlusal characteristics in the primary dentition that occur after introducing a thin-neck pacifier (TNP) to children with previously diagnosed pacifier-associated anterior open bite (AOB) and increased overjet.Department of Preventive and Pediatric Dentistry, Jena University Hospital, Germany. Subjects were 86 children (mean age 20.3 months) with a pacifier-associated open bite or overjet ≥2 mm.Randomized controlled trial. Subjects were randomly assigned: group I (n = 28), intervention group using a TNP; group II (n = 30), control group, using a conventional or physiological pacifier; and group III (n = 28), intervention group, Gold standard, weaned off pacifier. Participants were re-examined after 3, 6, 9 and 12 months by an operator, blinded for the treatment.After 12 months data for 63 children (mean age 33.1 months) were analyzed (I: n = 24; II: n = 22; III: n = 17). There was a significant difference between the groups regarding mean overjet (group I: 2.7 ± 0.5 mm, group II: 3.2 ± 0.7 mm, group III: 2.4 ± 0.5 mm, Kruskal-Wallis, p = 0.002) and AOB (group I: -1.2 ± 0.3 mm, group II: -2.2 ± 0.3 mm, group III: -0.8 ± 0.8 mm, Kruskal-Wallis, p < 0.001). The differences between group I and II regarding increased overjet (3.1 ± 0.2 mm vs. 3.6 ± 0.3 mm, Mann-Whitney, p < 0.001) and extent of AOB (-1.2 ± 0.3 mm vs. -2.2 ± 0.3 mm, Mann-Whitney, p < 0.001) were statistically significant.Use of TNP resulted in better clinical measurements for in overjet and overbite compared with the continuing use of conventional or physiological pacifiers.
- Facial biometry of Amazon indigenous people of the Xingu River - Perspectives on genetic and environmental contributions to variation in human facial morphology. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):169-79.
To evaluate facial morphology of non-mixed indigenous people living in the Xingu region. Studies on these populations report that the total genetic diversity is as high as that observed for other continental populations. On the other hand, eating habits are different between indigenous and urban population, as indigenous people still have traditional habits.The sample consisted of 106 indigenous subjects, in permanent dentition stage, belonging to four groups: Arara-Laranjal (n = 35), Arara-Iriri (n = 20), Xikrin-Kaiapó (n = 24), and Assurini (n = 27).Standardized facial photographs were obtained, and fourteen measurements were analyzed. Intra- and intergroup homogeneities were examined by discriminant analysis, followed by anova and Kruskal-Wallis tests. Sexual dimorphism to each village was analyzed by Student's t-test or Mann-Whitney test, at p < 0.05.Significant facial differences were found between male and female, indicating that sex data should not be grouped for intergroup comparison. Discriminant analysis showed a large intergroup heterogeneity, while an intragroup homogeneity was found, especially for females. It was also observed that some morphological features of the face are specific to some villages, regardless of ethnicity.Facial morphological characteristics were strongly different among groups, even comparing villages from the same ethnicity. Furthermore, a low diversity within groups was observed. Our findings, supported by previous reports on genetics and eating habits in these populations, reinforce the role of the genetic determination on craniofacial morphology.
- Effect of hyaluronic acid on bone formation in the expanded interpremaxillary suture in rats. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):154-61.
To evaluate the histomorphometric effects of different molecular weight hyaluronic acid on bone formation in rats after expansion of the interpremaxillary suture.Twenty-four male Sprague Dawley rats were divided into three groups. Each group was subjected to expansion for 5 days and retention for 10 days. Group 1 received 50 μl of high molecular weight hyaluronic acid (HMWHA), group 2 received 50 μl of low molecular weight hyaluronic acid (LMWHA), and the control group received same amount of saline solution to the interpremaxillary suture. Ten days after injection, the rats were killed and their maxillas dissected. For the histomorphometric evaluation, blocks were serially sectioned at 10-μm intervals. Sections were stained with hematoxylin-eosin (HE) and evaluated with image analysis software. Bone area (μm²) (BA), bone perimeter of suture borders (μm) (BP), and ratio of osteoblast cells and capillary cells to BA and BP parameters were evaluated.HMWHA showed a statistically higher ratio of osteoblast and capillary cell scores compared with the LMWHA and control groups (p < 0.05). There were no statistically significant differences in between LMWHA and control groups (p > 0.05).Local injection of HMWHA in the interpremaxillary suture after rapid maxillary expansion stimulated new bone formation, which may shorten the retention period and may reduce the risk of relapse. LMWHA has no effect on bone formation in interpremaxillary suture.
- Biomechanical potential of the temporal muscle in brachyfacial and dolichofacial subjects: a study on dry mandibles. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):162-8.
To measure the lengths of the force and resistance arms, in order to calculate the mechanical advantage and muscular work of the human temporalis muscle (TM) in brachyfacial (BR) and dolichofacial (DO) subjects.Mandibles from 49 subjects of both genders (BR n = 9; DO n = 40) from the collection of the Laboratory of Human Anatomy at Universidade de Santa Cruz do Sul, Rio Grande do Sul, Brazil, were analyzed.The distance between the condylar process and the coronoid process (insertion site of the TM) represented the length of the force arm (LFA ) of the TM. The distance between the condylar process and the mental protuberance represented the length of the resistance arm (LRA ). Thus, the mechanical advantage of the TM was obtained using the following ratio: LFA /LRA , while the muscular work (LRA /LFA ) of the TM was obtained using the inverse of this ratio.When compared with the DO, the parameters of the BR are significantly greater, as shown by the LFA (6.0%) and mechanical advantage (8.2%; p = 0.0078). By contrast, our results show that in the DO, the LRA was 2.4% longer and the muscular work was 10.4% greater (p = 0.0087).The mechanical advantage of the TM in BR subjects is significantly greater than in DO subjects. Moreover, this greater mechanical advantage may explain, at least in part, the higher incidence of temporomandibular dysfunctions in BR subjects.
- A radiological study on intra- and extra-cranial calcifications in adults with X-linked hypophosphatemia and associations with other mineralizing enthesopathies and childhood medical treatment. [Journal Article, Research Support, Non-U.S. Gov't]
- Orthod Craniofac Res 2016 May; 19(2):114-25.
1) The objective of this study was to explore radiological signs of intracranial and nuchal ligament calcifications in adult patients with X-linked hypophosphatemia (XLH) compared with controls and 2) to correlate signs of cranial calcifications in XLH patients with the presence of other extra-cranial enthesopathies, with the severity of skeletal XLH impact and with medical treatment during childhood.Lateral and postero-anterior cephalograms from 36 adult XLH patients and 49 adult controls and X-rays from spine, pelvis, knees and ankles from 31 of the 36 XLH patients.Radiological signs of intracranial and nuchal ligament calcifications in XLH patients were compared with controls by Fischer's exact test. In XLH patients, the presence of cranial calcifications was correlated with the presence of other enthesopathies, with the severity of skeletal XLH impact and with medical treatment by Fischer's exact or chi-squared test.Six (17%) XLH patients revealed major signs of intracranial calcifications. Nuchal ligament calcifications were common in XLH patients compared with controls (p = 0.018). Enthesopathy was present at 0-24 sites per XLH patient (median 2). Intracranial calcifications trended to correlate positively with vertebral enthesopathies (p = 0.059). Nuchal calcifications correlated positively with the severity of skeletal XLH impact (p = 0.040). Vertebral enthesopathies correlated negatively with medical treatment (p = 0.008).More XLH patients than controls showed nuchal ligament calcifications, and some XLH patients showed intracranial calcifications. Severely affected XLH patients often had nuchal ligament calcifications. Medically treated XLH patients had few vertebral enthesopathies.
- Primary tooth size asymmetry in twins and singletons. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):145-53.
To explore asymmetry values of antimeric deciduous tooth crown dimensions in three types of twins: monozygotic (MZ), dizygotic same-sex (DZ) and opposite-sex (OS) vs. single-born controls.Mesiodistal and labio-lingual crown dimensions of second deciduous molars and mesiodistal canine and first molar crown dimensions of 2159 children at 6-12 years of age were evaluated, originating from the US cross-sectional Collaborative Perinatal Study from the 1970s, including altogether MZ (n = 28), DZ same-sex (n = 33) and OS (n = 39) pairs. Single born (n = 1959) were used as controls.Dental casts were measured for comparison of variance relationships calculated from antimeric teeth, exhibiting fluctuating (FA), and directional (DA) asymmetry using anova.Significant differences appeared in MZ and OS girls in DA of deciduous canines, which gain size in the first and second trimester, and deciduous second molars, which finally stop crown growth during the early post-natal period. Significantly, increased FA values appeared for lower deciduous canines and second molars, indicating greatest environmental stress in OS girls, MZ girls and DZ boys. Twin girls had more fluctuating and directional crown asymmetry than twin boys, but in some dimensions, the twins were more symmetric than controls.Transmembrane hormonal influence between opposite-sex twins, and late gestational stress factors, caused by placental malfunction and/or monochorionicity, may be involved in asymmetric growth of antimers, during critical periods of crown size gain.
- Effect of organic solvents and ultrasound on the removal of orthodontic brackets. [Journal Article]
- Orthod Craniofac Res 2016 Aug; 19(3):137-44.
To evaluate the effect of organic gel solvents (70% acetone and 90% ethanol) and ultrasound in the removal of metallic brackets.Metallic brackets were bonded with light-cured orthodontic composite (Transbond XT) in 120 human bicuspids and divided into 6 groups for the enamel etch-and-rinse adhesive system (XT) and 6 groups to self-etching system (SEPT) according to pretreatment to removal test: control, 70% acetone, 90% ethanol, ultrasound, 70% acetone+ultrasound, and 90% ethanol+ultrasound. The brackets were subjected to removal by shear testing and Adhesive Remnant Index (ARI) evaluation. Some specimens were prepared and its adhesive interface and etching ability observed by scanning electron microscopy (SEM).Only the factor 'ultrasound' and its interaction with 'adhesive' were detected as a source of variance, with the SEPT/ultrasound showing the lowest shear strength than the other groups. Regardless the factor 'ultrasound', XT showed a higher ARI than SEPT; however, when the solvents were used, no differences were detected between XT and SEPT.The organic solvents were not effective in reducing shear bond strength. The etch-and-rinse adhesive system showed a higher and more favorable ARI score than the self-etching primer. The behavior of the organic solvents on ARI showed to be better when associated with the self-etching primer. The ultrasound was effective in reducing the shear bond strength of the self-etching adhesive system but not in affecting the ARI of the adhesive systems.
- Biomechanical characteristics of self-ligating brackets in a vertically displaced canine model: a finite element analysis. [Journal Article]
- Orthod Craniofac Res 2016 May; 19(2):102-13.
The objective of this study was to compare the biomechanical characteristics between two types of self-ligating brackets and conventional metal brackets using finite element analysis of a vertically displaced canine model focusing on the desired force on the canine and undesirable forces on adjacent teeth.Three-dimensional finite element models of the maxillary dentition with 1-mm, 2-mm, and 3-mm vertically displaced canines were constructed. Two different self-ligating brackets (In-Ovation C and Smart clip) and a conventional metal bracket (Micro-arch) were modeled. After a 0.016-inch NiTi (0.40 mm, round) wire was engaged, the displacement of each tooth was calculated using x-, y-, and z-coordinates, and the tensile and compressive stresses were calculated.The extrusion and maximal tensile stress of the canine differed little between the three brackets, but the intrusion and minimal compressive stress values of the adjacent teeth differed considerably and were highest in the Smart clip and least in the In-Ovation C. The extrusion and maximal tensile stress of the canine in the 3-mm displacement model was less than that in the 2-mm displacement model, and the intrusion and minimal compressive stress of the adjacent teeth increased with the degree of displacement.Self-ligating brackets were not superior to conventional brackets in leveling a vertically displaced canine. A continuous arch wire may not be recommended for leveling of severely displaced canines whether using self-ligating or conventional brackets.