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PubMed2007

Fibula free flap for mandible reconstruction: analysis of 30 consecutive cases and quality of life evaluation.

The objectives of this study were to evaluate the use of fibula free flaps (FFF) for mandible reconstruction in patients with oral cavity cancer and to assess the quality of life (QOL) of the patients who underwent reconstructive surgery. Thirty patients with T(3), T(4) oral cavity carcinoma underwent surgical resection of the primary tumor infiltrating the mandible or primarily originating from the mandible. According to the length (less or more than 8 cm) and localization (anterior or posterior) of the mandibular defect, patients were subdivided into four groups. In all cases an osseoseptocutaneous FFF was chosen for postresective defect reconstruction. To reconstruct anterior mandibular defects, two osteotomies were needed to give the fibula a proper shape. For extended defects, the fibula usually required more than one osteotomy. Skin islands were designed based on Doppler cutaneous perforator findings. The fibular free skin islands remained viable in all patients and no partial or total skin loss was observed. In the majority of patients (87 percent) the facial artery was used for arterial anastomosis. In 6 month follow-ups, the QOL was evaluated as very good except for socioeconomic items. Pain was mild and incidental. Appearance and subjective feeling scores were excellent in two groups with mandibular defects smaller than 8 cm, although in patients with larger defects, they were still very good. Functional effects remained good, and they correlated with the size of defects. In contrast, social activities, recreation, and employment were below patients' expectations and generally reflected the current situation in Poland, but no correlation with the results of reconstruction was found. The present results show that osseocutaneous fibula free flap used in reconstructive surgery for cancer of the oral cavity allows more radical and aggressive resection with very good or excellent functional and aesthetic outcome. Estimated QOL seems an important part of evaluation of the treatment outcome.

Anastomosis, Surgical↗
PubMed2000

Kinesiographic study of the mandible in young patients with unilateral posterior crossbite.

It is generally assumed that children with posterior crossbites have abnormal mandibular movements; however, this assumption has not been clearly evaluated. The purpose of this investigation was to study the movements and the resting position of the mandible in 2 samples of 30 subjects, one aged 10 to 14 years with right posterior crossbite, the other aged 10 to 15 years with normal occlusion. Subjects in both groups exhibited a Class I skeletal relationship and mesofacial growth pattern. A mandibular kinesiograph was used to record both the mandibular resting position and dynamic movements. Mandibular movements were recorded during (1) maximum excursions (opening-closing, protrusion, right and left excursions), (2) swallowing, and (3) mastication. The results showed no differences between groups in the extension of the movements during closing and protrusion. However, crossbite patients exhibited a significant lateral shift during these movements. Right and left excursions were also similar between groups. The dimension of the freeway space was similar between groups, but the lateral shift found in centric occlusion was also present in the crossbite group when the mandible was at rest. The crossbite group more frequently showed a pattern of abnormal swallowing. No differences were found in any of the parameters studied during the masticatory cycle. There was no relationship between the side of the crossbite and the masticatory preference side. In conclusion, posterior crossbite patients showed a lateral shift in some movements that persisted when the mandible was at rest.

Adolescent↗
PubMed2003

Lateral functional shift of the mandible: Part I. Effects on condylar cartilage thickness and proliferation.

Lateral functional shift of the mandible is characterized by transverse rotation of the entire mandible about a vertical axis toward 1 side of the head. The effect of this shift is that the condyle on the side opposite the direction of the shift is displaced anteriorly, or protruded, while the condyle on the side toward the shift is more stable positionally and is likely to be slightly retruded. According to the view that growth of the mandibular condylar cartilage (MCC) adapts to its local functional-biomechanical environment, differential changes in metabolic activity of the MCC would be expected on the nonprotruded and the protruded sides. To evaluate this hypothesis, 21 rats (28 days old) were fitted with intraoral positioners designed to shift the mandibular postural position asymmetrically. Cartilage thickness and BrdU labeling index in the MCC 3, 7, and 14 days after placement of the positioners were compared with those in age-matched controls that received no positioners. Cartilage thickness in the MCC on the protruded side was significantly greater than that in the controls at each time interval, with the difference increasing slightly with time. The labeling index for the protruded MCC was significantly greater than the controls at both 7 and 14 days after positioner placement. Trends on the nonprotruded side were generally opposite, culminating in reduced thickness and proliferation after 14 days. Thickness and labeling index were greater on the protruded side at every time interval except 3 days (labeling index). These trends in cartilage thickness and proliferation are consistent with previous studies of MCC changes after bilateral functional protrusion or retrusion. These data suggest that changes in MCC thickness and proliferative activity might accompany a lateral functional shift of the mandible in growing persons.

Analysis of Variance↗
PubMed2005

An Early Pleistocene hominin mandible from Atapuerca-TD6, Spain.

We present a mandible recovered in 2003 from the Aurora Stratum of the TD6 level of the Gran Dolina site (Sierra de Atapuerca, northern Spain). The specimen, catalogued as ATD6-96, adds to the hominin sample recovered from this site in 1994-1996, and assigned to Homo antecessor. ATD6-96 is the left half of a gracile mandible belonging to a probably female adult individual with premolars and molars in place. This mandible shows a primitive structural pattern shared with all African and Asian Homo species. However, it is small and exhibits a remarkable gracility, a trait shared only with the Early and Middle Pleistocene Chinese hominins. Furthermore, none of the mandibular features considered apomorphic in the European Middle and Early Upper Pleistocene hominin lineage are present in ATD6-96. This evidence reinforces the taxonomic identity of H. antecessor and is consistent with the hypothesis of a close relationship between this species and Homo sapiens.

Adult↗
PubMed1993

Recently recovered Kenyapithecus mandible and its implications for great ape and human origins.

We report here a Kenyapithecus africanus juvenile mandible recovered from middle Miocene (ca. 14-16 million years) deposits of Maboko Island (Lake Victoria), Kenya. Symphyseal and dental attributes of the mandible distinguish K. africanus, a species widely regarded as the earliest known member of the great ape and human clade, from other Miocene large-bodied hominoids. The Maboko Island mandible exhibits a markedly proclined symphyseal axis, massive inferior transverse torus, mesiodistally narrow, high-crowned, and strongly procumbent lateral incisor, and molars with cingula restricted to the median buccal cleft. Although the presence of some of these conditions in Kenyapithecus was suggested earlier, the fragmentary and ill-preserved nature of previously known specimens led certain authorities to doubt their validity. Our assessment of mandibular and dental morphology indicates that K. africanus diverged after Proconsul and Griphopithecus but prior to the last common ancestor of Sivapithecus, extant great apes, and humans. The robustly constructed mandibular symphysis and anterior dentition suggest that incisal biting played as important a role as thick molar enamel in the dietary adaptations of K. africanus.

Animals↗
PubMed2002

The role of occlusal stress and gingival infection in the formation of exostoses on mandible and maxilla from Neolithic China.

Exostoses on the mandible and maxilla is a frequently observed bone growth of controversial aetiology. The aim of this study is to analyse environmental factors that may stimulate the formation of exostoses on different regions of the maxilla and mandible. Sixty-six well-preserved crania from Neolithic China were studied for the presence of buccal exostoses on the maxilla (BE) and lingual exostoses on the mandible (LME). Other oral health indicators, such as occlusal wear on molars, pathology of temporomandibular joint (TMJ), carious lesions, calculus accretion, periodontal disease, and antemortem tooth loss were recorded. Buccal maxillary exostosis was unusually common on the Neolithic skulls from China, which thus resemble the Sinantropus crania described by Weidenreich (1943). We report a significant Spearman correlation between BE and LME (rho = 0.54, P < 0.00001), suggesting a partially shared aetiology of these two types of exostoses. The highest correlations between either form of exostoses and any oral indicator of stress were found for pathology at TMJ (rho = 0.46, P < 0.0001 for both types of exostoses). Smaller but significant correlations were observed between LME and the age adjusted wear rate on lower molars, as well as between BE and indicators of oral/dental pathology, e.g. caries, calculus, periodontoses, and antemortem tooth loss. Both types of exostoses tended to increase in frequency with age, although a significant trend was observed only for BE. We conclude that formation of exostoses is a complex process that can be invoked by any agent causing damage and inflammation of gingival tissue. However, severe occlusal stress, which is often manifested in TMJ disorder, is the main environmental factor leading to exostosis development in genetically pre-disposed individuals.

Adult↗
PubMed1998

Morphology of the distal tip of the upper mandible of the ostrich (Struthio camelus) embryo during hatching.

1. The morphology of the distal part of the upper mandible in ostrich embryos was investigated using scanning electron microscopy just prior to and during hatching. 2. Although a keel-like structure on the tip of the upper mandible superficially resembles an egg tooth it appears to play no role during hatching. 3. The distal tip of the upper mandible is covered by an amorphous layer, the right side of which disappears during the hatching process. This layer acts to protect the beak during the rubbing process which creates a hole in the inner shell membrane during hatching.

Animals↗
PubMedDate not supplied

Skull and mandible formation in the cuckoo (Aves, Cuculidae): contributions to the nomenclature in avian osteology and systematics.

The study of the contributions of different bones to the formation of the skeleton in birds is necessary: (1) to establish homologies in comparative anatomy; (2) to delimit each bone structure correctly, mainly in relation to the skull and mandible where the bones are fused to each other in adults; and (3) to standardize nomenclature in avian osteology. In this paper at least one young specimen belonging to each sub-family of Cuculidae was examined in order to identify each bone in terms of boundaries and contributions to skull and mandible formation. These cuckoos specimens were also compared with adults and young of turacos and hoatzin. The results show little variation of skull and jaw among the young cuckoos studied compared with the variations among adult specimens. However, it provides new suggestions for the boundaries and nomenclature of certain osseous structures in the skull and mandible of birds, specifically fissura zona flexoria craniofacialis, prominetia frontoparietalis, crista temporalis transversa, processus squamosalis, fossa laterosphenoidalis, tuberculum laterosphenoidale and processus retroangularis. This study also provides more reliable homologies for use in cladistic analysis and above all it contributes to the phylogenetic position of Cuculidae within Neognathae, specifically the skull formation suggest that turacos and hoatzin are more similar to each other than either is to the cuckoos.

Age Factors↗
PubMed1995

Reactions of the mandible to experimentally induced asymmetrical growth of the maxilla in the rat.

The purpose of this investigation was to examine the interrelation in growth and morphogenesis between the maxilla and the mandible. Asymmetrical growth was induced in the maxilla of 10-day-old LE/T rats by means of unilateral artificial synostosis of the frontonasal and frontopremaxillary sutures. Untreated rats were used as controls. Biometric and microscopic observations were made at the ages of 30, 50, and 100 days. The arrest of sutural growth was followed by reduced sagittal growth of the maxilla, significantly more so on the treated side. Its anterior part became bent towards the treated side and rotated around the sagittal axis. In response to the primary alteration in maxillary shape, the mandible adapted by developing a secondary asymmetry in that it was shorter on the treated side than on the contralateral side throughout the experiment and shorter on the untreated side than in the untreated controls at 30 days. When the distances were adjusted for body weight, the mandibular length on the untreated side appeared to be virtually unaffected by the experimental procedure or even exceeded the control value at 50 days. The mandibular ramus was higher on the treated side than on the contralateral side at 30 days, and became bilaterally higher than in the untreated controls with increasing age. The results imply that the growth in length of the mandible follows that of the maxilla to some extent and are indicative of a restraining effect of the shortened maxilla on mandibular growth. The existence of a mechanism responsible for keeping the height of the ramus the same on both sides is suggested.

Aging↗
PubMed1999

The functional shift of the mandible in unilateral posterior crossbite and the adaptation of the temporomandibular joints: a pilot study.

Changes in the functional shift of the mandibular midline and the condyles were studied during treatment of unilateral posterior crossbite in six children, aged 7-11 years. An expansion plate with covered occlusal surfaces was used as a reflex-releasing stabilizing splint during an initial diagnostic phase (I) in order to determine the structural (i.e. non-guided) position of the mandible. The same plate was used for expansion and retention (phase II), followed by a post-retention phase (III) without the appliance. Before and after each phase, the functional shift was determined kinesiographically and on transcranial radiographs by concurrent recordings with and without the splint. Transverse mandibular position was also recorded on cephalometric radiographs. Prior to phase I, the mandibular midline deviated more than 2 mm and, in occlusion (ICP), the condyles showed normally centred positions in the sagittal plane. With the splint, the condyle on the crossbite side was displaced 2.4 mm (P < 0.05) forwards compared with the ICP, while the position of the condyle on the non-crossbite side was unaltered. After phase III, the deviation of the midline had been eliminated. Sagittal condylar positions in the ICP still did not deviate from the normal, and the splint position was now obtained by symmetrical forward movement of both condyles (1.3 and 1.4 mm). These findings suggest that the TMJs adapted to displacements of the mandible by condylar growth or surface modelling of the fossa. The rest position remained directly caudal to the ICP during treatment. Thus, the splint position, rather than the rest position should be used to determine the therapeutic position of the mandible.

Adaptation, Physiological↗
PubMedDate not supplied

Mandible shape analysis in a testicular feminization (Tfm) strain of mice.

The role of androgens on the sexual dimorphism of mandible shape was investigated in mice carrying the X-linked gene for testicular feminization (Tfm), which is known to determine a profound insensitivity to testosterone and is associated with a severe reduction in androgen receptor levels in Tfm/Y males. Mandible shape analysis in an inbred strain of mice segregating for the Ta (tabby) and Tfm mutations showed that the sexual dimorphism observed between +Ta/+Ta females and +Ta/Y males almost disappeared between Tfm+/+Ta females and Tfm+/Y males. In addition, a canonical discriminant analysis showed that these two closely related classes, Tfm+/+Ta and Tfm+/Y, are readily differentiated from both the +Ta/+Ta and +Ta/Y classes. These results suggest that androgens are involved in the mandible shape sexual dimorphism and play a role in mandibular development in both males and females.

Analysis of Variance↗
PubMed1981

Reconstruction of mandible with free osteocutaneous flap using deep circumflex iliac vessels as the stem.

One of the 2 patients introduced here had osteoradionecrosis, which has been difficult to reconstruct. The other had a massive adamantinoma that required replacement of the mandible from the midportion of the right ramus to the left angle with the iliac bone using the conventional method. The grafted iliac bone was severely absorbed, however. The mandible in both cases was successfully reconstructed with an osteocutaneous compound flap, using the deep circumflex iliac vessels as the stem. This method is considered a very good procedure for reconstruction of the mandible, which has been difficult by conventional procedures. Because the diameter of the stem is large, vascular anastomosis can be readily performed with an extremely high degree of safety. Pulsation of the stem can be palpated on follow-up even one year after surgery, and there are no signs of bone reabsorption.

Ameloblastoma↗
PubMed1994

Lengthening of the mandible by distraction osteogenesis: experimental work in rabbits.

The purpose of this experimental work was to lengthen the mandible in rabbits by means of distraction osteogenesis. The excellent results on the lengthening of the extremities with the Ilizarov technique and the unpredictable results in the mobilization of the facial bones by means of osteotomies and grafts are reasons for the application of the gradual distraction method in mandibular lengthening. Bone lengthening was first performed in 1905; but Ilizarov rekindled interest in 1951 when he induced bone neoformation in the extremities by the distraction technique using multiplanar wires and external circular fixators. We lengthened the mandible in 12 New Zealand adult rabbits using different mountings of the Ilizarov apparatus by means of two fixation techniques: transfixion and nontransfixion. In the transfixion group (6 rabbits), the two wires were passed through both mandibular rami. In this group, a 2-cm lengthening was obtained. In the nontransfixion group (6 rabbits), only one mandibular ramus was included with the transfixion wires. In this group, 1-cm lengthening was achieved. Unilateral lengthening was obtained with the nontransfixion technique and the lengthening of both rami with the transfixion technique. The results were evaluated by clinical periodic postoperative radiographs and histological studies of newly formed bone and surrounding soft tissues (masticatory muscles, arteries, and so on). The results demonstrated that lengthening of the mandible is obtained by means of a mature and normal new bone that is produced in the osteotomized area.

Animals↗
PubMed1999

The role of transforming growth factor-beta, insulin-like growth factor I, and basic fibroblast growth factor in distraction osteogenesis of the mandible.

Distraction osteogenesis is a viable method for regenerating large amounts of bone. In contrast to fracture healing, the mode of bone formation in distraction osteogenesis is primarily intramembranous ossification. The basic biology of the process is still not well understood. The growth factor cascade is likely to play an important role in distraction. This study examines the growth factor cascade in a lengthened ovine mandible model. Twenty-four animals were divided into four groups with varying rates of distraction (1, 2, 3, and 4 mm/day). A unilateral distractor at the angle of the mandible was used. The mandibles were lengthened to 24 mm and fixed for a period of 5 weeks, after which the animals were killed. The sections were probed for transforming growth factor-beta, basic fibroblast growth factor, and insulin-like growth factor I. The growth factors studied were present in all four groups. Transforming growth factor-beta, basic fibroblast growth factor, and insulin-like growth factor I were present in both the bony matrix of the sections and the cytoplasm of the cells, osteoblasts, and a small number of mesenchymal cells. The sections obtained from groups distracted at faster rates showed stronger presence of the growth factors examined by more intense staining. In fracture healing, the localization of transforming growth factor-beta in stage I of healing corresponded with the precise region of intramembranous ossification in stage II. Diffuse presence of transforming growth factor-beta throughout the lengthened region corresponded with the process of intramembranous ossification observed in distraction. In fracture healing, insulin-like growth factor I and basic fibroblast growth factor have been shown to promote proliferation and differentiation of osteoblasts from precursor cells. The intense presence of insulin-like growth factor I and basic fibroblast growth factor in the distracted region may account for osteoblast proliferation and formation from precursor mesenchymal cells. Mechanical strain has been shown to increase the expression of transforming growth factor-beta and insulin-like growth factor I. Distraction may serve as a source of mechanical strain, which may explain, in part, the expression of these growth factors, particularly in the faster groups.

Animals↗
PubMed2001

Fractures of mandible: is spontaneous healing possible? Why? When?

Closed and open reduction of fractures of the mandible constitutes an endless debate, and it is interesting that modern times have not brought a conclusion to this controversy. From 1995 to 1997 in the Plastic Surgery Department of Argerich Hospital in Buenos Aires, Argentina, 23 patients were evaluated with different fractures of the mandible in which neither closed nor open reduction was performed. Seventeen patients (74%) presented associated fractures in different areas of the mandible and 6 (26%) only had one fracture; 2 of them (9%) were edentulous. Three (13%) of the 23 patients had more than two fractures in different areas. Condylar fractures were the only lesion in 8 patients (35%), and they were associated with body fractures in another 6 patients (26%). Spontaneous healing of the fractures occurred in all 23 patients. No complications were found in any of them. All fractures presented the following characteristics: 1) Fractured fragments were aligned without displacement (or light displacement), 2) Occlusion was normal (or pretraumatic occlusion), 3) Facial symmetry was maintained, 4) Radiography demonstrated fractures without displacement, 5) Minor edema and hematoma were present in the area of the fracture, and 6) There was only pain during masticatory movements. The treatment was as follows: 1) Soft food and liquid diet (solid food was avoided 30 days after trauma), 2) Opening of the mouth was not permitted, 3) Oral antibacterial cleaning, and 4) Analgesic therapy. Spontaneous healing was produced by secondary bone repair mechanism as a "natural" process.

Analgesics↗
PubMed2006

Atypical courses of the mandibular canal: comparative examination of dry mandibles and x-rays.

Knowledge of the course of the mandibular canal and its anatomic variations is of great importance in oral surgery, especially in preprosthetic operations and the insertion of endosteal implants and during the planning of removable dentures prepared in cases involving extensively atrophied mandibles. We review the literature on duplicated mandibular canals, which is based exclusively on radiologic findings. Then, we compare this with an examination of dry mandibles and further radiologic studies. The incidence of duplicated mandibular canals observed in macroscopic examinations of mandibles was substantially higher than that revealed by radiographs. One case involving a novel variation, a triple mandibular canal, is reported.

Cadaver↗
PubMed2001

Distraction osteogenesis of the mandible for airway obstruction in children.

OBJECTIVES: Objectives of the study were to determine the effectiveness of distraction osteogenesis of the mandible to relieve airway obstruction in children with tongue-base airway obstruction and to describe the new surgical techniques developed for use in infants and young children. STUDY DESIGN: Prospective, nonrandomized study. METHODS: Analysis of 11 children with severe airway obstruction secondary to tongue-base obstruction was performed. Patients were between 2 weeks and 5.5 years of age. All patients underwent distraction osteogenesis of the mandible. RESULTS: Twelve distraction procedures in the 11 children in the study were accomplished; decannulation or extubation was successful in all children. CONCLUSION: Distraction osteogenesis of the mandible can be used to treat tongue-base airway obstruction in appropriately selected children.

Age Factors↗
PubMed2003

Management of vascular malformations of the mandible and maxilla.

OBJECTIVES/HYPOTHESIS: Vascular malformations involving the mandible and maxilla are uncommon, and no uniform treatment of these lesions has been defined. The purpose of the study was to evaluate the effectiveness of treating vascular malformations with a multidisciplinary approach and emphasis on endovascular therapy. STUDY DESIGN: Retrospective chart review of patients. METHODS: The treatment of 31 patients (13 male and 18 female patients) with mandibular and/or maxillary vascular malformations presenting between 1979 to 2001 was reviewed. RESULTS: Thirteen patients (42%) presented with mandibular vascular malformations, and an equal number of patients had maxillary vascular malformations. Five patients had involvement of both the mandible and maxilla. Twenty-six patients (84%) had adjacent soft tissue extension, whereas five patients had a vascular malformation isolated either to the mandible (four cases) or maxilla (one case). Twenty-six cases consisted of arterial vascular malformations, and five patients had venous and capillary types. Twenty-five patients (81%) were treated with embolization only, whereas six patients (19%) underwent combined embolization and surgical resection. "Cure" was defined as the complete eradication of disease or permanent resolution of symptoms with complete devascularization by embolization. The cure rates were 70% for mandibular malformations and 46% for maxillary lesions. None of the combined maxillary/mandibular lesions were cured, but all achieved improvement or stabilization of symptoms. The follow-up range was 1 to 22 years with an average follow-up of 6.7 years. CONCLUSION: The location and extent of vascular malformations dictate the treatment and resulting success. Endovascular therapy alone can effectively "cure" most mandibular and maxillary vascular malformations with limited soft tissue involvement. Extensive vascular malformations can be stabilized with control of symptoms, but eradication of the vascular malformation is unlikely even with combined surgery and embolization.

Adult↗