Partial Edentulous Patients Research Articles

Technical and Biological Complications Related to Crown to Implant Ratio

To review the occurrence of prosthetic failure and biological complications with respect to the crown to implant (C/I) ratio. Accurate search was made on the subject C/I ratio with the following criteria: (1) studies on humans with data on prosthetic failure and/or biological complications related to C/I ratio; (2) partial edentulous patients; (3) randomized clinical trials, prospective, longitudinal, retrospective, and multicenter studies with a minimum of 48 months mean follow-up; (4) language: English; (5) radiographic measurements by peri-apical x-ray; (6) implant material: titanium; and (7) no implant type selection was applied. Six articles were considered eligible for full-text analysis. Unfavorable C/I ratio can be considered a potential risk factor for single crown and abutment loosening (C/I ratio ≥ 1.46) and abutment fractures in posterior areas (C/I ratio ≥ 2.01). Despite the limited data, high C/I ratio may be related to some prosthetic failures. Unfavorable C/I ratio does not affect biological complications and implant failure.

Occurrence Regions and Sites of Peri-implant Inflammation With Bone Resorption in Partially-edentulous Patients

Aim: The aim of this study was to clarify the occurrence regions and sites of peri-implant bone resorption and inflammation in partially-edentulous patients.Methods: Five hundred one partially-edentulous patients with 738 implants in function for more than 5 years were included in this study for the evaluation of the bone resorption by using dental radiograph and probing. Considering physiological bone remodeling, the mean mesio-distal bone resorption around the implant was measured on dental radiograph.Results: In 65 patients (13.0% of the total patients) with 76 implants (10.3% of the total implants), peri-implant bone resorption was identified. The mean functional loading time of these implants was 8.4 years. Occurrence regions were frequently found in the molar regions in maxilla (15.4%) and the molar region in mandible (10.0%) In these leisions detected radiologically, the bleeding on probing was seen in 95.2% of the buccal sites in mandibular molar regions, 70.0% of the palatal sites in maxillary molar regions and 56.7% of the buccal sites in maxillary molar regions with statistically significant differences.Conclusion: From the limitation of the information in this study, it was concluded that the sites that tend to be vulnerable to peri-implant inflammation were the buccal site in mandible, and the buccal and palatal sites in maxilla.

실패 증례 분석을 통한 국소의치 제작 시 주의사항

Removable partial denture for oral function recovery of partial edentulous patients is a complicated treatment because the dentist should consider both hard tissue and soft tissue. Removable partial denture produced without consideration of precise design for each component and rotation of denture may cause fracture, deformation or loss of abutment teeth. In case of failure to achieve a proper denture, the reason of failure should be analyzed and the result must be applied to later RPD cases. Finding the solutions through the failed denture cases will help patients use their dentures more comfortably and keep their sound residual teeth and tissue longer.

Patient-specific finite element analysis of viscoelastic masticatory mucosa

The purpose of this study was to analyze the stress and strain inside of the oral mucosa in partially-edentulous patients. The patient-specific finite element models of the mucosa and the bone were constructed using the CT images and in-vivo surface measurement during a continuous load. The mean initial shear modulus of 8.3 × 10–5 (GPa) and the mean relaxation time of 503 (s) were determined as the viscoelastic properties of the mucosa. The increase of the highest maximum compressive strain during the continuous loading was observed in all the patients, however; the intensity of strain was not in accordance with the thickness of the mucosa. It is suggested that the variations of the morphology and the initial modulus of the mucosa should be considered in the mathematical approaches to detect the mechanical responses of the oral mucosa.

Assessment of knowledge related to implant dentistry in dental practitioners of north Karnataka region, India

Purpose of the Study: Dental implants are becoming a popular choice replacing the missing teeth. Use of dental implant over last decade has increased. Today, dental implant treatment is highly predictable and renders itself as a valid option for completely or partial edentulous patients. Nowadays, it is not uncommon to see a patient walking into a practice with already implant being placed in him or asking for implants placement. Therefore, it has become mandatory for the general dental practitioner to be familiar with dental implants. This study was aimed to assess the basic knowledge about dental implants among private dental practitioners of North Karnataka region, India. Materials and Methods: Multiple choice questionnaires were framed regarding some basic knowledge about dental implants. Dental practitioners were asked record their responses. Simple percentage evaluation was done for the responses obtained. This data formed the basis for assessment. Results: The results are reported by summarizing responses to each of the 15 questions in the survey. Conclusion: Highly didactic clinical and laboratory dental implant training modules should be structured and implemented at undergraduate level as well as post-doctoral level. This will enable private dental practitioner, to practice dental implantology with confidence.

PHYSIOLOGICAL IN VIVO LOADING MEASURING IN ALVEOLAR DISTRACTION

Loading evaluation in biomechanics is of the most concern if reliable results are expected. A key aspect in the mechanical design of an alveolar distractor is the accurate evaluation of physiological loading for computer simulation and effective modeling. Very few information and previous works are available about this subject. A stainless steel load cell with strain gauges has been developed and manufactured, in order to get accurate values of physiological loading. The cell was attached to splints, like those used in orthodontia. The load cell was calibrated and then an "in vivo" test was carried out on four partially-edentulous patients. Load digital registers were obtained for three cases in each patient: Tongue protrusion, lower or upper lips retraction and a combination of tongue and lips during the vocalization. Records show that it is possible to interpret quantitatively the load proportionality according to the tongue and lip physiological movements. From the loads magnitude differences in four patients, it can be observed that the morphological factor or occlusion differences affect both the loads size of the tongue protrusion muscles and lip retraction due to the orbicular muscles which can vary slightly or significantly. Further studies are been carried out by considering other kind of patients suffering different pathologies.

EVALUATION OF PATIENT FEATURES AND CLINICAL OUTCOMES IN PARTIAL EDENTULOUS PATIENTS SUFFERING IMPLANT SURGERY

Background: Dental implants have been used to restore teeth loss in Thua Thien Hue province. However, no study reports on the outcome of using implants for this purpose. The aim of this study was evaluated the patient features and clinical outcome in partial edentulous patients suffering implant surgery. Materials and methods: 34 patients treated with 62 implants Mis from 01/01/2009 to 30/12/2010 were prospective analyzed with regard to implant success after 3 to 6 months follow-up. Results: Patients are mostly female patients, the most common age group is 18-39. Tooth loss is often mandibular first molars, mainly due to caries. Without significant complications occurred in the course of surgery, good initial stability accounts for 96.77%. After follow-up periods of 3 to 6 months, good osseointegration is 93.55%. Conclusions: Dental implant surgery is highly successful treatment, restores funtions and esthetics for patients with tooth loss.

Bone density assessment of oral implant sites using texture parameters

The primary objective of this article is to compare the performance of various textural features, computed from dental CT in detecting bone quality (density) at local implant recipient sites and to investigate the correlation between local bone density measured using CT machine and texture features. These findings may provide the clinician with guidelines for dental implant surgical procedures (i.e. to determine whether a one-stage or a two-stage protocol is required). Fifty-five patients were subjected to clinical CT to obtain the CT number and texture-based architectural parameters, respectively. In each site, texture features were extracted using grey level co-occurrence matrices, run-length matrices, histogram and ridgelet-based statistical co-occurrence analysis. The findings are compared with Hounsfield Units measured from the CT machine at local implant sites, which is a standard reference. Then Bayes classifier is used to build the mapping relationships between these features and quality of the bone, respectively. A very difficult problem in classification techniques is the choice of features to distinguish between classes. However, the performance of any classifier is not optimised when all features are used. The feature optimisation problem is addressed using classical sequential methods and floating search algorithms in terms of the best recognition rate and the optimal number of features. Testing this on a series of 90-image sections of trabecular bone with normal, partial and total edentulous patients correctly classified over 90% of the porous bone group with an overall accuracy of 92%. Classical sequential methods and floating search algorithms are compared in terms of the best recognition rate achieved and optimum number of features. The classification performance of 93% is achieved in sequential floating backward search and sequential floating forward search with optimal features compared with sequential methods.

Custom-Made Radiographic Template, Computed Tomography, and Computer-Assisted Flapless Surgery for Treatment Planning in Partial Edentulous Patients: A Prospective 12-Month Study

It was proposed that technologies derived from computer-aided design (CAD)/computer-aided manufacturing (CAM) and computed tomography may be useful for flapless implant treatment procedures. However, most of the studies examining the effectiveness of this method were performed in fully edentulous patients, with little or no attention paid to partially edentulous patients. The aims of this study were 1) to evaluate the concept of computer-assisted implant placement including a treatment planning procedure based on computed tomography scan images by use of a flapless surgical approach in partially edentulous cases and 2) to validate the reliability of this concept in a prospective 12-month clinical study. Sixteen patients with partially edentulous areas in their mandibles were included in this study. A total of 57 implants were inserted by use of a CAD/CAM drill template, specially designed for flapless implant surgery. To assess the degree of pain and discomfort, the patients were examined at 2 days and 1 week after surgery. Patient satisfaction and implant functionality were further evaluated at follow-up intervals of 1, 3, 6, and 12 months postoperatively. A specially designed visual analog scale was used for data acquisition. The mean pain score on the visual analog scale at follow-up was within the range for little or no pain. Two implants failed early in 1 patient. All of the other implants were in a good functional state throughout the study. The mean marginal bone loss after 1 year of follow-up was 0.6 mm (SD, 0.2) mesially and 0.5 mm (SD, 0.1) distally. This prospective study showed that the use of CAD/CAM technology and flapless implant surgery may be considered reliable for partial edentulous patients.

Clinical Viability for Immediate Loading of Dental Implants

The treatment with implants aims to obtain a direct interface between bone and implant. The implant is kept load-free during 4 to 6 months in the 2-stage procedure, which is considered a requisite for osseointegration. However, this period is based on empirical principles and uncomfortable for patient. So, the immediate loading protocol was suggested to submit implants to occlusal function after placement. This protocol has been applied for several conditions of edentulism. The aim of this study was to evaluate the treatment alternatives for immediate loading of complete and partial edentulous patients. In general, the studies have demonstrated high previsibility for rehabilitation of complete edentulous arches with full-arch, implant-supported prosthesis. The rehabilitation with immediate loading for maxillary overdenture is questionable because there is no longitudinal study in literature. The studies with partial edentulous arches have demonstrated high success rates for implants placed in the mandibular and maxillary anterior region. Additional care is recommended for posterior region mainly in the maxillary arch, and further studies are suggested to corroborate this treatment.

유한요소법을 이용한 하이브리드형 임플란트의 응력해석

Abstract After scientific verification of the osteointegration of dental implants, the overall efficiency of dental implants has been generally accepted. Thus, implants now play a major role in the clinical treatment of an edentulous mandible, and in the prosthetic maintenance equipment for partial edentulous mandible patients. Yet, for the successful long-term maintenance of implants, careful consideration of the bio-mechanics is needed to ensure that the maximum stress in the mandible as a result of chewing is maintained under a critical value. Accordingly, this study focuses on reducing the maximum stresses in an implanted mandible, especially in the cortical bone. Thus, the stresses in the implant and mandible are analyzed using finite element packages, including I-DEAS and NISA II/DISPLAY III, using a local zooming technique for a concentrated stress analysis. In addition, the von-Mises stress and principal stress in the mandible are both checked to determine the best combination.

Evaluation of stress induced in peri-implant bone tissue by misfit in multi-implant prosthesis

The objective of the present work was to use numerical analysis to evaluate the relevance of stress states induced in peri-implant bone tissue by a misfit in a dental fixed prosthesis. Misfits in both mesial-distal and lingual-labial directions were considered to investigate a realistic configuration of the problem. A finite element model of a portion of a mandible with two implants connected by a gold alloy bar was defined on the basis of the morphometric data of a partial edentulous patient. A specific procedure was developed to represent the bar-implant coupling in the case of a misalignment between the implant and central axes of the anchoring site to the bar. Loading conditions related to occlusal forces were also considered. The numerical analysis of the implant-bridge misfit showed significant stress effects on the peri-implant bone tissue. For the specific prosthetic configuration considered, the maximum compressive stress was in the range of 40-60 MPa, depending on the misfit considered. The stress level was largely affected by the axial and bending stiffness characteristics of bar-implant compound. Stress analysis using numerical methods made it possible to estimate stress states with high accuracy in terms of intensity and location. For the case considered, stress induced by misfit was comparable with that related to occlusal forces. Therefore, a possible bar-implant misfit should be carefully considered to ensure the reliability of the prosthetic system.

The study of the peri-inplant soft tissue around osseointegrated implants in partial edentulous patients

The study of the peri-inplant soft tissue around osseointegrated implants in partial edentulous patients

Book Reviews

Book reviewed in this article:DENTAL FLUORIDE CHEMISTRY, by Alan F. Berndt and Robert I. Stearns. Springfield, Charles C. ThomasTHE CRANIUM OF THE NEWBORN INFANT. AN ATLAS OF TOMOGRAPHY AND ANATOMICAL SECTIONS, by R. H. Pierce, M. W. Mainen, and J. F. BosmaMANAGEMENT OF WAR INJURIES TO THE JAWS AND RELATED STRUCTURES, edited by James F. KellyPROSTHODONTIC TREATMENT FOR PARTIALLY EDENTULOUS PATIENTS, edited by George A., Zarb, Bo Bergman, Joseph A. Clayton, and Hugh F. MacKayTYLMAN'S THEORY AND PRACTICE OF FIXED PROSTHODONTICS, by S. D. Tylman and W. F. P. MaloneSELF ASSESSMENT MANUAL 3. CLINICAL DENTISTRY, by A. S. Prophet and A. G. AlexanderBIENNIAL REPORT, 1976–1978, OF THE INSTITUTE OF DENTAL RESEARCHPRECISION ATTACHMENTS. DENTAL PRACTITIONERS HANDBOOK NO. 7, by G. E. Ray. Bristol, John WrightAPPLICATION OF THE INTERNATIONAL CLASSIFICATION OF DISEASES TO DENTISTRY AND STOMATOLOGY ICD‐DAGUIDE TO DENTAL MATERIALS AND DEVICES, 1976–1978STRESS AND RELAXATION: APPLICATION TO DENTISTRY, by Donald R. Morse and Merrick L. Furst. Springfield, Charles C. Thomas, 1978HOSPITAL DENTAL PRACTICE‐A MANUAL, edited by Raymond F. Zambito. New York, Medical Examination Publishing Company Inc., 1978HANDBOOK OF MEDICAL EMERGENCIES IN THE DENTAL OFFICE, by Stanley F. Malamed. Saint LouisA HANDBOOK FOR DENTAL HYGIENISTS, by W. J. N. Collins, J. O. Forrest, and T. F. WalshSELF ASSESSMENT MANUAL 2. ORAL MEDICINE AND DIAGNOSIS, by Bertram Cohen, David K. Mason, and David E. PoswilloPROGRESS IN CARIES PREVENTION. CARIES RESEARCH, Vol. 12, Supplement 1, edited by Y. Ericsson. Basel, S. Karger