Three-dimensional facial surface analysis of patients with skeletal malocclusion.

Three-dimensional (3D) laser surface scanning analysis has taken hold in orthodontics, as well as craniomaxillofacial and plastic surgery as a new tool that can navigate away from the limitations of conventional two-dimensional methods. Various techniques for 3D reconstruction of the face have been used in diagnosis, treatment planning and simulation, and outcomes follow-up. The aim of the current prospective study was to present some technical aspects for the assessment of facial changes after orthodontic and orthognathic surgery treatment using 3D laser surface scanning. The technique proposed for facial surface shape analysis represented three-dimensionally the expected surgical changes, and the reduction of the postoperative swelling was verified. This study provides technical information from the data collection to the 3D virtual soft-tissue analysis that can be useful for diagnostic information, treatment planning, future comparisons of treatment stability or facial postoperative swelling, and soft-tissue profile assessment.

Three-dimensional cephalometric study of upper airway space in skeletal class II and III healthy patients.

Because the pharynx and the dentofacial structures have close relationship, a mutual interaction can be expected to occur between them. The literature presents skeletal malocclusion as etiology for airway morphology changes and/or vice versa. The present three-dimensional cephalometric study from computed tomography scans was carried out to investigate upper airway space in normal nasal breathing patients presenting skeletal pattern of classes II and III. In addition, the statistical analysis was done according to gender criterion. The results revealed that the majority of the airway measurements have not been affected by type of malocclusion. The three-dimensional technology used in this study also allowed the volume and surface area calculations, and no statistical significance was found. The retroglossal width and posterior nasal cavity height mean were larger in males than females in the class II group, but volume and cross-section area were not statistically significant. However, in class III group, although the differences in linear and angular measures means were not significant, the retropalatal volume and retroglossal volume and cross-section area were larger in males. The authors highlight that the evaluation of upper airway space should be an integral part of diagnosis and treatment planning to achieve functional balance and stability of the results.

How the lower face soft tissue changes after mandibular advancement or setback.

To contribute as an auxiliary tool for orthodontic and orthognathic planning and treatment, short-term changes on the lower face soft and hard tissues were investigated. All subjects presented adequate maxillary relation with the cranial base. The treatment was done by mandibular advancement in patients with skeletal class II or setback in skeletal class III, by the same oral surgeon, using the same technique, and rigid internal fixation. Lateral cephalograms were traced at the following intervals: T0--immediately before the surgical procedure, T1--6 months after surgery, and T2--1 year after surgery. The postoperative data of the lower face revealed highly significant changes for the soft tissue pogonion and lower lip, in the mandible advancement cases, whereas the underlying bone and dental structures remained constant. For the mandible setback cases, just the hard tissue pogonion variable displayed a statistically significant change.

Cranial base angulation in Brazilian patients seeking orthodontic treatment.

The relationship between cranial base flexion and facial prognathism has been of interest to orthodontists, orthognathic maxillofacial surgeons, and plastic surgeons. This study aimed to identify the cranial base flexion of adults with anteroposterior skeletal disharmony. Because the sample was representing a mixed racial population, the authors performed an investigation to confirm an association with other researches performed in different parts of the world. The results revealed an increase in the cranial base flexion in cases diagnosed as class II skeletal pattern and reduction in the group with class III skeletal pattern. These findings suggested that the characteristics of the Brazilian cases did not differ from some other studies despite various influences of different ethnicities in that population.

Treatment protocol to control Streptococcus mutans level in an orthodontic patient with high caries risk.

The purpose of this article is to report a protocol for treating an orthodontic patient with a high risk of developing caries. The salivary level of Streptococcus mutans was evaluated during various stages of orthodontic treatment. It was significantly high before professional application of 1% chlorhexidine collagen gel, daily mouth rinsing with 0.05% sodium fluoride solution, and bonding of the bands and brackets. Although there were no other changes in hygiene habits, microbiologic tests showed that the microbiota was in balance during the follow-up periods. At the end of orthodontic treatment, periodontal health was observed, and enamel surfaces showed signs of remineralization.

A protocol for cranial base reference in cephalometric studies.

Establishment of the cranial base references and the coordinate system is important for measurement of events occurring on the face. The literature suggests that the horizontal axis is obtained by tracing a line in clockwise direction at seven degrees from the Sella-Nasion line, and the vertical axis is perpendicular to this former axis passing through the Sella point. However, could this standardization better represent the angle between the Sella-Nasion line and Frankfort Horizontal Plane in a Brazilian population and be employed in cephalometric studies? Thus, the present study had two purposes: to identify the cranial base inclination in adult patients presenting with intermaxillary anteroposterior skeletal disharmony and to evaluate the reliability of a protocol to reproduce the cranial base reference. Lateral cephalograms of three different times were traced: T0) onset of orthodontic treatment and immediately before the orthognathic surgery, T1) six months after surgery, and T2) one year after surgery. The results displayed a mean cranial base inclination of 7.91 degrees. Variation of the intraindividual data allowed the conclusion that the protocol proposed by utilization of an individual template of the cranial base reference was effective for the exactness of measurements in cephalometric studies.

Three-dimensional computerized orthognathic surgical treatment planning.

Three-dimensional volumetric imaging allows better visualization of the morphologic deformity, planning the surgical approach, and evaluating the response not visualized previously with two-dimensional dentofacial records. This in time will replace conventional two-dimensional cephalometric planning and plaster cast model surgery. Three-dimensional craniofacial imaging requires application of various techniques from applied mathematics, computer sciences, and bioengineering. Although it is today in its infancy, it has the potential to accurately simulate the operative experience for surgical planning, with improved morphologic outcomes, patient-specific biomechanical modeling to allow functional assessment of the various outcomes, and accurate simulation for surgical resident training.

Single median maxillary central incisor: new data and mutation review.

BACKGROUND: Single median maxillary central incisor (SMMCI) is a rare anomaly that may occur alone or associated with other conditions, frequently as part of the holoprosencephaly (HPE) spectrum. However, it has been suggested that SMMCI alone, or associated with some midline defects, may be considered a different entity from HPE (OMIM: 147250). Families with SMMCI, without HPE cases, are difficult to counsel for the risk of HPE in future generations because the same midline defects described as part of the "SMMCI syndrome" can also be part of the HPE spectrum. METHODS: We screened five cases of SMMCI for mutations in three HPE genes, SHH, TGIF, and SIX3. RESULTS: A missense mutation c.686C>T was found in the gene SIX3 of one patient, which did not differ from the accepted 20% of known HPE gene mutations among all HPE cases. Our results and an extensive literature review of gene mutations in patients with SMMCI showed that 27/28 of them were in HPE genes: SHH (n = 21), SIX3 (n = 3), TGIF (n = 1), GLI2 (n = 1), and PTCH (n = 1), and only one in the SALL4 gene. CONCLUSIONS: The clinical findings in patients with SMMCI without HPE in families with mutations in HPE genes cannot be distinguished from the findings reported in the SMMCI syndrome. Therefore, persons with SMMCI and their relatives should be carefully investigated for related midline disorders, especially of the HPE spectrum, and all known HPE genes screened.

Hypersensitivity to metals in orthodontics.

To study the incidence of hypersensitivity to orthodontic metals, patch tests were carried out before and 2 months after the placement of orthodontic appliances in 38 patients (17 male, 21 female). The tested substances were cobalt chloride, copper sulfate, potassium dichromate, iron sulfate, manganese chloride, molybdenum salt, nickel sulfate, and titanium oxide. Eight strips containing the test substances were positioned on the patients' backs. They were removed after 48 hours and assessed by a dermatologist at 48 and 72 hours after antigen application. The obtained data were analyzed by the chi-square test and McNemar's chi-square test. Statistically significant positive reactions were observed for nickel sulfate (21.1%), potassium dichromate (21.1%), and manganese chloride (7.9%); reactions to nickel sulfate had the greatest intensity. No differences were observed between the reactions before and after placement of the orthodontic appliances; this indicates that they did not sensitize the patients or affect their tolerance to these metals during the study period. No statistical difference was observed regarding sex for any evaluated substance, although a greater tendency to positivity to nickel sulfate was observed among female patients and to potassium dichromate in male patients.