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At least 127 records · Page 7Linked to original sources
PubMed1997

Functional and morphologic alterations after anterior or inferior repositioning of the maxilla.

PURPOSE: The purpose of this investigation was 1) to compare functional and morphologic measurements between controls and patients scheduled for anterior or inferior repositioning of the maxilla, and 2) to examine how these patients' oral function adapted after surgery. PATIENTS AND METHODS: Nine male patients undergoing anterior and/or inferior repositioning of the maxilla were compared with 26 male controls preoperatively and up to 3 years after surgery. Measures of skeletal morphology, mandibular range of motion, maximum voluntary bite force, and levels of electromyographic (EMG) activity in the anterior and posterior temporalis and masseter muscles during isometric bites were made on all subjects over time. One-way ANOVA was used to compare the controls, the patients before surgery, and the patients after surgery. RESULTS: Before surgery, most of the patients had morphologic characteristics of mandibular prognathism and maxillary retrognathism. Surgery made the patients' skeletal morphology similar to controls except for mandibular length, upper facial height, and palatal plane angle, which were significantly greater than those of controls. There were no significant differences in jaw muscle mechanical advantage between controls and patients either before or after surgery. Hypomobility of the jaw was apparent at 6 weeks and 6 months after surgery, but returned to normal values within 1 to 2 years. Before surgery, the patients had maximum voluntary bite forces significantly less than those of controls. Bite forces in patients steadily increased after surgery, approaching significantly higher values than those of controls. Before surgery, patients' muscle activity levels per unit of bite force were not significantly different from those of controls. Most of the patients' muscle activity levels per unit of bite forces at all bite positions showed no significant change after surgery. CONCLUSIONS: The results of this study suggest that anterior or inferior repositioning of maxilla produces some significant functional benefits in patients.

Adult↗
PubMed1999

Implant treatment without bone grafting in severely resorbed edentulous maxillae.

PURPOSE: This article describes the surgical technique for implant treatment in severely resorbed edentulous maxillae without any alveolar reconstruction before or combined with implant placement. PATIENTS AND MATERIAL: Fifteen patients with severely resorbed edentulous maxillae were treated with osseointegrated implants and fixed dental prostheses. All patients were initially considered to be treated with bone grafting because of a lack of sufficient bone volume for conventional treatment. Preoperative radiographic examinations showed that the height of the alveolar crest was on average 7.4 mm at the 4-mm-width level (Classes V to VI). RESULTS: By fenestration of the maxillary sinus and uncovering the nasal floor, the maxillary bone could be visualized and used maximally for installation of implants. By angulation of the implants and permitting two to five uncovered fixture threads on the palatal aspect, implants of optimal length could be installed. Eighty-six implants were placed (four to six implants in every patient). One implant was lost during the observation time (range, 36 to 54 months; mean, 45 months). All patients had stable fixed prostheses at the end of the observation time. CONCLUSION: This cost-effective surgical technique may be considered as an alternative to more resource-demanding techniques such as bone grafting in patients with severely resorbed edentulous maxillae. However, further prospective comparative studies are necessary for full evaluation.

Adult↗
PubMed1978

The behaviour of the maxilla in vertical movements after Le Fort I osteotomy.

In 15 cases of ordinary Le Fort I osteotomy with simultaneous vertical displacement, the behaviour of the maxilla in respect to vertical movement was examined. It was observed that out of 12 maxilla which had been tilted downwards, 10 moved upwards again. One maxilla remained stable and another one moved further downwards. Of 3 cases with upward movement, two remained stable whereas one moved further upwards. Therefore, the authors conclude that the downward displacement especially is unstable and that one has either to overcorrect or search for possibilities of stabilization other than wiring suspension. Since these movements occur during postoperative intermaxillary fixation, no occlusal changes are observed.

Adolescent↗
PubMed1997

Iliac apophyseal cartilage augmentation of the deficient piriform rim and maxilla in alveolar cleft grafting.

This article presents a new approach to cleft lip and cleft palate repair, where the retained bulk of alveolar cleft grafts is augmented by simultaneous cartilage augmentation of the deficient maxilla. Nine patients who provided 10 cleft sites underwent secondary bone grafting of the clefted alveolus by this technique. This study evaluates the following: (1) the postoperative esthetic results, (2) the quantity of bone in the grafted area, and (3) the provision of bone support for unerupted teeth, for teeth adjacent to the cleft, and for orthodontic tooth movement when the secondary bone grafting of the cleft is integrated with the onlay augmentation of the deficient maxilla. Photographic and radiographic investigations were undertaken. The photographic evaluation showed that all patients exhibited improved facial esthetics in the area of the cleft, particularly in the paranasal area of the maxilla; improved alar base support, symmetry of the columella, and less deviation of the tip of the nose were seen. The radiographic evaluation indicated the following: (1) the average percentage of the alveolar bone height of the grafted area was equal to 76% of the normal side; (2) nine canines erupted or were erupting through the grafted area; there were no adequate records to evaluate the fate of the remaining canine; (3) no teeth involved in the cleft area were ankylosed, because of inadequate records, so evaluators could not determine the status of one tooth; (4) all patients had adequate quantity of bone for orthodontic tooth movement through the grafted area; and (5) the periodontal support of the teeth involved in the cleft was adequate.

Alveolar Process↗
PubMed1993

Bilateral transverse facial clefts and accessory maxillae--variant or separate entity?

We report an extremely rare case of bilateral transverse facial clefts and accessory maxillae with severe mandibular hypoplasia in a 7-year-old Chinese boy. The transverse facial clefts had been repaired in infancy. The accessory maxillae were excised via a combined temporal and oral approach. Functional orthodontic appliance therapy was not feasible due to restricted protrusive movements of the mandible. Bimaxillary osteotomies were performed one year later due to failure mandibular catch-up growth to occur. The pathogenesis of the accessory maxillae in the presence of lateral facial clefting is postulated to be compensatory mesenchymal growth from the temporal region, and a case is made for this condition to be considered as a possible syndrome rather than a variant of the transverse facial cleft.

Child↗
PubMed1989

A new method of inserting endosseous implants in totally atrophic maxillae.

A new method is described (Sailer, 1988) whereby endosseous implants are inserted in the totally atrophic maxilla, the intermaxillary relationship and vertical dimension corrected and a vestibuloplasty performed during one surgical procedure. The method can also be used to treat minor degrees of maxillary alveolar atrophy. The procedure enables 20 mm-long Titanium screws to be used in totally atrophic maxillae. The following surgical procedures are carried out during one operation: A Le Fort I osteotomy, removal of the mucous membrane of the sinus floor, obturation of the denuded maxillary sinus floor by autologous bone grafts from the iliac crest, simultaneous insertion of Titanium screws, fixation of the down-fractured maxilla by miniplates, and a modified submucous vestibuloplasty. Intermaxillary relationship and vertical dimension can be normalized, and the aesthetic results are excellent. To date 35 implants of which none has been lost, have been placed in 5 patients.

Alveolar Ridge Augmentation↗
PubMed1999

Characteristic features of trabecular bone in edentulous maxillae.

Following tooth loss, the maxillary alveolar ridge is affected by extensive resorption and its cancellous bone substance undergoes intense remodeling processes. This is particularly important for endosseous implant surgery as the primary stability and thus the prognosis of endosseous implants depends on the cancellous bone density and structure of the alveolar ridge. To analyze the structure of alveolar trabecular bone, 156 sections were obtained from 52 edentulous maxillae (29 female, 23 male; mean age: 72.5 years) from the lateral incisor, first premolar, and first molar regions. The structural histomorphometric analysis was performed on cancellous bone of the section surfaces using semiautomatic image analysis. The following parameters were measured: trabecular bone volume, trabecular number, trabecular thickness, trabecular plate separation and trabecular interconnection. All examined parameters showed an extreme range of variation. A difference of more than 45% between the highest (= 51.93%) and the lowest (= 6.73%) trabecular bone volumes was found. Furthermore, the measurements showed that trabecular bone volume, thickness and number were distinctly lower in the molar region than in the incisal and premolar regions. Significant sex-specific differences were found in all investigated regions, female maxillae showing a smaller amount and a lower connectivity of cancellous bone than male maxillae.

Adult↗
PubMed2000

An assessment of the accuracy of ridge-mapping in planning implant therapy for the anterior maxilla.

The use of ridge-mapping to assess bone levels available for implant placement in the anterior maxilla avoids some of the problems associated with CT scanning. The aim of this study was to assess the accuracy of ridge-mapping callipers in determining body ridge widths in the anterior maxilla prior to dental implant surgery. A modified surgical stent was designed to locate the beaks of ridge-mapping callipers at the same points on the jaw before and after mucoperiosteal flap reflection. Eleven subjects were included in the study. Measurements (n = 100) were made at 25 implant sites, 50 "pre-operative" and 50 "intra-operative" at 3 mm and 6 mm distances from the crest of the ridge. There were statistically significant (P < 0.0001) differences between pre- and intra-operative measurements. Based on pre-operative measurements, clinical judgements were made as to whether supplementary procedures such as guided bone regeneration would be required. Unanticipated supplementary procedures were required at 10 fixture sites. The findings indicate that ridge-mapping alone is insufficient to accurately predict bone available for implantation in the anterior maxilla. It is suggested that ridge-mapping may provide reliable information about bone levels when the labial aspect of the anterior ridge is not markedly concave.

Alveolar Process↗
PubMed2002

A prospective study evaluating a protocol for 6 weeks' loading of SLA implants in the posterior maxilla: one year results.

Experimental and clinical studies have shown that modification of implant surfaces can result in increased bone-to-implant contact at earlier times thus reducing the healing period between surgery and prosthesis. Sandblasted and acid-etched (SLA) implants are in this category and have successfully undergone early loading in patients with good bone quality and quantity. Nevertheless, premature loading of SLA implants was not routinely possible in predominantly trabecular bone, such as the posterior maxilla, as it is often characterized by a deficiency in initial bone to implant contact. The purpose of this prospective clinical investigation is to evaluate the efficacy of a modified surgical protocol followed by loading SLA implants at 6 weeks in the posterior maxilla. Drilling was limited to the minimum, and most of the site preparation was produced with osteotomes. Screw tapping was never performed and primary stability was always achieved. Abutment connection was carried out at 15 Ncm 43 (+/- 1) days after surgery and provisional restoration was fabricated. Further abutment tightening at 35 Ncm was performed after an additional 6 weeks. Of the 36 SLA implants placed in 19 patients, one was lost before final restoration. Clinical and radiographic measures were taken at baseline and 1 year postoperatively. The preliminary results suggest that, by means of the surgical and restorative technique presented, SLA implants are suitable for loading at 6 weeks in the posterior maxilla. More years of observation will verify whether osseointegration can be equally maintained over a long period.

Acid Etching, Dental↗
PubMed2006

Treatment planning of the edentulous maxilla.

The predictability of successful osseointegrated implant rehabilitation of the edentulous jaw as described by Branemark et al., introduced a new era of management for the edentulous predicament. Implant rehabilitation of the edentulous maxilla remains one of the most complex restorative challenges because of the number of variables that affect both the aesthetic and functional aspect of the prosthesis. Among the prosthesis designs used to treat the edentulous maxilla are fixed or removable implant-supported restorations. Since the aesthetic requirements and preoperative situation of each patient varies, considerable time must be spent on accurate diagnosis to ensure patient desires are satisfied and predictable outcomes are achieved. The purpose of this article is to compare the treatment options and prosthesis designs for the edentulous maxilla. Emphasis will be placed on diagnosis and treatment planning. Criteria will be given to guide the practitioner in deciding whether a fixed or removable restoration should be placed. This objective will be accomplished through the review of cases with regard to varying design considerations and factors that influence the decision-making process.

Aged↗
PubMed1976

Cervical retraction of the maxillae in the Macaca mulatta monkey using heavy orthopedic force.

Heavy, interupted orthopedic forces were employed for the cervical retraction of the maxillae in two Macaca mulatta monkeys. The nature, location and magnitude of resultant movements and remodelling were studied with the help of plaster casts, amalgam implants, lateral cephalometric tracings, and of gross and microscopic study of the skulls themselves. The principal effect of the retractive force was a marked downward and backward rotational movement of the maxillae which carried the maxillary teeth into posterior crossbite and a severe Class III molar relationship. Posterior movement of the tuberosity entirely closed the pterygomaxillary fissure so that the tuberosity impinged upon the pterygoid plates. Like the maxillae, the mandible, premaxilla, and nasal boned also moved downward and backward. These changes increased the vertical dimension of the face and diminished it horizontally leaving a flattened facial profile from the nasal opening to the maxillary incisors. Movement of facial elements posteriorly against an unhielding anterior cranial base imposed a number of other compensatory changes. These included generalized resorption at the craniofacial sutures and sliding of the sutures upon each other. They also involved mutual resorption of the maxillary tuberosity and of the pterygoid plates together with remodelling and lateral extension of the malar bones. Tolerance of the animals and of the localized tissues for these intensive forces suggests a significant role for this form of therapy. Clinical application, however, should be tempered by judicious concern for the vital structures of the pterygomaxillary fissure which could be impinged or strangulated by excessive retrusive force.

Activator Appliances↗
PubMed2004

Statistical evaluation of possible factors affecting the sagittal position of the first permanent molar in the maxilla.

A cephalometric analysis was designed to evaluate several factors that may affect the sagittal position of the maxillary first permanent molar. A total of 184 Class II and Class I malocclusion patients were randomly selected before orthodontic treatment. The mandibular and palatal planes were related to Frankfort Horizontal and used to create the interjaw or B angle. Age and cephalometric landmarks (Ba, N, point A, pterygomaxillary fissure, and maxillary molars) were projected at right angles to the Frankfort Horizontal for effective length. Actual maxillary length and actual molar location were determined by projecting landmarks at right angles to the palatal plane. Correlation coefficients and P values were used to evaluate the data with a minimal significance value of .05 to determine a 95% confidence level. A statistically significant linear and proportional positive correlation (P < .0001) existed between molar location, age, and maxillary size. There was a strong negative correlation (P < .0001), both linearly and as a proportion of the actual length of the maxilla, between the actual position of the maxillary molar and the interjaw and mandibular plane angles. A significant correlation also existed between the molar position and palatal plane angles. The results show that increased interjaw, mandibular, and palatal plane angles are accompanied by a more posterior position of the maxillary first molar in the maxilla, whereas the molar occupied a continuing more forward position in the maxilla with increasing age, cranial base length, and maxillary size.

Age Factors↗
PubMed2002

Relationship between formation/eruption of maxillary teeth and skeletal pattern of maxilla.

Previous reports have indicated that formation and eruption of the maxillary teeth, especially the molars, are delayed in skeletal Class III patients compared with Class I and Class II patients. However, the relationship between the formation/eruption of maxillary teeth and the skeletal pattern of the maxilla is not yet clear. To examine this relationship, we studied 81 skeletal Class III Japanese patients (mean age, 8.8 years). The sample was divided into 2 groups: a maxillary retrusion (MR) group, characterized by a small SNA angle and a short palatal length, and a control group in which those values were in the normal range for patients of Japanese descent. There was no significant difference in the rate of formation for the maxillary and mandibular teeth between the 2 groups. The eruption of the maxillary second molars was delayed in the MR group compared with the control group. There were no significant differences between the 2 groups for any other teeth. A multiple-regression analysis was carried out to examine whether the skeletal pattern of the maxilla is a useful indicator for predicting the eruption of the maxillary teeth. The results showed that palatal length and chronologic age were significant independent (explanatory) variables for predicting eruption of the maxillary second molars. These findings indicated that the skeletal pattern of the maxilla is a useful indicator for predicting the timing of maxillary molar eruption when considering treatment of skeletal Class III malocclusions.

Age Factors↗
PubMed2004

Zygoma fixture in the management of advanced atrophy of the maxilla: technique and long-term results.

Despite refinements in surgical technique, including bone grafting and sophisticated prosthetic reconstructions, there are limitations to what can be achieved with bone-anchored fixed prostheses in patients with advanced atrophy of the maxillae. A new approach was suggested by a long-term study on onlay bone grafting and simultaneous placement of a fixture based on a new design: the zygoma fixture, and the aim of this study was to assess its potential. Twenty-eight consecutive patients with severely resorbed edentulous maxillae were included, 13 of whom had previously had multiple fixture surgery in the jawbone that had failed. A total of 52 zygoma fixtures and 106 conventional fixtures were installed. Bone grafting was deemed necessary in 17 patients. All patients have been followed for at least five years, and nine for up to 10 years. All patients were followed up with clinical and radiographic examinations, and in some cases rhinoscopy and sinoscopy as well. Three zygoma fixtures failed; two at the time of connection of the abutment and the third after six years. Of the conventional fixtures placed at the time of the zygoma fixture, 29 (27%) were lost. The overall prosthetic rehabilitation rate was 96% after at least five years of function. There were no signs of inflammatory reaction in the surrounding antral mucosa. Four patients with recurrent sinusitis recovered after inferior meatal antrostomy. To conclude, the zygoma fixture seems to be a valuable addition to our repertoire in the management of the compromised maxilla.

Bone Transplantation↗
PubMed1990

Growth displacement of the maxilla in girls studied by the implant method.

The sutural growth displacement of the maxilla between the ages of 8 and 21 years was studied on 14 series of lateral cephalometric films of girls from the Björk implant sample (Björk 1968). The assessment of growth changes was based on the method of superimposition described by Björk and Skieller (1983) supplemented by a new computerized debugging procedure. A new method for angular measurement of the forward displacement of the maxilla and the mandible is described here. The average forward displacement of the maxilla in relation to the anterior cranial base was 6 degrees from 8.5 to 17.5 years. The average path of displacement was inclined about 45 degrees in relation to the nasion-sella line from 8.5 to 14.5 years, and then changes to almost horizontal. The mean distance between anterior and posterior implant points showed a continuous shortening, totalling 0.6 mm for the period 8.5 to 15.5 years, due to maxillary rotation in the transverse plane. The timing of growth differed between the horizontal and vertical components of the maxillary growth translation. Horizontal displacement peaked at 11 and terminated at 18 years, whereas vertical displacement peaked at 12 and terminated at 15 years of age.

Adolescent↗
PubMed1997

Effects of experimental unilateral condylectomy followed by altered mandibular function on the maxilla and zygoma.

The effect of protruded mandibular function on the maxilla and zygoma was studied in young unilaterally condylectomized growing rats. Forty-eight-4-week-old rats were divided into two experimental and two control groups as follows: group A, 12 animals unilaterally condylectomized on the right side; the mandible was allowed to function normally; group B, 12 animals unilaterally condylectomized on the right side; the mandible was protracted forwards immediately by means of an appliance; group C, 12 animals sham-operated on the right side; no condylectomy or mandibular protraction; and group d, 12 control animals not subjected to any operation or mandibular protraction. The mandibular protraction was achieved by an appliance consisting of an acrylic collar brace fitted to the animal's neck and supporting rubber bands pulling on an intraoral part cemented on the animal's lower incisors. Twenty-five grams of pulling force and protrusion to a clinically and radiographically testes anterior crossbite was exercised for 12 hours per day. The experimental period was 30 days. Lateral and dorsoventral radiographs were taken on days 1 and 30 following condylectomies and mandibular protraction. Cephalometric analysis was performed for each animal with measurements evaluating the maxilla and zygoma. Statistical analysis and comparison of the findings in the four groups of animals can be summarized as follows: (i) condylectomy and altered mandibular function may produce remote skeletal reactions in other parts of the cranial complex; and (ii) the ipsilateral maxilla is affected by condylectomy of the mandible, but altered mandibular function by protraction compensates for the results of condylectomy.

Animals↗
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↗
PubMed2000

Fixed implant rehabilitation of the edentulous maxilla: clinical guidelines and case reports. Part II.

Fixed prosthetic implant reconstruction of the edentulous maxilla demands skill and state-of-the-art techniques of both the surgeon and the restorative dentist. As discussed in Part I (Implant Dent. 1999;8: 186-193), accurate diagnosis and treatment planning are essential to successful, predictable clinical results. How and where implants are placed have a lasting impact on the quality and prognosis of the final restoration. A series of clinical guidelines and considerations is reviewed with illustrative clinical treatment protocols of edentulous maxillae of unfavorable anatomy including attendant prosthetic difficulties. This article addresses the fixed implant rehabilitation of edentulous maxillas with inadequate posterior bone and favorable arch position, inadequate posterior bone and unfavorable arch position, and inadequate anterior and posterior bone and unfavorable arch position.

Adult↗