Showing 12 results for Prosthesis
S. Zand , A. zand ,
Volume 15, Issue 1 (3-2002)
Abstract
Tooth loss is a kind of handicap and losing a number of teeth makes an individual susceptible to this disability. Having knowledge about the prevalence of partial tooth loss, provides us with a better understanding of social hygiene. On the other hand, having access to such an information, students can be led properly to treat more prevalent cases. The goal of this retrospective study is to investigate the frequency of partial prosthesis classifications, among patients, referred to Shiraz dental faculty. Sexuality, tooth loss classification and its reason and the presence of additional space were studied about all patients (371 females, 205 males) from (97-98) to the end of (99-2000). The results showed that females were more than males (64.4%), the lower jaw was treated more than the upper jaw (67.9%), dental caries were the most important reason for extraction (55.5%), class I among females (28.79%) and class II mod I among males (29.73%) had the most frequency, meaning that the most cases were free end, so more attention should be paid for the education of free end partial prosthesis, however, preventive steps should be taken to retain abutment teeth.
R. Mosharraf , D. Abtahi , M. Porrabani ,
Volume 16, Issue 4 (1-2004)
Abstract
Statement of Problem:The determination of the dental midline is necessary in most dental procedures.One of the methods to fulfill this goal is to determine the facial midline based on the midpoints of the forehead, nose, upper lip and chin. However, for various reasons, this method has not always been proved successful. In such cases, different techniques, based on the investigations in the edentulous
patients, have been suggested.
Purpose: The aim of this study was to investigate the conformity of some landmarks such as labial frenum, incisive papilla and mid palatal suture with dental and facial midlines among people with natural dentition in order to obtain accurate anatomic landmarks for denture replacement.
Materials and Methods: In this descriptive study, 96 dental students, having all their permanent teeth and without any orthognathic problem, were chosen. For each subject, Alginate impressions and dental casts were prepared. Then, centric occlusion was recorded with a biting wax and the facial mid line was determined on the anterior part of it. The distances from the facial midline to the upper teeth midline,
incisive papilla, labial frenum and mid palatal suture were determined with a special tool and were measured by a VERNIEH two times. In order to analyze the results, Chi- Square and t-student tests were used.
Results: The average of facial midline distance to the upper teeth midline, the labial frenum, the incisive papilla and the mid palatal suture were 0.83±0.60, 0.67±G.54, 0.83±00.63 and 0.81±0.62 mm,respectively. There was no significant difference between males and females. Labial frenum showed the minimum distance to the facial midline, while the incisive papilla had the maximum. There was no significant difference between these anatomic landmarks, in conformity or unconformity with the facial midline
Conclusion: Considering the low percentage of the subjects with complete conformity and the lack of significant differences between these three landmarks, it is suggested that there is no superiority among these landmarks for the determination of facial midline. The similar distances from the facial midline to the incisive papilla and upper teeth midline indicate that using incisive papilla to determine the upper
teeth midline in edentulous patients lead to normal face.
R. Ghoveizi, Gh. Omati Shabestari, A. Mirfazaelian, R. Sadrimanesh, A. Mangali,
Volume 23, Issue 1 (6-2010)
Abstract
A procedure was explained to fabricate a surgical stent to aid the placement of maxillofacial implants for prosthetic auricular rehabilitation. An impression of the defect was made, and a wax pattern of the missing ear completed and evaluated on the patient. The definitive wax prosthesis was processed in clear acrylic resin. Also an occlusal maxillary splint was fabricated and joined to the acrylic resin ear by using an extraoral acrylic resin bar. Surgical stent provides proper orientation of the acrylic resin ear while remaining attached to the maxillary arch. This surgical stent can also be used for radiographic examination.
Hr. Rajati Haghi , S. Nikzad , A. Azari , J. Kashani ,
Volume 23, Issue 2 (10-2010)
Abstract
Background and Aims: Freestanding fixed partial prosthesis is considered the first choice whenever possible. However, anatomical limitations for implants and other reasons may create situation in which it would be preferable to connect the implants to teeth. A biomechanical dilemma in a tooth/implant-supported system comes from dissimilar mobility. This disparity cause the bridge to function as a cantilever and a series of potential problems such as osseointegration loss, screw loosening arise. The aim of this study was to analyze the tooth-implant supported bridges in rigid/non-rigid connectors in cemented prostheses using finite element stress analysis.
Materials and Methods: In this study four three-dimensional models were simulated by use of Solid works software. These models are: 1-RCCP: rigid connector between tooth and implant, 2-NRC CP1: non-rigid connector at mesial side of implant, 3-NRC CP2: non-rigid connector at distal side of second premolar, 4-NRC CP3: non-rigid connector at the middle of pontic, The stress values of four models loaded with vertical forces (150 N) were analyzed.
Results: The maximum stress concentration was located at the crestal bone around implant and stress distribution was more balanced around the teeth except in the model of NRCCP2. Stress distribution was imbalanced in non-rigid connection especially in the NRCCP1 model. The presence of non-rigid connector in bridge increases the stress values in suprastructure and transfers to the adjacent structures. Conclusion: The tooth-implant supported prosthesis should be considered as a valuable prosthetic option. It could be suggested that if tooth and implant abutments are to be used together as fixed prostheses supports, rigid connector is the choice because the prosthesis and implant possess the inherent flexibility to accommodate dissimilar mobility characteristics.
E. Moslehifard, Sh. Safaeian,
Volume 24, Issue 2 (4-2011)
Abstract
Fabrication of dental prosthesis for patients with microstomia has long been a problem for dentists. Microstomia is defined as an abnormally small oral orifice. Prosthetic rehabilitation of microstomia patients presents difficulties at all stages, from the preliminary impressions to fabrication of prosthesis. This study described a method for making impressions for patients with limited opening of the oral cavity which the use of a full-size impression tray was not possible.
M. Alikhasi, H. Siadat, A Monzavi, M. Naseri, S. Sheikhzadeh, F. Taghavi,
Volume 24, Issue 3 (6-2011)
Abstract
Background and Aims: The bond strength between veneer ceramics and zirconia frameworks is the weakest component in the layered ceramics. Due to the possible effect of adding pigments to the core materials on the bond strength between core and veneer as well as the introduction of new ceramic materials in dentistry, the aim of this study was to compare the zirconia core-veneer microtensile bond strength using two ceramic veneers with or without coloring the core.
Materials and Methods: In this experimental study, 12 disc-shaped specimens were fabricated using a manually aided design- manually aided manufactured (MAD/MAM) zirconia core (Zirkonzahn). Two veneering ceramics of Ceram Kiss and Zirkonzahn ICE were also used to veneer the specimens. Half of the Zirkonzahn discs were remained white and the others were colored by shade A2.Then, the discs were cut into microbars (30 for each group) and the microtensile bond strength of the core-veneer was calculated. The specimens were assessed using scanning electron microscopy (SEM) and the data were analyzed using two-way ANOVA and Student's t-test.
Results: Significant differences with respect to veneer layer were found (P<0.001). No significant differences were seen among colored and uncolored cores (P=0.69).
Conclusion: According to the apparent effect of veneering ceramics on the core-veneer bond strength, careful selection of these agents is essential to achieve adequate bond strength between core and veneer to prevent delaminating and chipping failures of zirconia veneered restorations.
Leila Sedighpor, Hoshang Dadgar, Mojgan Naseh, Zahra Soleimani, Somaieh Allahiary,
Volume 25, Issue 4 (1-2013)
Abstract
Background and Aims: Approximately 5% of cancers involve structures of oral cavity. Partial resection of maxilla (maxillectomy) may be performed in these cases. Maxillectomy often results in significant functional disabilities such as inability in mastication, deglutition and speech with adverse impact on psychological status and social life of patients. Obturator prosthesis is a prosthodontic treatment to separate nasal and oral cavities and restore the critical above mentioned functions. The assessment of speech is considered to examine speech function restored by the treatment. The purpose of this study was to evaluate the speech in patients with resected maxilla who have been treated by obturator prosthesis from a pool of related patients in the Prosthodotnics department of dental faculty, Tehran University of Medical Sciences. The evaluation was performed with computer software using sentence intelligibility (SI) test.
Materials and Methods: This cross sectional study was conducted on 10 subjects (23-66 years) referred to the Prosthodontics department of the faculty and received an obturator. After primary examination of the prosthesis, the patients completed SI test in an acoustic room under guidance of a speech therapist. The performed tests were analyzed by the speech therapist. In addition, the SI with and without the prosthesis was evaluate by lay audience. The statistical analyses were performed using Wilcoxon-signed rank test and Weighted Kappa.
Results: Significant differences were found between SI tests with and without the obturators (P<0.001). Two of 10 patients showed problems in speech function using obturator.
Conclusion: Within the limitations of the present study, obturators had significant effect on improvement of the speech outcomes of examined patients. Improvement of the quality of life could be predicted.
Marzieh Alikhasi, Pooya Aslani,
Volume 26, Issue 2 (5-2013)
Abstract
Background and Aims The purpose of this study was to evaluate the survival rate, mean bone loss and post operative complication of implants inserted in All-on-4 technique .
Materials and Methods: The literature was searched using keywords angled implant, All-on-4, tilted implant and graftless technique in the last 10 years (2001 to 2011) and clinical trial article that evaluated survival rate and mean bone loss around axial and tilted implants in All-on-4 technique was selected and evaluated. A total of 73 articles were found by searching. After evaluation of titles and abstracts, finally 10 clinical trial, that were fully consistent with including criteria such as mean of bone loss and survival rate was selected and evaluated.
Conclusion: Results showed that the survival rate (96-100%) and mean bone loss (0.34-1.9 mm) with All-on-4 technique in immediate loading is comparable with other implant support treatment plan. Comparison of implant survival and bone loss in axial and tilted implant in All-on-4 system is shown this treatment plan has consistent result with other conventional implant support prosthesis. Also, postoperative complication including fractures of the acrylic temporary prosthesis, detachment of the teeth, abutment or prosthesis screw loosening have been reported with All-on-4 technique.
Bahram Kouhnavard, Hosseinali Mahgoli, Somayeh Bolghanabadi, Mohsen Yazdan Aval, Maryam Rostami Aghdam Shendi, Malihe Kolahdouzi,
Volume 31, Issue 2 (9-2018)
Abstract
Background and Aims: Making dental prostheses is sensitive and accurate work and requires powerful and skilled hands. Because of this, the dental prosthesis technicians may suffer harmful effects such as stress and fatigue during the course. The aim of this study was to investigate fatigue, stress and job performance and their relationship with some demographic variables in this community.
Materials and Methods: The present study was cross-sectional and done in 2016. The study population was a group of dental prosthesis technicians that had participated in a national congress in Tehran. Sampling was done by census Two standardized questionnaires on the subjects of fatigue and stress which were distributed among 100 female and male participants and sampling was done by census. Then, the obtained data was analyzed using SPSS16 software and applying descriptive statistics, Pearson correlation test, and ANOVA, T-test.
Results: From the 100 samples, there were 16 females and 84 males with mean age 34.71±7.90 and average work experience of 10.82± 9.01 years. 82 percent of the subjects were married and 42 percent of them were smokers. The results showed that 100 percent of dental prostheses technicians were facing with moderate to severe stresses. The stress and fatigue scores in married ones were higher than the single ones. The results showed a significant relationship between smoking, stress, and fatigue scores (P<0.05).
Conclusion: According to the high level of job stress in the dental prostheses technicians, this problem must be considered, minimized, and more attention should be paid to their psychological and emotional problems.
Sasan Rasaeipour, Mahroo Vojdani, Safoura Ghodsi,
Volume 31, Issue 3 (11-2018)
Abstract
Background and Aims: Cleft lip and palate is among challenging dentistry problems that calls for a multidisciplinary treatment approach. The treatment protocols in adults aims to improve function, appearance, and psychological conditions. The present article aimed in introducing the procedure of conventional prosthesis application for treatment of an adult patient focusing on complicated intra-operatory challenges.
Materials and Methods: A 52-year-old male patient was referred for correcting his functional deficiency resulted from bilateral cleft lip and palate. After surgical stent fabrication and vestibuloplasty, transitional prosthesis was fabricated using “Melted-sugar method”. Six month later, Richmond copings and fixed prostheses were made and the treatment was completed by delivery of mandibular removable partial prosthesis and maxillary obturator. Finding the correct position of hard palate, not interfering with normal phonetic, and hollowing his obturator, along with stablishing correct vertical dimension were among several challenges call for special considerations.
Conclusion: Following sound procedure, the conventional prosthetic treatment could be considered as an acceptable and applicable treatment option for adults suffering from untreated cleft palate, who are not good candidates for more complicated treatment procedures.
Sara Mogharrabi, Safoura Ghodsi, Majed Kooti, Asadallah Ahmadzadeh, Neshatafarin Manouchehri,
Volume 33, Issue 3 (10-2020)
Abstract
Background and Aims: Removable partial denture (RPD) is a common treatment to restore partially edentulous areas; however, a limited number of studies have been made on oral hygiene habits among patients with RPD. The aim of this study was to evaluate the patients’ knowledge about various cleaning methods of RPD to consciously improve hygienic habits of the patients.
Materials and Methods: This study was a cross-sectional study performed on 96 RPD patients referred to Jundishapur faculty of dentistry from 1395 to 1396. Demographic data namely age, sex, level of education, and other information about general health status, duration of dentures usage, and denture cleaning frequency were taken by the census through questionnaires. The descriptive statistics, chi-square, and T-test were used for statistical analysisof data (P<0.05).
Results: The patient age, sex, and smoking habits had significant effects on the prosthesis maintenance habits (P<0.05). The patients over 50 years of age, females, and nonsmokers significantly preferred dipping method over other RPD storage methods (P<0.05). The frequency of denture cleaning was significantly greater in males (53.3%) compared to females (23.9%) (P<0.05).
Conclusion: According to the results of this study, most RPD patients did not clean their dentures appropriately and have little knowledge on how to maintain and clean them. Regular and periodic recall and written instructions might be helpful to improve patients' awareness on proper cleaning and maintenance of partial dentures.
Seyed Ramin Nourbakhsh, Hamideh Yosefpour, Freshteh Osmani,
Volume 34, Issue 0 (5-2021)
Abstract
Background and Aims: In impacted third molar surgery, panoramic radiography is a preliminary technique for assessing the consequences associated with inferior alveolar nerve injury. However, this technique cannot provide enough information to determine the true risk in all cases. The aim of this study was to compare the accuracy of panoramic and CBCT radiographs in evaluating the relationship between the mandibular impacted third molars and the inferior alveolar nerve.
Materials and Methods: In this cross-sectional study, the relationship between mandibular third molar and inferior alveolar nerve in 15 patients referred to the oral and maxillofacial radiology department of Birjand dental school including 20 mandibular third molars were evaluated using two panoramic and CBCT radiographs. Data were analyzed using descriptive statistics and chi-square test and sensitivity analysis in SPSS22.
Results: In the evaluation of the teeth using panoramic radiography, the highest frequency was related to root darkening (65%) and root deflection (65%), and the lowest frequency was related to root narrowing (20%) and canal deviation (5%). The highest sensitivity of panoramic criteria was related to the root darkening with 100% sensitivity and the lowest sensitivity was related to the canal deviation with 17% sensitivity. On the other hand, the highest specificity of panoramic criteria between the mandibular third molars with the inferior alveolar nervewas was related to the two criteria of bifid apex and canal deviation with 100% specificity. The lowest specificity was related to the root deflection with 21% of specificity.
Conclusion: According to the results of this study, the probability of observing relationship between the mandibular third molars with the inferior alveolar nerve in CBCT radiography was very high.
