Rehabilitative treatment of cleft lip and palate: experience of the Hospital for Rehabilitation of Craniofacial Anomalies/USP (HRAC/USP) – part 4

Treatment of patients with cleft lip and palate is completed with fixed prostheses, removable, total, implants and aims to restore aesthetics, phonetics and function and should be guided by the basic principles of oral rehabilitation, such as physiology, stability, aesthetics, hygiene and the expectations of the patient. In order to obtain longevity of a prosthetic rehabilitation, the periodontal and dental tissue as well as the biomechanics of the prosthesis are to be respected. The purpose of this article is to describe the types of prosthetics treatment, which are performed at HRAC/USP for the rehabilitation of cleft area in adult patients.

Craniofacial morphology in complete unilateral cleft lip and palate patients consecutively treated with 1-stage repair of the cleft

OBJECTIVE: To retrospectively evaluate the craniofacial morphology of children with a complete unilateral cleft lip and palate treated with a 1-stage simultaneous cleft repair performed in the first year of life. METHODS: Cephalograms and extraoral profile photographs of 61 consecutively treated patients (42 boys, 19 girls) who had been operated on at 9.2 (SD, 2.0) months by a single experienced surgeon were analyzed at 11.4 (SD, 1.5) years. The noncleft control group comprised 81 children (43 boys and 38 girls) of the same ethnicity at the age of 10.4 (SD, 0.5) years. RESULTS: In children with cleft, the maxilla and mandible were retrusive; the palatal and mandibular planes were more open, and sagittal maxillomandibular relationship was less favorable in comparison to noncleft control subjects. Soft tissues in patients with cleft reflected retrusive morphology of hard tissues--subnasal and supramental regions were less convex, profile was flatter, and nasolabial angle was more acute relative to those of the control subjects. CONCLUSIONS: Craniofacial morphology after 1-stage repair was deviated in comparison with noncleft control subjects. However, the degree of deviation was comparable with that found after treatment with alternative surgical protocols.

The genetic basis of craniofacial and dental abnormalities

The embryonic head development, including the formation of dental structures, is a complex and delicate process guided by specific genetic programs. Genetic changes and environmental factors can disturb the execution of these programs and result in abnormalities in orofacial and dental structures. Orofacial clefts and hypodontia/ oligodontia are examples of such abnormalities frequently seen in dental clinics. An insight into the mechanisms and genes involved in the formation of orofacial and dental structures has been gradually gained by genetic analysis of families and by the use of experimental vertebrate models such as the mouse and chick models. The development of novel clinical therapies for orofacial and dental pathological conditions depends very much on a detailed knowledge of the molecular and cellular processes that are involved in head formation.

A longitudinal three-center study of craniofacial morphology at 6 and 12 years of age in patients with complete bilateral cleft lip and palate

In this longitudinal study, the craniofacial morphology and evaluated soft tissue profile changes, at 6 and 12 years of age in patients with complete bilateral cleft lip and palate (CBCLP) were compared. Lateral cephalograms from 148 patients with CBCLP, treated consecutively at three European cleft centers, Gothenburg (n (A) = 37), Nijmegen (n (B) = 26), and Oslo (n (C) = 85), were evaluated. Eighteen hard tissue and ten soft tissue landmarks were digitized. Paired t test, Pearson's correlation coefficients, and multiple regression models were applied for statistical analysis. ANOVA and Tukey-B, as a post hoc test, were used to evaluate the increments and compare centers. Hard and soft tissue data were superimposed using the generalized Procrustes analysis. For Nijmegen, the increments of the variables SNA, ANB, SN-NL, SN-ML, NL-ML, Snss, and Snpg were significantly different than the two other centers (p = 0.041 to <0.001). SNPg increments were significantly different between Nijmegen and Oslo (p = 0.002). The three cleft centers followed different treatment protocols, but the main differences in craniofacial morphology until 12 years of age were the growth pattern and the maxillary and upper incisor variables. Follow-up of these patients until facial growth has ceased, which may elucidate components for improving treatment outcome.

Primate Craniofacial Function and Biology

Book review: Primate Craniofacial Function and Biology

Pediatric craniofacial trauma

PURPOSE: Maxillofacial and skull fractures occur with concomitant injuries in pediatric trauma patients. The aim of this study was to determine the causes and distributions of maxillofacial and skull fractures as well as concomitant injuries of pediatric patients in Switzerland. Results were compared with worldwide studies. MATERIALS AND METHODS: A retrospective review was conducted of 291 pediatric patients with maxillofacial and skull fractures presenting to a level-I trauma center over a 3-year span. Data concerning the mechanism of the accident and the topographic location of the injuries were analyzed. RESULTS: The most common causes were falls (64%), followed by traffic (22%) and sports-related accidents (9%). Fifty-four percent of the fractures occurred in the skull vault and 37% in the upper and middle facial third. One third of the patients (n = 95) suffered concomitant injuries, mostly cerebral concussions (n = 94). CONCLUSIONS: The spectrum of craniofacial injuries is related to the specific developmental stage of the craniofacial skeleton. It is probable that national prevention programs will have a positive effect on reducing the incidence of falls. Standardization of studies is needed for international comparison.

Does hyoid bone resection according to Sistrunk influence normal craniofacial growth? A cephalometric study

PURPOSE: To retrospectively evaluate the influence of hyoid bone resection according to Sistrunk in early age due to a thyroglossal duct cyst on craniofacial growth. MATERIALS AND METHODS: We retrospectively examined 10 patients (2 females and 8 males) having had hyoid bone resection according to Sistrunk due to thyroglossal duct cysts by lateral cephalograms taken before orthodontic treatment (mean, 17.1 years; range, 8.6-31.9 years). Surgery was carried out at a mean age of 4.4 years (range, 0.37-9.8 years). All lateral cephalograms were evaluated and traced by hand. Descriptive statistics were calculated, and data from each patient were compared individually with corresponding standard values (age and gender) from Bathia and Leighton. RESULTS: With regard to sagittal parameters, the SNB angles were by trend too small and the ANB angles were too large. However, the ratio of mandibular to maxillary length showed that the patients had a mandible that was too large or maxilla that was too small. With regard to vertical parameters, large deviations from normal values in both directions (hyperdivergent to hypodivergent pattern) could be detected when we analyzed NSL/ML', NL/ML', and NSL/NL. With regard to dental parameters, the majority of the patients had retroclined upper (IsL/NL, IsL/N-A) and lower (IiL/ML, IiL/N-B) incisors. CONCLUSIONS: Several vertical and horizontal skeletal and dental cephalometric parameters were shown to be different by trend when compared with control values. A possible negative impact on craniofacial growth potential and direction as a result of hyoid resection in early age according to Sistrunk cannot be excluded.

Pre-clinical in vivo models for the screening of bone biomaterials for oral/craniofacial indications: focus on small-animal models.

Preclinical in vivo experimental studies are performed for evaluating proof-of-principle concepts, safety and possible unwanted reactions of candidate bone biomaterials before proceeding to clinical testing. Specifically, models involving small animals have been developed for screening bone biomaterials for their potential to enhance bone formation. No single model can completely recreate the anatomic, physiologic, biomechanic and functional environment of the human mouth and jaws. Relevant aspects regarding physiology, anatomy, dimensions and handling are discussed in this paper to elucidate the advantages and disadvantages of small-animal models. Model selection should be based not on the 'expertise' or capacities of the team, but rather on a scientifically solid rationale, and the animal model selected should reflect the question for which an answer is sought. The rationale for using heterotopic or orthotopic testing sites, and intraosseous, periosseous or extraskeletal defect models, is discussed. The paper also discusses the relevance of critical size defect modeling, with focus on calvarial defects in rodents. In addition, the rabbit sinus model and the capsule model in the rat mandible are presented and discussed in detail. All animal experiments should be designed with care and include sample-size and study-power calculations, thus allowing generation of meaningful data. Moreover, animal experiments are subject to ethical approval by the relevant authority. All procedures and the postoperative handling and care, including postoperative analgesics, should follow best practice.

One-stage (Warsaw) and two-stage (Oslo) repair of unilateral cleft lip and palate: Craniofacial outcomes

The aim of this study was to compare facial development in subjects with complete unilateral cleft lip and palate (CUCLP) treated with two different surgical protocols. Lateral cephalometric radiographs of 61 patients (42 boys, 19 girls; mean age, 10.9 years; SD, 1) treated consecutively in Warsaw with one-stage repair and 61 age-matched and sex-matched patients treated in Oslo with two-stage surgery were selected to evaluate craniofacial morphology. On each radiograph 13 angular and two ratio variables were measured in order to describe hard and soft tissues of the facial region. The analysis showed that differences between the groups were limited to hard tissues – the maxillary prominence in subjects from the Warsaw group was decreased by almost 4° in comparison with the Oslo group (sella-nasion-A-point (SNA) = 75.3° and 79.1°, respectively) and maxillo-mandibular morphology was less favorable in the Warsaw group than the Oslo group (ANB angle = 0.8° and 2.8°, respectively). The soft tissue contour was comparable in both groups. In conclusion, inter-group differences suggest a more favorable outcome in the Oslo group. However, the distinctiveness of facial morphology in background populations (ie, in Poles and Norwegians) could have contributed to the observed results.

The functions of pitx2 and Bmp signaling in craniofacial development

The formation of the vertebrate face is an extremely complex developmental process, which needs to coordinate the outgrowth of several facial primordia. Facial primordia are small buds made up of mesenchymal masses enclosed by an epithelial layer that surrounds the primitive mouth. The upper jaw is formed by the maxillary process, the lateral nasal process, and the frontonasal process while the mandibular process forms the lower jaw. Recent experiments using genetics in mice and bead implantation approaches have shown that the pitx2 homeobox gene and Bmp signaling play important roles in this complex developmental process. However, the molecular mechanisms underlying the function of pitx2 and Bmp in these events are still unclear. Here, we show that pitx2 is required for oral epithelium maintenance, and branchial arch signaling is pitx2 dosage sensitive by using pitx2 allelic combinations that encode varying levels of pitx2. Maintenance of fgf8 signaling requires only low pitx2 dosage while repression of Bmp signaling requires high pitx2 levels. Different incisor and molar phenotypes in low level pitx2 mutant embryos suggest a distinct requirement for pitx2 in tooth-type development. The results show that pitx2 is required for craniofacial muscle formation and expanded Bmp signaling results in excess bone formation in pitx2 mutant embryos. Fate-mapping studies show that ectopic bone results from excessive bone growth, instead of muscle transformation. Moreover, by using cre/loxp system we show that partial loss of Bmpr-IA in the facial primordia results in cleft lip/palate, abnormal teeth, ectopic teeth and tooth transformation. These phenotypes suggest that Bmp signaling has multiple functions during craniofacial development. The mutant palate shelves can fuse with each other when cultured in vitro, suggesting that cleft palate is secondary to the partial loss of Bmpr-IA. Furthermore, we prove that Bmp4, one of the ligands of Bmpr-IA, plays a role during lip fusion developmental process and partial loss of Bmp4 in the facial primordia results in the lip fusion delay. These results have provided insight to understand the complex signaling cascades that regulate craniofacial development. ^