Class III Reversion with Immediate Complete Denture and Immediate Implant-Retained Overdenture: Case Report

With the increased life expectancy, complete dentures have been used in the treatment of edentulism progressively. It restores stomatognathic system functions, providing improvements in chewing, aesthetics, and phonetics. The aim was to report an oral rehabilitation of a patient with severe aesthetic and functional impairment, with Angle’s class III malocclusion. The patient sought the extension project of the School of Dentistry of the Federal University of Minas Gerais with aesthetic complaints. After clinical and radiographic evaluation, the proposed planning was immediate complete denture maxilla and immediate implant-retained overdenture in mandible. During clinical evaluation it was observed that the patient was Angle’s III. The rehabilitation was performed as proposed and at the end of the treatment, it was possible to revert the class III occlusal pattern to Angle’s I. The excellent maxillomandibular relationship was achieved, which ensured optimal facial aesthetics and functional condition. It was concluded that the immediate complete dentures and immediate implant-retained overdenture might be beneficial for restoring the aesthetics and function of patients with Angle’s class III malocclusion.

An Alternative Method for Incorporating Fiber Meshes in Complete Upper Dentures

The most commonly used material for constructing complete dentures is polymethyl methacrylate (PMMA). However, the strength characteristics of PMMA, such as impact strength and fatigue strength, are poor, and fracturing of PMMA dentures is a common problem in prosthodontic practice. Reinforcing PMMA with various materials, such as carbon fibers, glass fibers (fiberglass), and ultrahigh modulus polyethylene fibers, has been suggested to strengthen the denture-base material. A common problem encountered when packing the resin on these specimens is fiber slippage beyond the denture edges. The present study proposes an alternative method of incorporating fiber meshes into complete dentures, whereby a thin filament of self-polymerizing resin at the perimeter of the fiber mesh is produced, giving a clear and stable shape to the mesh that fits the upper jaw cast. During placement of the shaped mesh on the cast, a positive-negative relationship is created between the mesh and cast, which immobilizes the mesh during the incorporation process.

Stress area of the mandibular alveolar mucosa under complete denture with linear occlusion at lateral excursion

Background The rocking and instability of a loaded complete denture （CD） during lateral excursion reduce the bearing area under the denture base, causing localized high stress concentrations. This can lead to mucosal tenderness, ulceration, and alveolar bone resorption, and the linear occlusion design was to decrease the lateral force exerted on the denture and to ensure denture stability. But it is not known how the bearing areas of linear occlusal CDs （LOCDs） and anatomic occlusal CDs （AOCDs） differ. The purpose of this study was to analyze and compare the distributions of the high and low vertical stress-bearing areas in the mandibular alveolar mucosa under LOCDs and AOCDs at lateral excursion.Methods Computerized tomography （CT） and finite element analysis were used to establish three-dimensional models of an edentulous maxilla and mandible with severe residual ridge resorption. These models were composed of maxillary and mandibular bone structure, mucosa, and the LOCD or AOCD. Lateral excursion movements of the mandible were simulated and the vertical stress-bearing areas in the mucosa under both mandibular CDs were analyzed using ANSYS 7.0.Results On the working side, the high stress-bearing （-0.07 to -0.1 Mpa） area under the LOCD during lateral excursion was smaller than that under the AOCD, while the medium stress-bearing （-0.03 to -0.07 Mpa） area under the LOCD was 1.33-fold that under the AOCD. The medium stress-bearing area on the non-working side under the LOCD was 2.4-fold that under the AOCD. Therefore, the overall medium vertical stress-bearing area under the LOCD was 20% larger than that under the AOCD.Conclusions During lateral excursion, the medium vertical stress-bearing area under a mandibular LOCD was larger and the high vertical stress-bearing area was smaller than that under an AOCD. Thus, the vertical stress under the LOCD was distributed more evenly and over a wider area than that under the AOCD, thereby improving denture stability.

Effects of short-term adaptation to new complete dentures on perception thresholds for interocclusal thickness in experienced and non-experienced denture wearers

Background The ability of patients to discriminate thickness can change with time after the insertion of new complete dentures, and this adaptation may differ according to the experiences of the patients If so, an education program to reinforce the oral functions may be needed This study was to evaluate patients' ability to discriminate thickness by comparing experienced and non-experienced denture wearers after the insertion of new complete dentures Methods Forty edentulous patients with a skeletal Class Ⅰ jaw relationship without any temporomandibular disturbances were in the study After insertion of new complete dentures, all patients were tested for discrimination threshold for interocclusal thickness The thickness perception test was repeated on days 1, 7, and 30 after the insertion of new dentures The discriminatory ability was assessed with steel and aluminium foils placed between the upper and lower central incisor teeth The records included the duration of wearing dentures The data were subjected to statistical analysis of two-way ANOVA, multiple comparison test and Student's t test Results Discrimination of tactile ability significantly increased over 30 days in experienced denture wearers as compared with non-experienced patients ( P <0 001) The difference in thickness perception threshold was statistically significant between the two groups ( P <0 001) Conclusion Adaptation and denture experience can affect thickness discrimination of complete denture wearers

Estimation of Fatigue Strength of Reinforced Complete Upper Denture Using a Newly Designed Testing Machine: A Laboratory Research Project

In the present study, an aero pneumatic fatigue testing machine for complete dentures was designed, fabricated, and tested for the evaluation of the fatigue life of reinforced complete upper denture (CUD). On completion and testing, it was observed that the machine has the potential of generating reliable number of cyclic data. The machine’s performance was evaluated using test specimens of identical CUDs that were machined in conformity with standard procedures. The fatigue machine compressed the lower dental arch over the upper denture-specimen in centric occlusion, in the same way that the two masticatory muscles pull the lower jaw over the upper jaw during chewing. The incorporation of glass fibres into the CUD using a sandwich technique quadruples the lifespan of the denture (P = 0.004). The low standard deviation, along with the low coefficient of variation (CV) of the group of unreinforced dentures shows the repeatability of the results and the reliability of the machine. The high standard deviation and coefficient of variation of reinforced dentures was expected, since a high variation of results is usually recorded in fibre reinforcement cases. This research confirmed the view that the crack during denture fracture initiates in the anterior palatal area and propagates to the posterior.

Two Cases of Severe Dementia Showing Dramatic Improvement after Denture Placement

Severe dementia, including Alzheimer’s disease, is intractable and progressive. The purpose of this study was to document the improvement observed in two cases of severe dementia after denture placement. The subjects, two women in their 70s with severe dementia, were diagnosed with Alzheimer’s disease by the medical doctors in charge of their cases. In the first case, the subject’s symptoms included severe disorientation, impaired communication, and a tendency to wander. Two weeks after a lower complete denture placement, she was able to greet others. Five weeks later, she was able to communicate and precisely read an analog clock. Her condition continued to improve for at least 3 months. In the second case, the subject’s mouth was always open. She was bedridden in a vegetative state and hardly moved, talked, or laughed;it was impossible to communicate with her. Only a few seconds after an upper complete denture placement, she started to talk, albeit unintelligibly. Two weeks after a lower complete denture placement, she could communicate normally, laugh, and walk without help. Although the underlying mechanism has not yet been clarified, the author hypothesizes that positive signals from the oral area are transferred to the brain as positive stimulation via the trigeminal nerve, the largest cranial nerve.

One-piece implant-supported overdenture in fully edentulous patients: Report of two cases

Dental implants with a reduced diameter can be placed in regions that lack adequate bone volume enabling functional and aesthetic oral rehabilitation without the complicated bone augmentation procedures.This article describes surgical and prosthetic procedures used in oral rehabilitation using Straumann R one-piece Mini Implants(2.4-mm diameter with Optiloc R prosthetic connection system)in two fully edentulous women aged 57 and 74.Both patients presented with severe ridge resorption.Ten one-piece mini dental implants(six on maxillary arch and four on mandibular arch)were placed in each patient to support new complete overdentures.Both patients were delighted with the results and regained their social lives.In addition,stabilized dentures allowed the patients to regain fundamental functions of the mouth:chewing and verbal(speech)and non-verbal(smiling)communication without the fear or difficulty experienced while wearing dentures that can move.In conclusion,mini implants offer an efficient,economical,and less invasive solution,especially for edentulous patients with atrophic bone structure or who cannot undergo complex surgical procedures.

Accuracy evaluation of a new three-dimensional reproduction method of edentulous dental casts, and wax occlusion rims with jaw relation

The article introduces a new method for three-dimensional reproduction of edentulous dental casts,and wax occlusion rims with jaw relation by using a commercial high-speed line laser scanner and reverse engineering software and evaluates the method’s accuracy in vitro.The method comprises three main steps：（i）acquisition of the three-dimensional stereolithography data of maxillary and mandibular edentulous dental casts and wax occlusion rims;（ii）acquisition of the three-dimensional stereolithography data of jaw relations;and（iii）registration of these data with the reverse engineering software and completing reconstruction.To evaluate the accuracy of this method,dental casts and wax occlusion rims of 10 edentulous patients were used.The lengths of eight lines between common anatomic landmarks were measured directly on the casts and occlusion rims by using a vernier caliper and on the three-dimensional computerized images by using the software measurement tool.The direct data were considered as the true values.The paired-samples t-test was used for statistical analysis.The mean differences between the direct and the computerized measurements were mostly less than 0.04 mm and were not significant（P.0.05）.Statistical significance among 10 patients was assessed using one-way analysis of variance（P,0.05）.The result showed that the 10 patients were considered statistically no significant.Therefore,accurate three-dimensional reproduction of the edentulous dental casts,wax occlusion rims,and jaw relations was achieved.The proposed method enables the visualization of occlusion from different views and would help to meet the demand for the computer-aided design of removable complete dentures.

Analysis of the Stress Distribution Pattern of Anatomic and Non-Anatomic Tooth Forms on Maxillary and Mandibular Edentulous Ridges—A Photoelastic Study

Aim: To compare the type of stress distribution pattern occurring with anatomic and non-anatomic tooth forms beneath a complete denture in both maxillary and mandibular arch. Methodology: A photoelastic model of the edentulous maxillary and mandibular ridge was prepared meticulously to simulate the human mandible and maxilla. Two sets of acrylic teeth with anatomic and non-anatomic occlusal forms were used to fabricate upper and lower dentures. A vertical static load of 100 N was applied through the mandibular model to the maxillary model. After load application on the dentures the photoelastic model as well as the upper and lower complete dentures were sectioned in the midline. The sectioned photoelastic model was viewed through a polariscope to observe the fringe pattern indicating varying amounts of stress distribution. In this study, a two-dimensional photoelastic stress analysis technique was utilized. Results: Force per unit area was observed more in anatomic teeth than the non-anatomic counterpart. Hence anatomic tooth forms may increase the possibility of bone resorption rate over a period of time. However, in non-anatomic lower teeth, a decrease in value was observed from posterior to anterior region. Conclusion: Stress of greater magnitude was observed with cuspal teeth whereas non-anatomic (0°) showed slightly less magnitude of stress. Depending upon the clinical situation the clinician needs to choose the type of occlusal tooth forms for edentulous patients.

Treating severe periodontitis with staged load applied implant restoration: A case report

BACKGROUND Because immediate implant surgery is not recommended for patients who have been diagnosed with periodontitis,researchers have treated these patients with a variety of methods,including combining orthodontic and periodontal surgeries as well as implantation.However,these treatments cost time and money for the patient.Although it has been reported that temporary implants released a severe gag reflex in 1 case,only a few studies have documented using temporary implants to treat patients diagnosed with severe periodontitis.CASE SUMMARY The patient was a 49-year-old female who was missing the majority of her teeth and had gingival atrophy and severe alveolar bone atrophy.After being diagnosed with severe periodontitis,the patient underwent staged load applied implant restoration therapy.The first load-bearing stage was carried out immediately by inserting temporary Osstem mini implants.Maxillary teeth were extracted by using the guided bone regeneration technique,and lateral maxillary sinus lifting was conducted on both sides.During the second load-bearing stage,temporary implants were removed,and permanent implants were placed.The resin bridge was segmented during the third load-bearing stage.During the fourth load-bearing stage,the permanent prosthesis was positioned in the patient’s mouth.CONCLUSION By conducting the load-bearing treatment in stages,the patient’s mouth contained restorations throughout the procedure,thus guaranteeing basic function and appearance.

自制食管异物钩取出喉咽部嵌顿义齿1例

1临床资料 患者,男,85岁,因进食时误将脱位的下半口义齿吞咽,导致喉阻塞,不能饮水、进食及说话,颈根部胀痛难忍9小时,气急30分钟,于1999-04-23到我院急诊求治。戴义齿史12年，就诊时生命体征正常，神志清醒，极度痛苦面容，半开口位，口流涎水，中度呼吸困难，颈部僵直头后仰呈强迫固定位。颈前、颈侧触痛。颈部X线正侧位片检查，示喉咽部、食管上端有高密度异物影，阴影后部与第6颈椎椎体前方相抵，阴影底部与第6颈椎下缘平面平齐。心电图检查正常。立即给患者行低流量持续吸氧，30分钟后呼吸困难缓解。