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Results for “Maxillofacial Abnormalities”

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PubMed1995

[The pathogenesis of and treatment principles in functional overload of the periodontium].

A total of 4864 patients (2810 women and 2054 men) aged 16 to 64 with maxillofacial abnormalities and 3686 patients (2283 women and 1403 men) aged 18 to 64 with dentition defects were examined. 2624 patients aged 19 to 62 were admitted for orthodontic treatment. Experiments on 96 dogs were carried out. Pathologic changes in the periodontal tissue were detected in 3765 (77.4%) patients with maxillofacial abnormalities and in 2918 (78.8%) with dentition defects. The author considers that two major factors contribute to the pathogenesis of functional overstrain of the periodontium: change of occlusion loading of the teeth and reduced tolerance of periodontal tissues. Good results were attained in 92.7% of patients with functional overloading of the periodontium. Dog experiments demonstrated that overexercise of teeth may lead to changes in the periodontium, which are similar to tissue restructuring in orthodontic interventions. If the periodontium is weakened, an exacerbation of periodontitis develops. After stopping of functional overstrain--repair processes in the periodontal tissues of young animals, including repair of bone tissue take place.

Adolescent↗
PubMedDate not supplied

Utilization of 3-D computer tomographs in oral surgery.

Imaging is essential in the diagnosis and treatment of maxillofacial abnormalities. CT scans are but one type of imaging studies available to the practitioner. Computers have recently enhanced the traditional CT scan so that it can now be viewed in a three-dimensional reconstruction. Essentials of 3-D imaging and its uses will be presented by the authors, with various case reports to illustrate their value in the dental office.

Adolescent↗
PubMedDate not supplied

[Stickler syndrome: maxillo-facial abnormalities].

A case of Stickler syndrome (hereditary arthro-ophthalmo-dystrophy) with maxillo-facial abnormalities and colon atresia is reported. The authors emphasize that in Stickler syndrome, (a chondrodystrophy with congenital alteration of type II collagen) the maxillofacial abnormalities are consecutive to prosencephalic neural crests dysneurulation, which caused mesethmoidal dysneurulation (and consequently of frontonasal-premaxillary structures); eye and colon abnormalities are consecutive to rhombo-mesencephalic neural crests dysneurulation. The Authors hypothesize that genic mutation, responsible of enzymatic deficiency of the neural crest multipotent cells, caused a morphogenetic alteration of the fronto-naso-philtral structures of the midface and of low face structures.

Female↗
PubMedDate not supplied

[The classification of defects in the dental arches of children and orthodontic treatment methods].

Dentition defects occurring in children are classified into 6 classes with subclasses in some of them. Class I includes dentition with defects in the frontal part, class II includes dentitions with distal defects. Both classes include special subclasses for dentition with defects of deciduous teeth, of permanent teeth with underdeveloped roots, and of permanent teeth with mature roots. Non-distal dentition defects (class III) are divided into two subclasses: unilateral and bilateral. Class IV includes dentition with multiple defects in various age groups. Dentition defects combined with maxillofacial abnormalities, deformations, and defects are classified as class V. Primary hypo- and anodontia are referred to class VI. Indications to fitting with removable plate prostheses, permanent bridge prostheses, and prosthetic devices of various design to repair the defects of various localization, extent, and the degree of development of the maxillofacial area are defined. Special attention is paid to fixation of prostheses, the most intricate problem in prostheses of dentition defects in children. The suggested classification is practically important for the diagnosis and planning of orthodontic treatment of children with dentition defects.

Activator Appliances↗
PubMed2003

The role of oral appliances in treating obstructive sleep apnea.

BACKGROUND: Sleep-related breathing disorders are common and often are associated with vascular complications such as arterial hypertension, coronary heart disease and stroke. The most widely studied form of these disorders is obstructive sleep apnea. Patients usually are diagnosed with obstructive sleep apnea years after the onset of symptoms, which generally are nonspecific and include excessive daytime sleepiness, chronic fatigue and habitual snoring. The risk factors for sleep apnea are obesity, advancing age, male sex and maxillofacial abnormalities. This review focuses on the diagnosis and treatment of obstructive sleep apnea and, specifically, on the utility of oral appliances in the management of this disorder. METHODS: The review is based on a MEDLINE search for articles in English on this topic. The article discusses results of randomized studies and prospective case series. CLINICAL IMPLICATIONS: Several treatment options are quite effective. Nasal continuous positive airway pressure, with an overall acceptance rate of 70 percent, is the most widely used treatment modality. Maxillofacial surgery, although effective, is reserved for patients who have not responded to the more conventional therapies. Newer methods include application of oral appliances. Oral appliances have been shown to alleviate the severity of respiratory disturbances during sleep by about 60 percent, with an overall acceptance rate of 75 percent. The long-term complications generally are minor and are related to occlusal changes and temporomandibular joint discomfort. CONCLUSIONS: With the advent of oral appliances, dentists are increasingly involved in managing the care of patients with sleep-related breathing disorders. Further studies are needed to determine the long-term complications of this type of intervention for the treatment of sleep-related breathing disorders.

Adult↗
PubMed2003

Development of a new poly(dimethylsiloxane) maxillofacial prosthetic material.

Maxillofacial prosthetic materials are used to rehabilitate patients suffering from acquired or congenital facial disfigurement. Silicone rubber materials [poly(dimethylsiloxane) rubbers] are the materials of choice. However, current formulations have inadequate mechanical properties, in particular, tear strength. The purpose of this study was to formulate a new poly(dimethylsiloxane) material with improved mechanical properties in comparison to commercially available materials. The formulations developed were based on condensation chemistry containing a hydroxy-end-blocked poly(dimethylsiloxane), hydrophobic silica filler, silane cross-linking agents, and a tin catalyst. The following parameters were varied in order to formulate improved materials: (a) bimodal polymeric mix (i.e., ratio of high- and low-molecular-weight polymers); (b) silica filler type and quantity. By varying these parameters a formulation was developed with a base polymer mix of 80%:20% high- to low-molecular-weight polymers into which 20% w/w filler was added. This formulation had a tear strength of 22.23 +/- 1.6 m N/mm compared to the commercial materials having tear strengths in the range 4.53-17.63 N/mm.

Biocompatible Materials↗
PubMed2005

High-dose retinoic acid modulates rat calvarial osteoblast biology.

Retinoic acid has been shown to adversely affect craniofacial development. Cleft palate and craniosynostosis are two examples of craniofacial defects associated with prenatal exposure to this agent. Although the effects of retinoic acid on cephalic neural crest-derived tissues have previously been studied, the specific effects of retinoic acid on the cellular biology of osteoblasts remain unclear. The purpose of this study was to analyze in detail the effects of pharmacologic doses of retinoic acid on the differentiation and proliferation of osteoblasts derived from an intramembranous source. Primary rat calvarial osteoblasts were established in culture and treated with 1 or 10 microM all-trans-retinoic acid. Retinoic acid treatment markedly increased expression of osteopontin up to 48 h after stimulation. Consistent with this early stage of differentiation, both mRNA and protein analysis of FGF receptor isoforms demonstrated a switch in predominance from fibroblast growth factor receptor 2 (fgfr2) to fgfr1. Analysis of PCNA protein confirmed inhibition of proliferation by retinoic acid. To determine whether these alterations in osteoblast biology would lead to increased differentiation, we examined short term [alkaline phosphatase (AP) activity] and long term (von Kossa staining) surrogates of bone formation in vitro. These assays confirmed that retinoic acid increased osteogenesis, with a 4-fold increase in bone nodule formation in cells treated with 10 microM retinoic acid after 28 days. Overall, our results demonstrated that pharmacologic doses of all-trans-retinoic acid decreased osteoblast proliferation and increased differentiation, suggesting that retinoic acid may effect craniofacial development by pathologically enhancing osteogenesis.

Alkaline Phosphatase↗
PubMed1997

[Osteoinduction and -reparation].

Traumata, diseases, developmental deformities, and tumor resections frequently cause bone defects and atrophies. In general, three different mechanisms exist by which bone restoration can be achieved: (1) osteogenesis initiated by vital, osteoblastic cells of autografts; (2) osteoconduction (or creeping substitution); and (3) osteoinduction. The latter mechanism means the differentiation of pluripotent, mesenchymal-type cells (located in a recipient bed with strong regenerative capacity) into cartilage- and bone-forming progenitor cells under the influence of inductive bone morphogenetic proteins (BMPs). Some BMPs are physiologically included in low concentrations as organic components in bone tissue. They can diffuse from demineralized bone implants into the recipient bed and induce a differentiation into new bone tissue. Nine different BMPs have been isolated, characterized, and cloned. Some of these possess inductive properties and can initiate new bone formation in muscle tissue or in bone defects. In the future recombinant BMPs will be available in unlimited quantities. This will lead to completely new therapeutic concepts in reconstructive bone surgery.

Animals↗
PubMed2004

Orofacial development in children with Down's syndrome 12 years after early intervention with a stimulating plate.

BACKGROUND: Orofacial regulation therapy for children with Down's syndrome was introduced to Europe in Munich in 1978. Since then, many clinical studies have provided scientific evidence that this therapeutic approach enhances the orofacial function and facial appearance of children with trisomy 21. Only few long-term results have been published to date. PATIENTS AND RESULTS: In the present study, 20 children with trisomy 21 were examined more than 12 years after starting treatment in infancy with a Castillo Morales stimulating plate. The follow-up examination showed that the improved orofacial appearance resulting from the early treatment had remained stable in most cases. Although the mechanical stimulus of the stimulating plate was absent during the follow-up period, some patients revealed a lip and tongue posture superior to that recorded at baseline. CONCLUSION: According to the results of the present study, the orofacial status in early childhood is decisive for the subsequent development of the orofacial region and the long-term stability of the achieved improvements: Children with a pronounced orofacial dysfunction showed a greater stimulation-plate-induced improvement than those with initially moderate orofacial findings. This observation was confirmed by the findings of the 12-year follow-up: Children with Down's syndrome and initially slight orofacial impairment displayed only slight improvements or unchanged findings.

Adolescent↗
PubMed2004

[Rapid prototyping in planning reconstructive surgery of the head and neck. Review and evaluation of indications in clinical use].

PURPOSE: The aim was to define the indications for use of rapid prototyping models based on data of patients treated with this technique. PATIENTS AND METHODS: Since 1987 our department has been developing methods of rapid prototyping in surgery planning. During the study, first the statistical and reproducible anatomical precision of rapid prototyping models was determined on pig skull measurements depending on CT parameters and method of rapid prototyping. RESULTS: Measurements on stereolithography models and on selective laser sintered models confirmed an accuracy of +/-0.88 mm or 2.7% (maximum deviation: -3.0 mm to +3.2 mm) independently from CT parameters or method of rapid prototyping, respectively. With the same precision of models multilayer helical CT with a higher rate is the preferable method of data acquisition compared to conventional helical CT. From 1990 to 2002 in atotal of 122 patients, 127 rapid prototyping models were manufactured: in 112 patients stereolithography models, in 2 patients an additional stereolithography model, in 2 patients an additional selective laser sinter model, in 1 patient an additional milled model, and in 10 patients just a selective laser sinter model. CONCLUSION: Reconstructive surgery, distraction osteogenesis including midface distraction, and dental implantology are proven to be the major indications for rapid prototyping as confirmed in a review of the literature. Surgery planning on rapid prototyping models should only be used in individual cases due to radiation dose and high costs. Routine use of this technique only seems to be indicated in skull reconstruction and distraction osteogenesis.

Computer Graphics↗
PubMed1993

Nasopharyngeal carcinoma. Computed tomographic imaging of four cases.

Nasopharyngeal carcinoma occurs with great frequency in Asia. It is an infiltrative tumor that often produces no symptoms early in its course. However, the proximity of the nasopharynx to the nasal cavity, eustachian tubes, masticatory muscles, and cranial nerves can allow extension of the lesion into these structures, resulting in numerous maxillofacial abnormalities. Computed tomography is effective in imaging the development of nasopharyngeal carcinoma in the nasopharynx as well as the subsequent spread of the neoplasm to adjacent areas. Four cases of nasopharyngeal carcinoma are presented in which computed tomography provides an accurate assessment of the extent of the tumor and allows correlation with clinical manifestations.

Adult↗
PubMed1998

Simultaneous malaroplasty with porous polyethylene implants and orthognathic surgery for correction of malar deficiency.

PURPOSE: Patients with skeletal malrelationships caused by maxillary anteroposterior defect and midface hypoplasia may present with an alteration of cheekbone contour. High osteotomies, segmental osteotomies of the zygomatic complex, and malar expansion with alloplastic materials can be performed to improve facial aesthetics. This article describes the restoration of cheekbone-nasal base-lip contour by performing a malaroplasty using an alloplastic implant in addition to orthognathic surgery. PATIENTS AND METHODS: From 1995 to 1996, 17 patients with maxillomandibular malrelationships and deficient cheekbone contour were tested by malar augmentation with porous high-density polyethylene in association with maxillary advancement and mandibular setback. The diagnosis of cheekbone contour alteration was made after observing the patient from a lateral, frontal, and oblique point of view. The position of the implant was determined by using Mladick's point, with lateral or medial extension in relation to the depressed area. RESULTS: By the restoration of normal cheekbone-nasal base-upper lip contour produced excellent aesthetic results in all patients. CONCLUSIONS: Malaroplasty in association with bimaxillary orthognathic surgery seems to be an effective procedure for treating midface skeletal deficiencies.

Biocompatible Materials↗
PubMed2000

Long-term stability of surgical open-bite correction by Le Fort I osteotomy.

Skeletal changes greater than those observed in untreated adults have been noted beyond 1 year post-surgery in adult patients who had surgical correction of a long face deformity. The stability of skeletal landmarks and dental relationships from 1 to >3 years post-surgery was examined in 28 patients who had undergone surgery of the maxilla only, and in 26 patients who had undergone 2-jaw surgery to correct >2 mm anterior open bite. Although the average changes in almost all landmark positions and skeletal dimensions were less than 1 mm, point B moved down >2 mm and face height increased >2 mm in one-third of the maxilla-only group and in 40% of the 2-jaw group (>4 mm in 10% and 22% respectively). Overbite decreased 2-4 mm in only 7% of the maxilla-only and 12% of the 2 groups, with no changes >4 mm, because in three-fourths of the patients with an increase in anterior face height, further eruption of the incisors maintained the overbite relationship. In the maxilla-only group, mandibular length (Co-Pg) showed >2 mm long-term change in 45% of the patients, two-thirds of whom showed an increase rather than a decrease in length. In the 2-jaw group, no patients showed a decrease in Co-Pg length and one-third had an increase. For both groups, changes in overjet were smaller and less frequent than changes in mandibular length.

Adaptation, Physiological↗
PubMed2005

Midfacial and mandibular morphometry of children with Class II and Class III malocclusions.

There is insufficient evidence in conventional cephalometric analysis of the actual sites of putative maxillofacial change in Class II and Class III malocclusions. The purpose of this study was to provide more information about the morphological characteristics of the midfacial complex and mandible in children with Class II or III malocclusions. Seventy children with Class II, division 1 malocclusion and 70 children with Class III malocclusion were compared with 70 children with normal occlusion. This study was conducted to carry out geometric morphometric assessments to localize alterations using Procrustes analysis and thin-plate spline analysis. Procrustes analysis indicated the midfacial and mandibular morphologies differed between normal occlusion subjects and subjects with Class II or Class III malocclusion (P<0.0001). The deformations in subjects with Class II malocclusion may represent a developmental elongation of the palatomaxillary complex and a shortening of the mandible anteroposteriorly, which leads to the appearance of a protruding midface and retruding mandibular profile. In contrast, the deformations in subjects with Class III malocclusion may represent a developmental shortening of the palatomaxillary complex and elongation of the mandible anteroposteriorly, which leads to the appearance of a retrognathic midface and prognathic mandibular profile.

Cephalometry↗
PubMed2005

Maxillofacial and dental manifestations in a patient with mandibulo-acral dysplasia.

Mandibulo-acral dysplasia (MAD) is a rare condition characterized by mandibular hypoplasia, acroosteolysis, delayed cranial suture closure, hypoplastic clavicles, stiff joints, dental crowding, atrophy of the skin of the hands and feet, progeroid facial appearance, alopecia and short stature. This report presents a patient with MAD, suffering from difficulty in mastication and speech, together with limited lip closure and aesthetic problems related to the clinical outcomes of the syndrome. The aim of reporting this case is to detail the first widely determined dental and maxillofacial abnormalities of a rare syndrome, mandibulo-acral dysplasia, and to contribute to the data regarding the etiology of consanguinity.

Adult↗
PubMed1995

Facial dimple with accessory bone and teeth.

Accessory jaws (distomus), with or without teeth, rarely occur. This condition has been observed most commonly in association with lateral facial clefts. A case of a 6-year-old child with a unilateral facial dimple which is interpreted as a putative vestige of a lateral facial cleft and accessory maxilla is reported. Possible aetiology is addressed and previous cases are reviewed.

Child↗