Prosthetic Factors Research Articles

Characterization of Chronic Mechanical Irritation in Oral Cancer.

Objective. Oral mucosa could host many lesions originated by chronic mechanical irritation (CMI) from teeth or dentures, and it has been proposed as risk factor for oral cancer. Nevertheless, the features of CMI factors in oral cancer and other lesions are not assessed. The aim of this study is to describe CMI features regarding type (dental, prosthetic, and/or functional), localization, and time span. Materials and Methods. Three groups were studied in this cross-sectional study: Oral Cancer (OC); Chronic Traumatic Ulcer (CTU); and Benign Irritative Mechanical Lesions (BIML). All sources of mechanical irritation were included: dental, prosthetic, and functional. Results. 285 patients (176 females, 109 males) were studied: OC = 38, CTU = 44, and BIML = 203. The most frequent CMI factor was dental, followed by functional and prosthetic in all groups; 76.5% (n = 218) presented functional factors. Buccal mucosa (45%) and tongue (42%) were the most affected sites. Time of action of CMI displayed statistically significant differences between BIML, CTU, and OC groups, with a mean of 21, 33, and 49 months, respectively. Conclusions. CMI should be properly recorded with as much detail as alcohol and tobacco consumption. CMI associated lesions are produced by dental or prosthetic factors, usually in relation to functional factors, involving mainly tongue and buccal mucosa.

Deep pain sensitivity is correlated with oral-health-related quality of life but not with prosthetic factors in complete denture wearers

ABSTRACTLow pressure Pain Threshold (PPT) is considered a risk factor for Temporomandibular Disorders (TMD) and is influenced by psychological variables. Objectives To correlate deep pain sensitivity of masticatory muscles with prosthetic factors and Oral-Health-Related Quality of Life (OHRQoL) in completely edentulous subjects.Material and Methods A total of 29 complete denture wearers were recruited. The variables were: a) Pressure Pain Threshold (PPT) of the masseter and temporalis; b) retention, stability, and tooth wear of dentures; c) Vertical Dimension of Occlusion (VDO); d) Oral Health Impact Profile (OHIP) adapted to orofacial pain. The Kolmogorov-Smirnov test, the Pearson Product-Moment correlation coefficient, the Spearman Rank correlation coefficient, the Point-Biserial correlation coefficient, and the Bonferroni correction (α=1%) were applied to the data.Results The mean age (standard deviation) of the participants was of 70.1 years (9.5) and 82% of them were females. There were no significant correlations with prosthetic factors, but significant negative correlations were found between the OHIP and the PPT of the anterior temporalis (r=-0.50, 95% CI-0.73 to 0.17, p=0.005).Discussion The deep pain sensitivity of masticatory muscles in complete dentures wearers is associated with OHRQoL, but not with prosthetic factors.

Association between prosthetic factors and temporomandibular disorders in complete denture wearers

The purpose of this study was to investigate the prevalence of temporomandibular disorders (TMD) in denture wearers and the association between prosthetic factors and this condition. There is no consensus about the relationship between prosthetic factors and TMD among denture wearers. The sample was composed of 92 patients wearing both maxillary and mandibular complete dentures. The Research Diagnostic Criteria for TMD (RDC/TMD) were adopted for patient examination. Objective evaluation of denture quality was determined by analysis of retention and stability of mandibular denture, interocclusal distance, articulation and occlusion. Association between denture quality and TMD diagnosis was analysed using chi-square and Fisher's exact tests. 37.4% of the patients presented TMD. Denture quality was not significantly associated with the presence of TMD: mandibular retention (p = 0.466); mandibular stability (p = 0.466); interocclusal distance (p = 0.328); centric relation (p = 0.175); and balanced occlusion (p = 0.56). Within the scope of this case-controlled cross-sectional study, no robust association between prosthetic factors and TMD was found.

Influence of crown–implant ratio on implant success rates and crestal bone levels: a 36‐month follow‐up prospective study

The aim of this prospective study was to determine how the crown-implant ratio (C/I ratio) influences crestal bone loss and implant success rates after a 3-year follow-up, using implants with a sintered porous surface (SPS). On the basis of preestablished inclusion and exclusion criteria, 151 of a cohort of 160 patients with single or partial edentulism were selected as eligible for the study. The 151 patients were treated consecutively from 2005 to 2007 using 280 SPS implants, which were restored with a single crown or a partial fixed denture. The data collection included both clinical and anatomical C/I ratios; other implant prosthetic factors were also recorded. Implants were divided into three groups according to the C/I ratio. Clinical and radiographic examinations were scheduled over a 36-month follow-up of functional loading according to a well-established protocol generally applied to determine implant success rates and crestal bone levels. Statistical analysis was used to determine any significant differences or correlations (P = 0.05). A total of 259 SPS implants in 136 patients were followed up for 36 months. According to the success criteria, the overall implant-based success rate was 98.1%, and the mean peri-implant bone loss (PBL) was 0.48 ± 0.29 mm. Statistical analysis revealed significant correlation between implant success rate and C/I ratio (P < 0.05) and between PBL and C/I ratio (P < 0.05). The critical threshold value of the anatomical and clinical C/I ratio for avoiding excessive bone loss or implant failure was 3.10 and 3.40. This prospective cohort study revealed that SPS implants offer a predictable solution for implant prosthetic rehabilitation in patients with edentulism characterized by different alveolar bone atrophy. From the biomechanical point of view, the C/I ratio would appear to be the main parameter capable of influencing implant success and crestal bone loss. Consequently, it is important not to exceed the threshold values in order to avoid excessive stress at the bone-implant interface capable of resulting in excessive crestal bone loss or implant failure.

Relationship between Oral Health‐Related Quality of Life, Satisfaction, and Personality in Patients with Prosthetic Rehabilitations

This study investigated the relationship between oral health-related quality of life, satisfaction with dentition, and personality profiles among patients with fixed and/or removable prosthetic rehabilitations. Thirty-seven patients (13 males, 24 females; mean age 37.6 +/- 13.3 years) with fitted prosthetic rehabilitations and 37 controls who matched the patients by age and gender were recruited into the study. The Dental Impact on Daily Living (DIDL) questionnaire was used to assess dental impacts on daily living and satisfaction with the dentition. The Oral Health Impact Profile (OHIP) was used to measure self-reported discomfort, disability, and dysfunction caused by oral conditions. Oral health-related quality of life was assessed by the United Kingdom Oral Health-Related Quality of Life (OHQoL-UK) measure. Moreover, the NEO five-factor inventory was used to assess participants' personality profiles. Prosthetic factors had no relationship to the DIDL, OHIP, and OHQoL-UK scores. Patients with the least oral health impacts had better oral health-related quality of life (p= 0.023, r =-0.37), higher levels of total satisfaction, and satisfaction with appearance, pain, oral comfort, general performance, and eating (p < 0.05, r =-0.79, -0.35, -0.59, -0.56, -0.58, and -0.50, respectively). Patients with better oral health-related quality of life (QoL) had higher total satisfaction, satisfaction with oral comfort, general performance, and eating (p < 0.05, r = 0.34, 0.39, 0.33, and 0.37, respectively). Patients with lower neuroticism scores had less oral health impact (p= 0.006, r = 0.44), better oral health-related QoL (p= 0.032, r =-0.35), higher total satisfaction, satisfaction with appearance, pain, oral comfort, and eating (p < 0.05, r =-0.58, -0.35, -0.33, -0.39, and -0.35, respectively). Patients' satisfaction with their dentition and prosthetic rehabilitations has positive effects on oral health-related QoL and oral health impacts and improves patients' daily living and dental perceptions. Neuroticism might influence and predict patients' satisfaction with their dentition, oral health impacts, and oral health-related QoL. Satisfaction with the dentition might predict a patient's level of neuroticism.

Obturator prosthesis for armany's class VI maxillary defect: A clinical report

Maxillary defects are created by surgical treatment of benign or malignant neoplasms, congenital malformation and by trauma. The size and location of the defects influence the degree of impairment and difficulty in prosthetic rehabilitation. Armany's Class VI maxillary defect is rare in occurrence and rehabilitation of such patients pressent many challenges. Such defects preclude masticatory function, speech, deglutition and facial esthetics. These patients after undergoing the surgery are psychologically and functionally compromised; therefore multidisciplinary approach comprising psychological and prosthetic factors should be followed.

Prosthetics May Not Affect the Survival or Complication Rates of Short Implants

Influence of prosthetic parameters on the survival and complication rates of short implants. Tawil G, Aboujaoude N, Younan R. Int J Oral Maxillofac Implants 2006;21(2):275-82 . 4 To determine the influence of prosthetic factors on the survival and complication rates of short implants. Information not available Case series

Aerodynamic and Sound Intensity Measurements in Tracheoesophageal Voice

Background: In laryngectomized patients, tracheoesophageal voice generally provides a better voice quality than esophageal voice. Understanding the aerodynamics of voice production in patients with a voice prosthesis is important for optimizing prosthetic designs and successful voice rehabilitation. Objectives: To measure the aerodynamics and sound intensity in tracheoesophageal voice production. Study Design and Methods: We built a special setup, which consisted of a Pentium 200 MHz computer with an AD-DA interface card and Labview 4.01 software. In an oral/nasal mask we constructed several mass flow sensors and a microphone. This measured both the oral airflow and the level of sound. For the measurement of endotracheal pressure, which is the driving force behind the airflow, we used a transducer which was connected to the tracheostoma. The endoesophageal pressure was measured at the level of the prosthesis in the esophagus by a Mikrotip transducer. Using this we could determine how much the voice prosthesis contributes to the overall pressure drop of the phonatory tract. Furthermore, the average airflow rate as a function of the sound pressure levels could be determined. Results: In our population, 6 out of 7 patients showed a positive relationship between trans-source airflow and generated sound intensity. We compared our prosthesis pressure drop values with in vitro data and found that there are some differences, possibly due to difference in age of the prosthesis and physiological circumstances in vivo. The overall contribution of the voice prosthesis to the airway resistance depends on the level of phonation and the type of device. In our patient group it is apparent that the pharyngoesophageal (PE) segment has the greatest share of the total pressure drop, especially at higher airflow rates. We measured a 27% pressure drop in airflow over the voice prosthesis. Different tracheostoma occlusion methods did not have any effect on the aerodynamics and sound intensity. One patient that had had a jejunal graft for reconstruction showed, not unexpectedly, extremely different aerodynamic values. We were unable to define optimal airflow rates or optimal resistance values for sound production in the PE segment. Conclusion: The aerodynamic characteristics of voice production in laryngectomized patients with voice prostheses are determined by both prosthetic factors and PE segment tissue factors. In our patient group the PE segment is responsible for the greatest pressure drop. We found no significant difference in pressure drop and sound intensity for different tracheostoma occlusion methods.

Host factors that affect outcome of total hip arthroplasty

Investigations into risk factors influencing success of total hip arthroplasty have focused primarily on the type of prosthesis and surgical technique. Rapid polyethylene wear was found to be an important contributor to aseptic fixation failure. However, because prosthesis design is now near perfect, the effect of prosthesis-related factors on survival of the implant has declined. The extreme variability in functional outcomes and revision rates, even within groups implanted with the same prosthesis and at the same institution, indicates the importance of looking beyond prosthetic factors. In today's Lancet Seneki Kobayashi and colleagues report that the two most important host factors contributing to the survival of the hip implant are poor bone quality (manifest as atrophic osteoarthritis) and poor structure of the hip (stovepipe canal). Poor bone quality or hip structure as risk factors affecting survival of total-hip arthroplastyIn THA, the critical risk factors are poor bone quality, which manifests as atrophic osteoarthrosis, for socket survival and poor bone structure for femoral-prosthesis survival. To ensure longer durability of THAs, these factors should be assessed further and efforts, especially biological initiatives, should be made to resolve them. Full-Text PDF

Dental factors in the genesis of squamous cell carcinoma of the oral cavity

This study investigated the role of dental factors in the genesis of squamous cell carcinomas of the oral cavity. 99 newly diagnosed patients with advanced head and neck cancer were evaluated for potential demographic, dental and prosthetic risk factors. Patients with extra-oral malignancies were used as controls in the analysis of dental factors in patients with intra-oral cancers. We performed multiple comparisons of these factors against the primary tumour sites. An analysis of dental and prosthetic factors and patients with intra-oral versus extra-oral tumours revealed no significant differences. However, all 28 intra-oral malignancies arose in areas in contact with teeth and/or appliances. For example, all 10 oral tongue lesions arose on the lateral borders and all six floor of (drop) mouth primary tumours developed at the flange extension of a lower denture. Patients with partial or full dentures had significantly lower node (N) scores than patients without a prosthesis. Although this paper suggests a relationship between dental factors and the genesis of oral squamous cell malignancies, a larger prospective study would be required to achieve definitive data. Patients at risk should be followed carefully for the development of chronic irritation from teeth and appliances.

Oral status and prosthetic factors related to residual ridge resorption in elderly subjects

Our earlier studies on edentulous elderly subjects have shown associations of severe resorption in the mandibular residual ridge with female gender and systemic diseases. The aim of this study was to examine whether other factors also were related to residual ridge resorption (RRR). Among 177 edentulous elderly subjects effects on RRR were investigated with regard to history of edentulousness and denture-wearing, the condition of the dentures and soft tissues, dental status of the opposing jaw, and oral hygiene habits. No significant association was found between degree of resorption and duration of edentulousness in either the mandible or the madla. RRR was related to denture quality (P < 0.05); however, severe resorption was not. In the mavilla prekious use of removable partial dentures was a factor contributing to the resorption (odds ratio (OR), 2.4); flabby ridge was related to the severity of the resorption (OR, 2.4). This study showed local factors related to RRR more often in the maxilla than in the mandible, thus suggesting that severe resorption in the mandible is influenced more by systemic factors than by those investigated in this study.

Patient factors in appreciation of complete dentures

A re-examination of patients who wear complete dentures was performed 1 to 4 years after completion of prosthetic treatment in order to investigate the relationships between appreciation of the dentures and personal, social, anatomical, and prosthetic factors. The examination was comprised of medical, social, and clinical studies.

Some clinical factors related to rate of resorption of residual ridges

Bone resorption of residual ridges is common. The rate of resorption varies among different individuals and within the same individual at different times. Factors related to the rate of resorption are divided into anatomic, metabolic, functional, and prosthetic factors. Anatomic factors include the size, shape, and density of ridges, the thickness and character of the mucosal covering, the ridge relationships, and the number and depth of sockets. Metabolic factors include all of the multiple nutritional, hormonal, and other metabolic factors which influence the relative cellular activity of the bone-forming cells (osteoblasts) and the bone-resorbing cells (osteoclasts). Age, sex, and general health are inadequate to describe the bone factor but do give some clinical clues. Functional factors include the frequency, intensity, duration, and direction of forces applied to bone which are translated into cellular activity, resulting in either bone formation or bone resorption, depending on the patient's individual resistance to these forces. Prosthetic factors include the myriad of techniques, materials, concepts, principles, and practices which are incorporated into the prostheses. Although the various factors can be divided into these four groups for academic purposes, they are all interrelated, and any one factor may be evaluated only if we place it in its proper perspective to all factors. Since bone resorption depends on the response of living cells to force, the more basic sciences concerned with the physiology and pathology of cells are understood, the more educated will be our clinical judgment.

A cephalometric study of the clinical rest position of the mandible: Part II. The variability in the rate of bone loss following the removal of occlusal contacts

1. Balance between antagonistic muscles can occur at an infinite variety of muscle lengths and tones within certain physiologic limits because of the complex, dynamic character of the neuromuscular system. 2. Certain pathologic states of muscle are recognized clinically: stretch-weakness, shortness, contracture, spasm, hyper-tenseness, fatigue. 3. The ability of a patient to regain the lost vertical dimension with dentures will depend to a large degree on: (a) the amount of lengthening and stretch-weakness of the opening muscles, (b) the amount of shortness and tightness of the closing muscles, (c) the duration and permanence of these changes, (d) the amount of superimposed hyper-tenseness, (e) the degree of coordination and the ability to learn. 4. Of 32 patients studied cephalometrically after the insertion of dentures, 28 showed measurable bone resorption over intervals varying from 5 to 46 months, each patient varying to a different degree. 5. If these 32 patients are divided arbitrarily into those given an adequate interocclusal clearance and those not given an adequate interocclusal clearance, some with rapid rates of resorption and some with little or no resorption will be found in each group. The rate of bone loss appears to be more characteristic of the individual than of the group. 6. Analysis of the data suggests that there are many factors influencing the rate of resorption of edentulous ridge, including anatomic, functional, metabolic, and prosthetic factors, and that dependence on a single factor in the establishment of the occlusal vertical dimension is unsafe.