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There is a wide variation in the severity of median clefts of the lower lip and mandible. We report a severe case demonstrating clefts of the lower lip and mandible together with lack of supporting structures in the neck and upper sternum. Since a case with a cleft of the manubrium sterni is very rare, the literature is reviewed and discussed.
Arteriovenous malformation (AVM) of the mandible is a rare entity but one that can be potentially fatal as a result of massive hemorrhage. Traditional treatment involved extensive surgical resection of the mandible. With the advent of improved endovascular techniques, interventional radiology is now the best method to control active hemorrhage and ultimately cure these lesions. The authors describe three cases of successfully treated mandibular AVM by percutaneous and/or endovascular techniques.
OBJECTIVE: We sought to determine the suitable magnetic resonance imaging conditions for the short inversion time inversion recovery (STIR) sequence through the use of phantoms; to describe the signal characteristics of normal structures in the mandible; and to evaluate the usefulness of STIR images in enabling the identification of mandibular osteomyelitis on conventional T1- and T2-weighted spin-echo images. STUDY DESIGN: Suitable mandibular STIR imaging conditions were determined by varying inversion time and repetition time in each sequence. STIR magnetic resonance images of 162 healthy subjects and STIR and T1- and T2-weighted spin-echo images of 21 subjects with mandibular osteomyelitis were evaluated. RESULTS: In STIR imaging, the signal of oil was suppressed at an inversion time equaling 100 milliseconds and a repetition time equaling 1500 to 3000 milliseconds. In healthy subjects, the mandibular marrow was revealed to have high signal intensities (100%) and cortical bone had no signal intensities (100%) on STIR images. In surrounding soft tissue in these healthy subjects, the submandibular glands were shown to have high signal intensities (100%); the parotid glands had intermediate to high signal intensities (100%); the sublingual glands had high (88.9%) and intermediate to high (11.1%) signal intensities; lymph nodes had high signal intensities (100%); and the masseter muscles had intermediate signal intensities (100%) on STIR images. The lesions in bone marrow had low (75%) and low to intermediate (25%) signal intensities on T1-weighted images and high (54%), intermediate to high (29%), and intermediate (17%) signal intensities on T2-weighted images. On STIR images, the signal intensities resulted in high (75%), intermediate to high (21%), and intermediate (4%) signal intensities. CONCLUSIONS: STIR imaging is highly effective for the evaluation of bone marrow and surrounding soft tissue in terms of the detection of osteomyelitis in the mandible and the identification of inflammation spreading to soft tissue.
OBJECTIVES: This study compared the intraosseous biocompatibility of Vitremer, a new hydrophilic glass-ionomer cement, to that of Super EBA. STUDY DESIGN: Twenty-two New Zealand rabbits were anesthetized, the mandibular bone exposed, and two holes were drilled through the cortical plate. The materials were loaded into silicone carriers and inserted into the mandibles. Eleven rabbits were killed 4 weeks after implantation, 11 animals after 12 weeks. The mandibles were prepared with standard histologic procedures; the tissue reactions were graded from none to very severe. RESULTS: At 4 weeks Vitremer implants showed very slight to slight reactions, and the Super EBA implants showed slight reactions and one moderate reaction with no significant difference between the two materials. At 12 weeks, bone healing had occurred, despite the persistence of some fibrous tissue interposition. The reactions were classified as none to very slight for Vitremer and very slight to slight for EBA. Statistical analysis showed better results for Vitremer at 12 weeks. CONCLUSION: The intraosseous biocompatibility of Vitremer was similar at 4 weeks and superior at 12 weeks to that of Super EBA. Its other properties should be evaluated before considering its use in clinical practice.
Six patients with mucoepidermoid carcinoma in the mandible were studied with both panoramic radiography and computed tomography. Lesion shape and margin were evaluated on panoramic radiography, and bony expansion and cortical plate destruction were evaluated on computed tomography. In addition, a possible correlation among radiographic findings, histologic findings, and prognosis was investigated. Lesions found on panoramic radiography were classified into three types; each type pertained to two of the six patients. The lesion types were as follows: cystic, characterized by a large, cystic radiolucent area; rarefying, characterized by rarefying changes of the trabeculae; and infiltrative, characterized by a central ill-defined area of bony destruction. The results show that computed tomography is useful in the identification of tumor extent, bony expansion, and cortical plate destruction resulting from tumors. None of the patients whose lesions were of the cystic or rarefying type showed evidence of disease after surgery. In contrast, both of the patients whose lesions were of the infiltrative type died of their tumors. Histologic findings of the cystic and rarefying types showed tumors that were well-differentiated or moderately well-differentiated, whereas findings of the infiltrative type showed poorly differentiated tumors. Radiographic findings correlated with histologic findings and prognosis of mucoepidermoid carcinoma in the mandible in this limited series.
From a set of 31 three-dimensional computed tomography (CT) scans we model the temporal shape and size of the human mandible for analysis, simulation, and prediction purposes. Each anatomical structure is represented using 14851 semi-landmarks, and mapped into Procrustes tangent space. Exploratory subspace analyses are performed leading to linear models of mandible shape evolution in Procrustes space. The traditional variance analysis results in a one-dimensional growth model. However, working in a non-Euclidean metric results in a multimodal model with uncorrelated modes of biological variation related to independent component analysis. The applied non-Euclidean metric is governed by the correlation structure of the estimated noise in the data. The generative models are compared, and evaluated on the basis of a cross validation study. The new non-Euclidean analysis is completely data driven. It not only gives comparable results w.r.t. previous studies of the mean modeling error, but seems to better correlate to growth, and in addition provides the data analyst with alternative hypothesis of plausible shape evolution; hence aiding in the understanding of cranio-facial growth.
This study evaluated the deformations that contribute to Class III mandibular configuration, employing geometric morphometric analysis. Lateral cephalograms of male and female groups of 100 young adults and 70 children with Class III malocclusion were compared to those of counterparts with normal occlusion. The sample included an equal number of both genders. The cephalographs were traced, and 12 homologous landmarks were identified and digitized. Average mandibular geometries were generated by means of Procrustes analysis. Thin-plate spline analysis was then applied to mandibular configurations to determine local form differences in male and female groups of adults and children with normal occlusion and Class III mal-occlusion. The mandibular morphology was significantly different between these two groups of male and female adults, and children (p < 0.0001). This spline analysis revealed an anteroposterior elongation of the mandible along the condylion-gnathion axis, showing an extension in the regions of the mandibular condyle and ramus, and of the anteroinferior portion of the mandibular symphysis in Class III groups. More extension was evident in Class III adults. The deformations in subjects with Class III malocclusion may represent a developmental elongation of the mandible anteroposteriorly, which leads to the appearance of a prognathic mandibular profile.
Eighteen patients with bony defects of the mandible had the mandible reconstructed using conventional nonvascularized bone grafts from the iliac crest. After surgery they received radiotherapy for cancer in the oropharynx or oral cavity. This study was carried out over a 10-year period. All patients were followed-up both for their tumour growth and the results of their reconstruction. Four to 10 years after surgery 55.5 per cent were alive and well. Full dental rehabilitation was achieved in 33 percent and 12.5 percent were without dental rehabilitation.
We have compared the expression of osteonectin with that of osteocalcin and bone sialoprotein during bone formation in the rat mandible, using in situ hybridization and immunohistochemistry. Expression of osteonectin, osteocalcin and bone sialoprotein mRNAs were first observed in newly differentiated osteoblasts of the developing mandible at embryonic day 15 (E15) and subsequently increased with the number of osteoblasts through E20. Definitive osteonectin immunostaining was observed in newly differentiated osteoblasts, but not in the intercellular unmineralized matrix. Immunostaining for osteocalcin and bone sialoprotein was visible in osteoblasts and unmineralized matrix. Concomitant with the initiation of matrix mineralization at E16, mineralized bone matrix showed osteocalcin and bone sialoprotein immunostaining, but lacked osteonectin immunostaining. The same staining profile was observed during subsequent phases of bone formation at E17-20. However, sequential demineralization with ethanolic trimethylammonium EDTA and protease digestion of tissue sections demonstrated prominent osteonectin immunostaining of the mineralized bone matrix. Western blot analysis of osteonectin in extracts of fresh specimens at E18 and 20 revealed that an EDTA extract contains osteonectin having M, approximately 50 kDa. These results indicate that newly differentiated osteoblasts synthesize and secrete osteonectin, which is mainly incorporated into the mineralized bone matrix and becomes a specific component of developing manibula of foetal rats.
Type I collagen, fibronectin and tenascin C play an important role in regulating early osteoblast differentiation, but the temporal and spatial relationship of their localization during embryonic osteogenesis in vivo is notknown. The present study was designed to localize these three molecules in the dentary of mandibles and tibias in rat embryos using immunohistochemistry. Serial paraffin sections were cut and adjacent sections were processed for von Kossa staining or immunohistochemistry for type I collagen, fibronectin and tenascin C. In the dentary, tenascin C was localized within and around the mesenchymal cell condensation in embryos at 14 days in utero. The bone matrix at 15 days showed immunoreactivity for both type I collagen and fibronectin. The immunoreactivity of type I collagen was persistent, whereas that of fibronectin decreased with age of embryos. In tibias, tenascin C was localized in the perichondral mesenchymal tissue at 17 days. Immunoreactivity for type I collagen was persistent in the bone matrix, whereas the tibial bone showed little immunoreactivity for fibronectin at any embryonic age examined. The present study demonstrated characteristic localization of type I collagen, fibronectin and tenascin C during embryonic osteogenesis in the dentary of mandibles and tibias.
The aim of the present prospective clinical study was to analyze the feasibility of inserting Brånemark fixtures according to a one-stage procedure including transmucosal healing and to subsequently evaluate the predictability of osseointegration as well as the potential of such implants for stabilizing complete overdentures in the edentulous mandible. Five patients (2 women, 3 men), completely edentulous in the mandible and with a mean age of 60 years, volunteered for this study. Two fixtures of various length (10-20 mm) and 3.75 mm in diameter were inserted in the lower canine regions. A standard surgical procedure including a midcrestal incision was used. After the placement of the fixtures, healing abutments, which are normally used during second-stage surgery, were inserted instead of the usual cover screws. Three months after implant placement a clinical and radiographic examination was performed to confirm the presence or absence of osseointegration of the fixtures prior to exchanging the healing abutments with the spherical attachments. Finally, different clinical (Plaque Index, Bleeding Index, probing depth, Periotest mobility) and radiographic (bone loss, peri-implant radiolucency) parameters were recorded 9 months after loading of the fixtures by means of a complete mandibular overdenture, retained by two ball attachments in the canine regions. All fixtures were perfectly stable (mean Periotest values of -2) and presented favorable peri-mplant soft tissue conditions, and no patient was complaining about any particular symptom. As far as retention and stability of their implant supported overdenture was concerned, the participants without exception considered the therapeutic result as being perfectly adequate.(ABSTRACT TRUNCATED AT 250 WORDS)
In a 5-year prospective clinical study, 155 endosseous implants were installed in the mandible anterior to the mental foramina in 33 edentulous patients (13 males and 20 females). Usually 6 implants were installed for fixed prostheses (FP), 13 patients with 77 implants, and 4 implants for overdentures (OD) with a Dolder bar, 20 patients with 78 implants. At the time of abutment connection 1 implant in 2 patients was found to be loose and removed. However, in both these patients overdentures were successfully placed on the remaining 3 implants. Narrow-beam radiography was used for radiological evaluation. The mean (SD) total marginal bone loss in 5 years was 0.48 (0.38) mm (0.36 (0.22) mm in the FP group and 0.56 (0.45) mm in the OD group). Very few complications were reported during the 5 years, most of them being related to the superstructures. The overall cumulative implant survival rate was 98.7% (100% in the FP group and 97.4% in the OD group). The survival rate of the superstructures was 100%. The present study has demonstrated that Astra Tech implants offer reliable and predictable medium-term support for fixed prostheses and overdentures in the edentulous mandible.
The aim of this retrospective study was to evaluate the applicability of a horizontal osteotomy procedure for reconstruction of a narrow edentulous mandible in order to enable insertion of implants. In 7 edentulous patients a narrow inferior alveolar ridge was reconstructed with autogenous bone grafts harvested by a horizontal osteotomy procedure (mean width of the top of the alveolar crest before grafting 1.3 +/- 0.3 mm, after grafting 5.6 +/- 0.6 mm). Insertion of endosseous implants (10 Brånemark implants, 8 ITI Bonefit implants) was performed 3 months after the grafting procedure. Implant supported overdentures were fabricated 3 months after implantation. At regular time intervals a standardized clinical and a radiographic evaluation was performed. All grafted sites showed sufficient bone volume for insertion of the implants at the moment of implantation. At time of evaluation (mean 37 +/- 14.6 months, range 14-68 months) all implants and overdentures functioned well. None of the patients showed a disturbed sensitivity of the lip or chin region. It is concluded that reconstruction of a narrow edentulous mandible with autogenous bone grafts harvested by an intraoral horizontal osteotomy was shown to be a reliable preimplantology procedure with potential applicability in this group of patients.
The overall accuracy of a novel surgical computer-aided navigation system for placement of endosseous implants was evaluated. Five dry cadaver mandibles were scanned using high resolution computed tomography (HRCT). The position of four interforaminal dental implants was planned on the computer screen and transferred to the cadaver mandibles using VISIT, a surgical navigation software developed at the Vienna General Hospital. The specimens were HRCT-scanned again to compare the position of the implants with the preoperative plan on reformatted slices after matching of the pre- and postoperative data sets using the mutual information technique. The overall accuracy was 0.96 +/- 0.72 mm (range 0.0-3.5 mm). No perforation of the mandibular cortex or damage to the mandibular canal occurred. We conclude that computer-aided implant surgery can reach a level of accuracy where further clinical developments are feasible.
This research focuses on the effects of radiotherapy on the osseointegration of dental implants placed before or after radiotherapy in 11 male beagles. After the extraction of all mandibular premolars 1st and 2nd molars, three dogs were implanted without radiotherapy (Control group), four dogs were irradiated 4 weeks after implantation (IrA group) and four dogs were irradiated 8 weeks before implantation (IrB group). Eight implants were placed in each dog, in an alternating pattern: four nonsubmerged ITI Bonefit titanium plasma spray-coated and four submerged Steri-Oss hydroxyapatite-coated. The irradiated dogs received 4.3 Gy daily for 10 days. Two different fluorescent markers were administered at the time of implantation and of irradiation. The dogs were sacrificed 6 months after implantation, i.e. 5 months after radiotherapy for the IrA group and 8 months for the IrB group. Each mandible was submitted to histological and microradiographic analysis. Bone formation occurred around 85 of the 88 implants and consisted mostly of the successive deposit of woven and lamellar bone. Both irradiated groups showed obvious bone remodeling in alveolar bone as well as in the basilar part of the mandible. Nevertheless, in the IrA group, the resorption phenomena predominated over osteogenesis. The balance between these two opposite processes seemed to be restored 8 months after the end of radiotherapy (IrB group). In spite of focal lesions of radiation-specific bone destruction emphasized in some irradiated dogs, we conclude from our results that osseointegration of dental implants is possible in irradiated bone tissue.
The aim of the study was to compare the bone mineral apposition rate (BMAR) of immediately loaded implants with an unloaded control during the early healing phase in the partially edentulous mandible. In seven mini pigs, three premolars and the first molar were removed in the left mandible. Three months later, five implants were installed. Four implants received a fixed provisional restoration and were loaded immediately. The most anterior implant was used as unloaded control. Polychromatic fluorescence labelling was performed to assess the BMAR. After 4 months, the implants were retrieved together with the adjacent bone. Histological specimens were prepared and subjected to a fluorescence microscopic and histomorphometric analysis. Two provisional restorations were found partially lost at the end of the observation period. One implant that had lost the splinting fixation showed soft connective tissue healing. The BMAR did not differ statistically significantly between loaded and unloaded implants and within the single groups during the observation period (BMARloaded days 14-42=1.8+/-0.2 microm/d, BMARloaded days 42-70=1.8+/-0.1 microm/d, BMARloaded days 70-98=1.6+/-0.1 microm/d, pBMARloaded days 14-42/42-70/70-98 =0.156, BMARunloaded days 14-42=1.7+/-0.1 microm/d, BMARunloaded days 42-70=1.8+/-0.2 microm/d, BMARunloaded days 70-98=1.6+/-0.4 microm/d, pBMARunloaded days 14-42/42-70/70-98=0.368, pBMARloaded/unloaded days 14-42=0.073, pBMARloaded/unloaded days 42-70=0.098, pBMARloaded/unloaded days 70-98=0.262). Four months after implant placement, the bone-to-implant contact was 77.8+/-17.3% for the loaded and 78.0+/-5.8% for the unloaded implants (P=0.753). Immediate loading does not affect the bone mineral apposition rate when compared with unloaded implants. Rigid splinting seems to be the crucial factor for implant success. Uncontrolled masticatory forces can cause failure after partial loss of the provisional restoration.
The objective of the present report was to study the effect of implant treatment on subjective parameters in edentulous patients with an extremely resorbed mandible. Three different treatment modalities to support an overdenture were compared: transmandibular implant according to Bosker, augmentation of the mandible followed by four endosseous implants, and the insertion of four short endosseous implants. Sixty patients [50 women and 10 men, mean (+/- SD) age 59 (+/- 11) years] met the inclusion criteria and were assigned in one of the three treatment groups. Before treatment and 12 months after placement of the new overdentures, denture satisfaction, psychosocial aspects and experiences during the surgical phase were assessed with a battery of questionnaires. After 1 year, 58 patients were available for evaluation: one patient had died, and one patient had moved out of the region. There was a significant improvement of patient satisfaction and psychosocial functioning in all three treatment groups. At the 1-year evaluation, differences amongst the three groups were not significant. However, in terms of discomfort and pain during the surgical phase as well as the length of this phase (at least 6 months), the augmentation using an autologous bone graft from the iliac crest followed by inserting four endosseous implants 3 months later appeared the least favorite option of the three modalities studied.
Both arteriovenous malformations (AVMs) and solitary bone cysts of the mandible are uncommon lesions. The latter can be considered fairly innocuous but AVMs require careful management. The following is a description of a case where an arteriovenous malformation of the mandible presented with mental nerve paraesthesia. However, radiographically the features appeared to be consistent with a solitary bone cyst. It is important for clinicians in both a primary and secondary care setting to be aware that this type of lesion can have life threatening complications.