Maxillary Residual Ridge Research Articles

Patient Satisfaction with Complete Denture Constructed Using Modified Windows Impression Technique with Custom Dual Tray for hypermobile Maxillary Residual Ridge

Patient Satisfaction with Complete Denture Constructed Using Modified Windows Impression Technique with Custom Dual Tray for hypermobile Maxillary Residual Ridge

Analysis of Residual Ridge Morphology in a Group of Edentulous Patients Seeking NHS Dental Implant Provision-A Retrospective Observational Lateral Cephalometric Study.

A convenience sample of 154 edentulous patients referred for implant provision at a Regional National Health Service Dental Hospital in the North West of England were identified. The cephalometric radiographs that were taken as part of the patient baseline investigation were assessed. Digital tracing was used to measure the anterior maxillary and mandibular bone height and ridge angle with respect to the maxillary and mandibular planes. The mean height of the bone in the maxilla was found to be 14 mm, and the mean ridge angle for the anterior maxillary residual ridge is 104°. The mean height of bone in the mandible was 18 mm, while the mean ridge angle for the anterior mandibular residual ridge was 77°. Using the Cawood and Howell classification demonstrated that class VI mandibles were the most common. The cross-sectional shape of the mandible varied, with the triangular shape most common. Although there was adequate bone stock for implant placement in these cases, the mandibular residual ridge resorption presents a lingual inclination to the residual bone. The limited residual ridge position and inclination would dictate that conventional implant placement could be challenging.

Stress distribution in tooth supported removable partial denture fabricated using two different materials: A 3-dimensional finite element analysis

A suitable material and design plays an important role in the fabrication of a removable prosthesis. The distribution of forces plays a significant role in preservation of the remaining structures especially the abutment teeth. In this study 2 models were prepared using, computed tomography (CT Scan) and 3-Dimensional construction software; of Kennedy’s Class 3 partially edentulous situation. The models were classified based on the material used in fabrication of the prosthesis as; Model 1- Cobalt Chromium denture; Model 2-Thermoplastic Nylon dentures. The meshing of the models was done using hyper mesh 13 and, the contact and constraint conditions were defined for the analysis model. The material properties were incorporated and the stress analysis was done by applying an unidirectional force of 40 N per tooth on three posterior teeth. The analysis was done using ANSYS version15 and the results were analyzed. Model 1 (cobalt chromium) showed a maximum displacement of 0.00718 mm and maximum stress of 19.87 MPa, Model 2 (Thermoplastic nylon) showed the maximum displacement of 0.0094 mm and maximum stress was 29.97 MPa. Within the limitations of this study the stress evaluation on different prosthetic materials revealed that the areas of maximum stress were seen on the palatal slopes of the maxillary residual ridge and on the anterior abutment tooth (canine) in both models. However, the Cobalt-Chromium model showed significantly lesser stress as compared to the Thermoplastic nylon model.

Screening and Allotting Completely Edentulous Patients using Prosthodontic Diagnostic Index in a Dental School, Jeddah, Saudi Arabia

Introduction: To formulate an ideal treatment plan for edentulous patients, data collected from various diagnostic aids need to be structured and classified according to their treatment needs. The lack of structured diagnostic findings for edentulous patients has always been a barrier to effective care for patients. To address these issues, the American College of Prosthodontists (ACP) established the Prosthodontic Diagnostic Index (PDI) based on specific criteria. Aim: To screen and allot completely edentulous patients to students using PDI in a dental school, in Jeddah, Saudi Arabia. Materials and Methods: This cross-sectional study was conducted on 122 completely edentulous patients who visited the outpatient clinic of a dental school in Jeddah, Saudi Arabia. The edentulous patients based on PDI were classified into four classes (Class I–IV) according to the diagnostic findings based on the complexities. The parameters studied were: mandibular bone height measured on a panoramic radiograph, residual ridge morphology of the maxillary arch, muscle attachments in the mandibular arch, and maxillomandibular relationship. Statistical analyses were performed using counts and percentages. Results: In the overall classification of PDI maximum 52 (42.6%) patients were classified as Class IV. Among the different criteria of PDI, 48 (39.4%) patients exhibited Class III mandibular bone height of 11-15 mm, whereas 40 (32.8%) patients exhibited Class IV mandibular bone height of 10 mm or less. In the maxillary residual ridge morphology, 62 patients (50.8%) were classified as Class I. A large number of patients 84 (70%) had Type A mandibular muscle attachment criteria and were classified as Class I or II. In the maxillomandibular relationship, the maximum number of patients 74 (60.7%) was of Class I. Conclusion: The majority of patients in the study were categorised as Class IV (severely compromised). Edentulous patients must be classified according to PDI during the initial screening phase so that less complex cases (Class I and II) can be allotted to undergraduate students and more complex cases (Class IV) can be handled by prosthodontists or can be referred to specialist centers so that costly and time-consuming remake of complete dentures can be avoided.

A Review on Occlusal Plane Analysis in Edentulous Patients

Aim: The Purpose of the present review was to determine the occlusal plane in edentulous patients.Objective : Occlusal plane orientation is an important factor in the construction of a complete denture.Occlusal plane could be oriented using landmarks in the maxillary arch as well as the mandibular arch .Many methods have been used to establish the occlusal plane in complete dentures , but no method seemsto be fully acceptable. So it is always challenging for the prosthodontist to restore the existing occlusalcondition with a suitable prosthesis.Materials and Methods : : An electronic search engine without time/ language restrictions was taken fromGoogle Scholar .Conclusion: This article reviews different techniques to determine and correct occlusal plane. HIP wasparallel to the occlusal plane , Ala-tragal line passing through lower part of the ala of the nose to inferiorposition of the tragus was relatively parallel to maxillary residual ridge. Therefore, this may be a viablereference in complete denture prosthodontics.

Objective computerised assessment of residual ridge resorption in the human maxilla and maxillary sinus pneumatisation.

Atrophic resorption of the maxillary alveolar ridge is a complication that makes implantological rehabilitation critical. Our aim was to develop a novel computer aided procedure for the accurate quantitative assessment of maxillary residual ridge resorption including pneumatisation of the maxillary sinus that goes beyond previously described approaches and to apply it to a large dataset. To develop and refine the method, we performed a retrospective analysis using computed tomography data from 405 patients to generate segmented, three-dimensional models of zygomaticomaxillary bones and maxillary sinuses. Using anatomical landmarks and orientation lines or planes, all models were aligned automatically to subsequently generate cross-sectional images (n = 2835), enabling the classification of atrophy as well as the quantification of volumes and caudal extensions of the maxillary sinuses. We developed and implemented an accurate and reproducible workflow for the semi-automated analysis of volumetric maxillary images. Comprehensive statistical analysis of the large quantitative dataset revealed various correlations of maxillary process heights and sinus volumes with atrophy class, age and region and identified conjectural trends over the patient group. The method was used successfully to process a large dataset to classify atrophy, to measure alveolar height parameters, and to quantify maxillary sinus volume, bottom volume and pneumatisation. Apart from the anthropometric value of the generated dataset, the method could be applied to provide additional and more accurate data to assess the necessity of bone augmentation in the context of three-dimensional planning before implantation.

Clinical Evaluation of Residual Ridge Morphology of Maxillary Arch in Relation to Ageing and Length of Edentulism

Background: Ridge morphology is one of the important recognized factors affecting denture retention, stability, support and masticatory function in edentulous patients. The form of ridge affects the planning as well as determines the prognosis of treatment. The objective of this study was to assess maxillary residual ridge morphology according to American College of Prosthodontists (ACP) classification system and to find association between type of ridge morphology of maxillary arch with age and duration of edentulism. Methods: The study was conducted among 87 completely edentulous patients above 40 years of age visiting department of prosthodontics Nepal Medical College. The morphology of maxillary residual ridges were clinically evaluated and classified according to criteria given by American College of Prosthodontists (ACP) classification system. The findings were associated with age, sex, duration of edentulism and complete denture wear. Results: In this study, more than two thirds of the patients belonged to the age group of 60 – 80 years and their mean duration of edentulousness was seen to be 5.7 years. One fifth of the patients were using previous complete dentures. Type A maxillary ridge morphology was found to be the most prevalent. The type of maxillary ridge morphology was not found to be associated with either age or gender of an individual however it varied significantly with length of edentulism and duration of complete denture wears. Conclusions: Within limitations, it can be concluded that maxillary ridge morphology was not associated with age of an individual however the longer duration of edentulism or complete denture use would make the type of ridge morphology more unfavorable.
 Keywords: maxillary ridge; length of edentulism; residual ridge resorption; ridge morphology.

RELATIONSHIP BETWEEN SATISFACTION WITH COMPLETE DENTURES AND BASAL SEAT CHARACTERISTICS

Aim: To investigate the relationship between patients self perceived satisfaction and basal seat characteristics in edentulous patients attending a teaching hospital in Lagos.Materials and Methods: Consecutive edentulous patient seen for 6 months in Lagos University Teaching Hospital, Lagos were recruited for this longitudinal study. The data collected were basal seat characteristics and self perceived satisfaction.Results: A total of 30 patients were seen but only 24 complied with the study protocol. The use of objective assessment in classifying maxillary residual ridge showed that there was a significant association (P=0.045) between the ridge and self perceived satisfaction. There was no significant association between self perceived satisfaction and shape of mandibular ridge, palatal vault and vestibular depth.Conclusion: There was a significant association between shape of maxillary residual ridge and self perceived satisfaction. Objective preclinical assessment of residual ridge may help to project satisfaction and determine treatment option.

上顎の顕著な顎堤吸収に伴う維持・安定不良を改善した有床義歯補綴症例

症例の概要：患者は56歳の女性．上顎総義歯の脱離，下顎顎堤の疼痛および咀嚼障害を主訴に来院した．上顎フラビーガム，上下顎顎堤の大きさの不調和による義歯の脱離，疼痛，咀嚼障害が疑われた症例にブレード人工歯を用いた総義歯を製作し，良好な経過を得た．考察：ニュートラルゾーンの利用およびブレード人工歯を用い，義歯の水平的動揺を可及的に減少させ，さらに人工歯の剪断力を向上し咀嚼困難を訴えた食品の摂取が可能になった結果，満足度が向上したと考える．結論：著名な上顎顎堤吸収および上下顎顎堤の大きさの不調和による総義歯の維持および安定の不良を診断し新義歯の設計と製作を行った結果，主訴の改善と良好な経過を得た．

Viscoelasticity of Human Oral Mucosa

The dynamic behavior of oral soft tissues supporting removable prostheses is not well understood. We hypothesized that the stress and strain of the mucosa exhibited time-dependent behavior under masticatory loadings. Displacement of the mucosa on the maxillary residual ridge was measured in vivo by means of a magnetic actuator/sensor under vertical loading in partially edentulous individuals. Subject-specific finite element models of homogeneous bone and mucosa were constructed based on computed tomography images. A mean initial elastic modulus of 8.0 × 10–5 GPa and relaxation time of 494 sec were obtained from the curve adaptation of the finite element output to the in vivo time-displacement relationship. Delayed increase of the maximum compressive strain on the surface of the mucosa was observed under sustained load, while the maximum strain inside the mucosa was relatively low and uninfluenced by the duration of the load. The compressive stress showed a slight decrease with sustained load, due to stress relaxation of the mucosa. On simulation of cyclic load, the increment of the maximum strain and the evidence of residual strain were revealed after each loading. The results support our hypothesis, and suggest that sustained and repetitive loads accumulate as surface strain on the mucosa.

Changes in the edentulous maxilla in persons wearing implant-retained mandibular overdentures

Statement of Problem: It has been suggested that risk for severe resorption in the anterior maxilla is increased in persons wearing mandibular implant-retained overdentures. However, little information is available about the changes in the edentulous maxilla after mandibular implant treatment. Purpose: This study determined the possible changes in the width of the maxillary residual ridge 6 years after receiving mandibular implant-supported or implant-mucosa–supported overdentures and evaluated the association between the anatomic changes and subjective complaints with maxillary complete dentures. Methods and Material: The subjects for this study (n = 55), enrolled among the participants of a prospective clinical trial, were randomly assigned into 3 groups treated with: (a) implant-supported overdentures on a transmandibular implant system (n = 21); (b) implant-mucosa–supported overdentures on 2 IMZ implants (n = 20); or (c) conventional complete dentures (n = 14). A lingual contact occlusion concept with anterior open bite was used for tooth arrangement in all subjects. Diagnostic casts were made at baseline, and again at the 6-year follow-up. Most prominent points perpendicular to the crest of residual ridge were located in the incisor, canine, and premolar regions, after which the width of the ridge was recorded at these points with a Boley gage. Subjects’ opinions on their dentures were evaluated with a questionnaire. Results: Significant reduction in the width of the ridge was found in all measurement areas (mean difference = 0.4 to 0.6 mm; P <.0001). However, changes were small and not associated with the type of prosthetic restoration in the mandible. In subjects with implant-mucosa–supported overdentures, complaint of loose maxillary denture correlated with the decrement of residual ridge width. Conclusion: The width of residual ridge decreases with time, despite the type of mandibular prosthetic restoration. (J Prosthet Dent 2000;84:43-9.)

Association of residual ridge resorption with systemic factors in home-living elderly subjects

Residual ridge resorption after loss of teeth is a multifactorial oral problem. To examine the association of residual ridge resorption with systemic factors, a cross-sectional study was made of 177 edentulous subjects (43 men and 134 women) aged 76, 81, and 86 years. Resorption in the mandibular and maxillary residual ridges was assessed from panoramic radiographs. The effects on residual ridge resorption of the age, gender, smoking, alcohol intake, body mass index, functioning in daily living, and certain systemic diseases of the subjects were investigated. After adjustment for age and duration of edentulousness, the elderly women had a greater amount of reduction in the mandibular residual ridge than the men (P < 0.001). When the resorption was classified into slight or moderate and severe resorptions, the elderly with asthma were at high risk of severe reduction in the edentulous mandible (odds ratio, 6.0; 95% confidence interval (CI), 1.3-28.2); the elderly women were at high risk of severe resorption in the edentulous mandible, with an odds ratio of 4.5 (95% CI, 1.2-17.1); an inverse association was found between alcohol intake and severe resorption in the edentulous maxilla (odds ratio, 0.4; 95% CI, 0.24.9). This study suggests that asthma due to corticosteroid treatment is to be considered a risk indicator for severe resorption of the edentulous mandible; alcohol intake in the elderly may be related to a lesser degree of resorption of the edentulous maxilla. Female gender is confirmed as a major factor resulting in mandibular atrophy.

リモールディングに関する研究 動的適合試験材を用いた生理的人工歯排列基準

The proper relation of the muscle pressure surface form and surrounding tissue is of great importance. Physiological arrangement of artificial teeth using the trial fitness material and Remolding is a new technique to form the functional contour of the denture.In this study, five edentulous patients with different ridge resorption were selected, the extent of tongue space, comfort and function of the complete dentures constructed by the Remolding technique (R-denture) and conventional method (C-denture) were compared.The results were as follows:1. The tongue space of physiological teeth arrangement was significantly larger than that of posterior teeth which were set on the interalveolar ridge line.2. Three of 5 patients evaluated a definite superiority of chewing, speech, stability and inferiority of food accumulation with the R-denture.3. In selecting a set of dentures for regular use, all 5 patients preferred R-denture.4. The masticatory movements of R-denture was better balanced than that of C-denture in chewing rhythm.5. It is suggested from tomographic diagnosis that the triangle area drawn from the maxillary residual ridge crest and mandibular supporting bone is suitable criterion for the arrangement of artificial posterior teeth.

Rehabilitation of the atrophic edentulous maxilla by bone grafting

Transoral bone grafting is a useful method for the reconstruction of the atrophic maxillary residual ridge in patients who cannot retain complete dentures. The indications, criteria for patient selection, and the technique used have been presented.

Variable denture-limiting structures of the edentulous mouth: Part I. Maxillary border areas

The limiting structures of the edentulous maxillary arch are discussed in terms of potential spaces to be occupied by the denture base. The value of a digital, as well as visual examination of the limiting and supporting structures, is emphasized. Numerous examples of altered structural relationships are indicated. These variables include: (1) the position of the vibrating line in relation to the junction of the hard and soft palate, (2) the position of the pterygoid hamulus in relation to the maxillary tuberosity, (3) the length and direction of the pterygomaxillary notch, (4) the effect of the coronoid process on the retrozygomatic space during opening and excursive mandibular movements, (5) the shape of the anterior segment of the maxillary residual ridge, (6) the consistency and height of attachment of the labial alveolar mucosa, and (7) the size, form, and consistency of the labial, buccal, and pterygomandibular folds.

SAM contourator, model B: An instrument for measuring changes of surface contours

Significant modifications in the SAM contourator, model A, allow for greater ease and rapidity in recording topographic contours of the residual ridge mucosa. A description of these improvements has been presented. A statistical analysis of the combined contourator-planimeter error revealed that the error is area dependent, varying from 1.32 per cent for an area of 62 sq. mm. to 0.40 per cent for an area of 252 sq. mm. The rate at which topographic changes of the maxillary residual ridges occurred after extraction of the first molar tooth was reported for 2 subjects.

A method for measuring topographic changes of the maxillary residual ridge mucosa

the tissues appear moist, pink, and healthy. A criterion of success is ascer­ tained by directing the air syringe at each receptor site. It should be barely visible but should open slightly on air pressure to reveal a deep well formed crypt (Fig. 9 ). When the insert is placed too deeply into the denture, an improperly formed receptor site results. The remedy for this or any other persistent problem is to re­ move the insert, recontour the denture, and permit the tissues to fill in. After re­ pair is completed, the insert may be re­ placed if need for additional retention is apparent. After working with these retentive de­ vices for a period of time, the operator not only becomes facile with them, but acquires talents which help him to em­ ploy them in new and original ways. They may be used in free-end saddle partial dentures when periodontally involved abutment teeth do not offer the required stability. They may also be used to assist in the stabilization of surgical prostheses and obturators. The surgical procedure is minor, the prosthetic technic simple and the results encouraging. The dentist might find the technic useful with older patients since the risk is minimal and the potential benefits gratifying. 2120 Ocean Avenue