Functional aspects of treatment with implant-supported single crowns: a quality control study in subjects with tooth agenesis

Prognosis of Single Implant-Supported Prosthesis in Patients With Primary Sjögren's Syndrome: A Five-Year Prospective Clinical Study

BACKGROUND

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease characterized by hyposalivation. Currently, there is limited evidence for the prognosis of dental implant treatment in Sjögren's syndrome.

AIM/HYPOTHESIS

We hypothesized comparable clinical outcomes of implant-supported restorations in pSS-patients and control subjects, and improvement in oral health-related quality of life 5 years after restoration.

MATERIAL AND METHODS

Patients with pSS and matched (age, gender, and tooth region) control group were recruited between June 2016 and March 2020. The clinical and radiological examination were performed, and patient-reported oral health impact profile (OHIP-49) questionnaire was used 2 months (baseline), 1, 3, and 5 years after prosthetic treatment.

RESULTS

We included 23 patients with pSS and 24 matched control subjects (all women, mean age: 57.1 years). The overall DMFT (decayed-missed-filled-tooth) was significantly higher (p = 0.008), symptoms of dry mouth were more severe (p = 0.001), and unstimulated and chewing-stimulated saliva flow rates were significantly lower (p < 0.001) in pSS than in control group. All implants survived with no implant mobility. At implant sites, the plaque index and probing depths did not differ (p = 0.301 and 0.446, respectively), but the gingival index was significantly higher (p = 0.003) in pSS than control group. The mean marginal bone loss, prosthetic complications, and clinician-reported aesthetic outcomes were similar in both groups after 5 years. The OHIP scores were significantly higher in the pSS than control group (p < 0.001) but reduced significantly in both groups (p = 0.026).

CONCLUSION

Replacement of missing single teeth with dental implants was successful in patients with pSS 5 years after restoration.

SURVIVAL RATE OF IMPLANT-SUPPORTED, SINGLE-TOOTH RESTORATIONS BASED ON ZIRCONIA OR METAL ABUTMENT IN PATIENTS WITH TOOTH AGENESIS: A 5-YEARS PROSPECTIVE CLINICAL STUDY

OBJECTIVES

The primary aim was to investigate survival rate of zirconia versus metal abutments, and the secondary aim was clinical outcomes of all-ceramic versus metal-ceramic crowns on single-tooth implants.

METHODS

Patients with tooth-agenesis participated to previously published prospective clinical study with 3-year follow-up were recalled after 5 years. Biological variables included survival and success rate of implants, marginal bone level, modified Plaque and Sulcus Bleeding Index and biological complications. Technical variables included restoration survival rate, marginal adaptation and technical complications. The aesthetic outcome of crowns and peri-implant mucosa in addition to patient-reported outcome were recorded. Descriptive analysis, linear mixed model for quantitative data, or generalized linear mixed model for ordinal categorical data were applied; significance was set to 0.05.

RESULTS

Fifty-three patients (mean age: 32.4 years), with 89 implants participated to the 5-years examination. The implants supported 50 zirconia abutments with 50 all-ceramic (AC) crown and 39 metal abutments with 29 metal-ceramic (MC) and 10 AC crowns. The Implant and restoration survival rate was 100% and 96%, respectively. No clinically relevant biological difference between implants supporting metal or zirconia abutments was registered. The technical complications were veneering fracture of AC-crowns (n = 3), crown loosening of MC-crowns (n = 4) and one abutment screw loosening (MC-crown on metal abutment). MC-crowns had significantly better marginal adaptation than AC-crowns (p = .01). AC-crowns had significantly better color and morphology than MC-crowns (p = .01).

CONCLUSIONS

Zirconia-based single-tooth restorations are reliable alternative materials to metal-based restorations with favorable biological and aesthetic outcome, and few technical complications.

Unveiling the Influence of the Curve of Spee on Bite Force and Chewing Ability: A Comparative Study

Aim

To investigate the impact of the curve of Spee (CS) accentuation on bite force, chewing ability, and additionally, other factors that influence chewing ability and bite force such as restorations, caries, gender, habits, and TMJ problems.

Materials and Methods

231 participants (118 male and 113 female, mean age = ±27.96 years) were recruited for this cross-section study. Participants completed a data collection sheet in which age, gender, Angle's classification of malocclusion, overjet, overbite, TMJ problems, habits, restorations, and caries experience were recorded. Two examiners made a lower impression, chewing ability test and measured the bite force for each participant. Measurement of the CS was obtained digitally from the poured dental cast, and the categorization was as follows: flat (<1 mm), normal (1-2 mm), or deep (>2 mm).

Results

The mean maximum bite force (MBF) was 468.722 N for participants with flat CS, 389.822 N for normal CS, 647.08 N for deep CS, and 384.667 N for reverse CS. The average MBF was higher for participants with deep CS (p < 0.05). MBF force was higher in males. However, BMI was not significantly related to MBF values. Participants with normal and flat CS have comparable chewing capacity (p > 0.05). Also, a significant difference in bite force and chewing ability was found between the three categories of CS (p < 0.05).

Conclusion

Bite force variations across various CS types were linked to gender and habits. Chewing ability showed no differences concerning gender, habits, TMJ problems, caries, or restorations, emphasizing CS's significant impact on bite force while showcasing the unchanged nature of chewing ability amidst diverse factors.

Application in the analysis of the occlusal force of free-end missing tooth implant restoration with T-SCAN III

Introduction: The occlusal force of the teeth in the dental arch and the remaining adjacent natural teeth will change after implant restoration with a free-end missing tooth. This study intends to use the T-SCAN III scanner to collect dynamic quantitative data before and after the restoration of free-end implants and to explore the application of the T-SCAN III in redistributing the occlusal force of free-end implants.

Methods: In this study, 24 patients with free-end implant restoration were selected, and their occlusion was tested before, immediately after, and 3 months after implant restoration.

Results: In all 24 cases, the bite force of the first natural tooth adjacent to the implanted tooth after restoration changed from 19.12% ± 9.48%–12.93% ± 11.47% (p &lt; 0.01). For additional data analysis, all cases were further subdivided by single implant and fixed bridge restorations. In 17 cases, there was a successful follow-up after 3 months. The percentage of the total bite force of dental arch with implant increased from 41.92% ± 10.78%–53.06% ± 10.71% (p &lt; 0.01).

Discussion: This study shows that the free-end implant restoration protects the remaining natural teeth, and the patient’s missing dental arch bite force improves within 3 months of implant restoration.

A five-year randomised controlled trial comparing zirconia-based versus metal-based implant-supported single-tooth restorations in the premolar region

OBJECTIVES

To compare 5-year biological, technical, aesthetic, and patient-reported outcomes of single-tooth implant-supported all-ceramic versus metal-ceramic restorations.

MATERIALS AND METHODS

Thirty patients with 63 premolar agenesis participated in the 5-year follow-up. The prosthetic treatment on single-tooth implants were randomly assigned to all-ceramic crowns on zirconia abutments (AC=31) or metal-ceramic crowns on metal abutments (MC=32). All patients were recalled to clinical examinations at baseline, 1, 3, and 5 years after prosthetic treatments. Biological, technical, and aesthetic outcomes including complications, were clinically and radiographically registered. The patient-reported outcomes were recorded using OHIP-49 questionnaire before treatment and at each follow-up examination.

RESULTS

At 5-year examination, the survival rate was 100% for implants and 100 % for AC and 97% for MC crowns and abutments. The marginal bone loss after 5-years was minor and not significantly different (p= 0.056) between AC (mean: 0.3, SD: 1.1) and MC restorations (mean: -0.1, SD: 0.4). The success rate of the implants based on marginal bone loss was 77.4% for AC- and 93.7% for MC-restorations. The marginal adaptation was significantly better for MC than for AC restorations (p=0.025). The aesthetic outcomes and patient-reported outcomes between AC and MC restorations were not significantly different.

CONCLUSIONS

The biological, aesthetic and patient-reported outcomes for implant-supported AC and MC restorations were successful and with no significant difference after 5-years. The marginal adaptation of the MC crowns cemented on titanium abutments showed significantly better fit than restorations based on zirconia crowns cemented on zirconia abutments.

Comparison of the prognosis of the remaining teeth between implant-supported fixed prostheses and removable partial dentures in partially edentulous patients: A retrospective study

BACKGROUND

There have been several reports about the prognosis of teeth adjacent to edentulous spaces for implant-supported fixed prostheses (ISFPs) and removable partial dentures (RPDs). However, there are few reports about the prognosis of the other remaining teeth comparing ISFPs with RPDs.

PURPOSE

The aim of this study was to evaluate and compare the prognosis of the remaining teeth for ISFPs and RPDs in terms of survival and complication-free rates.

METHODS

Subjects were partially edentulous patients with ISFPs or RPDs inserted in 2003-2016. Teeth adjacent to edentulous spaces (A-teeth), teeth not adjacent to edentulous spaces (R-teeth), and teeth opposing edentulous spaces (O-teeth) were investigated. The endpoints were tooth extraction and complications. A multivariate cox regression model was used to estimate the risk factors for survival of the investigated teeth.

RESULTS

A total of 233 (ISFP: 89, RPD: 144) patients were included in the statistical analyses. An IFSP prosthesis, when compared to an RPD prosthesis did not significantly decrease the tooth loss rate for A-teeth (hazard ratio [HR]: 0.76; 95% confidence interval [CI]: 0.30-1.92), for R-teeth (HR: 0.54; 95% CI: 0.28-1.05), or for O-teeth (HR: 0.45; 95% CI: 0.10-2.09).

CONCLUSIONS

In partially edentulous spaces, the difference between ISFPs and RPDs does not affect the prognosis of teeth adjacent to edentulous spaces, teeth not adjacent to edentulous spaces, and teeth opposing edentulous spaces. Namely, our findings suggest that it depends largely on the tooth type, jaw, endodontic therapy performed, not on the type of prostheses.

Hypodontia and its impact on a young person's quality of life, esthetics, and self-esteem

INTRODUCTION

The impact of hypodontia on quality of life is a relatively unexplored area. The limited research shows that the issues of importance for people with hypodontia can vary from those of patients undergoing routine orthodontic treatment. This research aimed to use generic and condition-specific scales to evaluate the impact of hypodontia on a young person's oral health-related quality of life, self-esteem, and aesthetics.

METHODS

This prospective cross-sectional hospital-based study recruited 97 participants with hypodontia, aged 11-18 years. The following questionnaires were completed before the start of any planned treatment: child perception questionnaire, Bristol condition-specific questionnaire for hypodontia, child health questionnaire, and Oral Aesthetic Subjective Impact Scale. A priori sample size calculation determined a minimum of 65 participants were required, at the 5% level of significance, and with a power of 80%. The number was inflated to allow for dropouts/loss to follow-up by 30%.

RESULTS

A total of 323 teeth were missing; 58 subjects (36 female) showed mild (2 absent teeth), and 39 subjects (25 female) showed moderate to severe (>2 absent teeth) hypodontia. Forty-one (42%) patients were missing anterior teeth, with absent maxillary lateral incisors predominating. Significant differences were found for the overall child perception questionnaire (P = 0.01), emotional (P = 0.005), and social (P = 0.003) well-being; scores were highest in the moderate to severe hypodontia group, revealing the greatest negative impact. Similarly, overall Bristol condition-specific questionnaire for hypodontia (P <0.001), treatment (P = 0.001), appearance (P = 0.013), and other people's reaction (P <0.001) domains were all significant, with the moderate to severe group reporting higher levels of negative impact. No significant differences were observed in self-esteem or esthetics.

CONCLUSIONS

Hypodontia in young people appear to have a negative psychosocial impact, both in terms of its presentation and planned care.

Gender differences in masticatory function in elderly adults with natural dentition

The purpose of this study was to clarify the presence or absence of gender differences in masticatory function in elderly adults with completely natural dentition. Fifty-six elderly adults aged 65 years and older (elderly group) and 60 young adults in their 20-40 s (young group) with natural dentition participated in this study. The maximum occlusal force on the habitual chewing side was measured using dental prescale. Next, the amount of glucose extraction when subjects chewed a gummy jelly on their habitual chewing side for 20 s was measured. The maximum occlusal force and masticatory performance in the elderly and young groups were compared between males and females. The relationship between the maximum occlusal force and masticatory performance was also investigated. The maximum occlusal force in the elderly and young groups was larger in males than in females, and the difference was significant. The amount of glucose extraction in the elderly and young groups was higher in males than in females, and the difference was significant. Regarding the relationship between the maximum occlusal force and the amount of glucose extraction, there was a significant positive correlation. These results suggest that there are gender differences in the masticatory function of the elderly adults with completely natural dentition, and these differences need to be noted in the evaluation of masticatory function.

Does implantoplasty affect the failure strength of narrow and regular diameter implants? A laboratory study

Objective

To assess whether the impact of implantoplasty (IP) on the maximum implant failure strength depends on implant type/design, diameter, or material.

Methods

Fourteen implants each of different type/design [bone (BL) and tissue level (TL)], diameter [narrow (3.3 mm) and regular (4.1 mm)], and material [titanium grade IV (Ti) and titanium-zirconium alloy (TiZr)] of one company were used. Half of the implants were subjected to IP in a computerized torn. All implants were subjected to dynamic loading prior to loading until failure to simulate regular mastication. Multiple linear regression analyses were performed with maximum implant failure strength as dependent variable and IP, implant type/design, diameter, and material as predictors.

Results

Implants subjected to IP and TL implants showed statistically significant reduced implant failure strength irrespective of the diameter compared with implants without IP and BL implants, respectively. Implant material had a significant impact for TL implants and for regular diameter implants, with TiZr being stronger than Ti. During dynamic loading, 1 narrow Ti TL implant without IP, 4 narrow Ti TL implants subjected to IP, and 1 narrow TiZr TL implant subjected to IP were fractured.

Conclusion

IP significantly reduced the maximum implant failure strength, irrespective implant type/design, diameter, or material, but the maximum implant failure strength of regular diameter implants and of narrow BL implants remained high.

Clinical Relevance

IP seems to have no clinically relevant impact on the majority of cases, except from those of single narrow Ti TL implants, which may have an increased risk for mechanical complications. This should be considered for peri-implantitis treatment planning (e.g., communication of potential complications to the patient), but also in the planning of implant installation (e.g., choosing TiZr instead of Ti for narrow implants).

The impact of oro-facial appearance on oral health-related quality of life: A systematic review

Esthetics in the oro-facial region are important for perceived oral health and a common reason for treatment of discoloured, missing or crowded teeth. As one of the fundamental bricks of a patient's oral health, changes in the domain of oro-facial esthetics resides within the oral health-related quality of life (OHRQoL) of an individual. Four main dimensions, oral function, oro-facial pain, oro-facial appearance and psychosocial impact, are suggested to cover the concept of OHRQoL. The aim of this systematic review was to map the impact from oral conditions with principal impact on the oro-facial appearance dimension of OHRQoL (PROSPERO: CRD42017064033). Publications were included if they reported Oral Health Impact Profile (OHIP) mean or median domain scores for patients with esthetic treatment need relating to tooth wear, orthodontics, orthognathic surgery, frontal tooth loss or tooth whitening. A search in PubMed (Medline), EMBASE, Cochrane, CINAHL and PsycINFO 8 June 2017 and updated 14 January 2019, identified 2,104 abstracts. After screening of abstracts, 1607 articles were reviewed in full text and 33 articles included. These 33 articles reported OHIP-data for 9409 patients grouped in 63 patient populations. Median oro-facial appearance impact scores on a standardised 0-8 scale, for populations with treatment need relating to tooth wear, orthodontics, orthognathic surgery, frontal tooth loss and tooth whitening, ranged from 0.13 for tooth wear to 3.04 for tooth whitening populations. In conclusion, a moderate impact for the oro-facial appearance dimension of OHRQoL was found in patients with different conditions with esthetically related treatment need.

Functional oral health-related quality of life impact: A systematic review in populations with tooth loss

Patients perceive the impact of oral disorder in four major areas, the dimensions of oral health-related quality life (OHRQoL) Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact. The functional aspect is essential given the need of chewing, biting, speech and swallowing. The objective of this study was to identify OHRQoL information for dental subjects with functional oral health problems. In a systematic review, distinct and clinically relevant groups of dental subject samples, in this study called "population groups," with such functional OHRQoL information based on the Oral Health Impact Profile (OHIP) were identified (PROSPERO registration: CRD42017064033). The search strategy was "Oral Health Impact Profile" or OHIP. Searches were conducted in the PubMed interface of the Medline database, EMBASE, Cochrane, CINAHL and PsyINFO on 8 June 2017 and updated on 14 January 2019. Published OHIP domain data of different versions were recalculated into OHIP-14`s Physical Disability domain score, characterising the subject's Oral Function impact. 3,653 potentially abstracts were screened. We identified 78 publications reporting dimensional information on 154 subject samples with 52 populations. A typical mean functional impact for partially dentate subjects was 1.6 units on a 0 to 8 unit metric, while for edentate subjects, the mean functional impact was 2.6 units. The functional impact score ranged from 0 to 7.9 units with 50% of the patient samples located between 0.8 and 2.6 units. For the first time, we provide normalised and therefore comparable metric information about the functional OHRQoL impact for a substantial number of functional oral conditions.

Effect of implant therapy on oral health-related quality of life (OHIP-49), health status (SF-36), and satisfaction of patients with several agenetic teeth: Prospective cohort study

Background

Effect of fixed prosthodontics on patients with several agenetic teeth is not well understood.

Purpose

To assess the effect of implant‐based fixed prosthodontics on oral health‐related quality of life (OHRQoL), general health status, and satisfaction regarding dental appearance, ability to chew and speech in patients with several agenetic teeth.

Materials and Methods

For this prospective cohort study, all patients (≥18 years) with several agenetic teeth who were scheduled for treatment with fixed dental implants between September 2013 and July 2015 at our department were approached. Participants received a set of questionnaires before and 1 year after implant placement to assess OHRQoL (OHIP‐NL49), general health status (SF‐36), and satisfaction regarding dental appearance, ability to chew and speech.

Results

About 25 out of 31 eligible patients (10 male, 15 female; median age: 20 [19;23] years; agenetic teeth: 7 [5;10]) were willing to participate. Pre‐ and post‐treatment OHIP‐NL49 sum‐scores were 38 [28;56] and 17 [7;29], respectively (P < .001). Scores of all OHIP‐NL49 subdomains decreased tool, representing an improved OHRQoL (P < .05) as well as that satisfaction regarding dental appearance, ability to chew and speech increased (P < .001). General health status did not change with implant treatment (P > .05).

Conclusions

Treatment with implant‐based fixed prosthodontics improves OHRQoL and satisfaction with dental appearance, ability to chew and speech, while not affecting general health status.

Identification and appraisal of outcome measures used to evaluate hypodontia care: A systematic review

INTRODUCTION

Identification and appraisal of the outcome measures that have been used to evaluate hypodontia treatment and deliver services are essential for improving care. A lack of alignment between outcomes and patient values can limit the scope for patient-centered care. Our objectives were to identify and appraise the outcomes selected to evaluate hypodontia care.

METHODS

Data sources included 10 electronic databases and grey literature, searched using terms for hypodontia and its treatment methods. Study eligibility included mixed study designs to ensure comprehensive identification of outcomes, excluding case reports and case series with fewer than 10 participants and nonsystematic reviews. Participants and interventions involved people with hypodontia receiving any dental treatment to manage their hypodontia. Simulated treatment, purely laboratory-based interventions, and future treatments still in development were excluded. Research outcomes were identified and synthesised into 4 categories: clinical indicators, and patient-reported, clinician-reported, and lay-reported outcomes. No synthesis of efficacy data was planned, and consequently no methodologic quality appraisal of the studies was undertaken.

RESULTS

The search identified 497 abstracts, from which 106 eligible articles were retrieved in full. Fifty-six studies and 8 quality-improvement reports were included. Clinical indicators were reported in 49 studies (88%) including appearance, function, dental health, treatment longevity, treatment success and service delivery. Patient-reported outcomes were given in 22 studies (39%) including oral health-related quality of life, appearance, function, symptoms of temporomandibular dysfunction, and patient experience. Clinician-reported outcomes were limited to appearance. Variability was seen in the tools used for measuring outcomes.

CONCLUSIONS

There is a lack of rationale and consistency in the selection of outcome measures used to evaluate hypodontia care. Outcomes are largely clinician and researcher-driven with little evidence of their relevance to patients. There was a paucity of outcomes measuring access to care, quality of care, and cost. Evidence from hypodontia research is clinician-focused and likely to have limited value to support patients during decision making. Attempts to synthesise the evidence base for translation into practice will be challenging. There is a need for a core outcomes set with a patient-centric approach to drive improvements in health services.

Evaluation of the Alteration of Occlusal Distribution in Unilateral Free-End and Intermediate Missing Cases

The present study aimed to evaluate the effect of implant prostheses on the occlusal force and area as well as the distribution of occlusal loading in unilateral free-end and intermediate missing cases. Fourteen healthy subjects (7 free-end missing cases in the first and second molars and 7 intermediate missing cases in the first molar region) were included. Six months after the implant prosthesis was placed, an occlusal evaluation was performed with or without the implant superstructure by using Dental Prescale film and an occluder device. In free-end missing cases, the total occlusal force and area, implant-side occlusal force and area, and implant-side occlusal force and area of the residual natural teeth were significantly affected by the implant prostheses. In intermediate missing cases, the implant-side occlusal force of the residual natural teeth was significantly affected by the implant prostheses. In free-end missing cases, the proportions of implant-side occlusal force, non–implant-side occlusal force, and implant-side occlusal force of the residual natural teeth relative to the total occlusal force were significantly affected by the implant prostheses. In the intermediate missing cases, the proportion of the implant-side occlusal force of the residual natural teeth relative to the total occlusal force was significantly affected by the implant prostheses. The proportion of the occlusal area was also significantly affected. In free-end missing cases, implant prostheses significantly increased the occlusal force and area, which resulted in the proper occlusal distribution. In intermediate missing cases, an implant prosthesis may only improve the same-side occlusal loading of the natural teeth.

Occlusal rehabilitation in patients with congenitally missing teeth-dental implants, conventional prosthetics, tooth autotransplants, and preservation of deciduous teeth-a systematic review

Background

Implant patients with congenitally missing teeth share some common charateristics and deserve special attention.

Methods

The PICO question was “In patients with congenitally missing teeth, does an early occlusal rehabilitation with dental implants in comparison to tooth autotransplants, conventional prosthetics on teeth or preservation of deciduous teeth have better general outcomes in terms of survival, success and better patient centered outcomes in terms of quality of life, self-esteem, satisfaction, chewing function?”

After electronic database search, a total of 63 relevant studies were eligible, of which 42 qualified for numerical data synthesis, 26 being retrospective studies. A data synthesis was performed by weighted means for survival/success/annual failure rates.

Results

The mean survival of implants was 95.3 % (prosthesis survival 97.8 %), autotransplants 94.4 %, deciduous teeth 89.6 %, and conventional prostheses 60.2 %. The implant survival in children, adolescents, and adults was 72.4, 93.0, and 97.4 %. Annual failure rates of implants 3.317 %, autotransplants 1.061 %, deciduous teeth 0.908 %, and conventional prostheses 5.144 % indicated better results for natural teeth and more maintenance needs for the both prosthetic treatments. The mean OHIP score was 27.8 at baseline and a mean improvement of 14.9 score points was reported after implant prosthetics. The mean satisfaction rates were 93.4 (implants), 76.6 (conventional prostheses), 72.0 (autotransplants), and 65.5 % (orthodontic space closure).

Conclusions

In synopsis of general and patient-centered outcomes, implants yielded the best results, however, not in children <13 years. Autotransplants and deciduous teeth had low annual failure rates and are appropriate treatments in children and adolescents at low costs. Conventional prosthetics had lower survival/success rates than the other options. Due to heterogeneity and low number of studies, patient-reported outcomes in this review have to be interpreted with caution.

Assessment of masticatory performance by means of a color-changeable chewing gum

PURPOSE

Previous research determined the relevance of masticatory performance with regard to nutritional status, cognitive functions, or stress management. In addition, the measurement of masticatory efficiency contributes to the evaluation of therapeutic successes within the stomatognathic system. However, the question remains unanswered as to what extent modern techniques are able to reproduce the subtle differences in masticatory efficiency within various patient groups. The purpose of this review is to provide an extensive summary of the evaluation of masticatory performance by means of a color-changeable chewing gum with regard to its clinical relevance and applicability.

STUDY SELECTION

A general overview describing the various methods available for this task has already been published. This review focuses in depth on the research findings available on the technique of measuring masticatory performance by means of color-changeable chewing gum. Described are the mechanism and the differentiability of the color change and methods to evaluate the color changes. Subsequently, research on masticatory performance is conducted with regard to patient age groups, the impact of general diseases and the effect of prosthetic and surgical treatment.

RESULTS

The studies indicate that color-changeable chewing gum is a valid and reliable method for the evaluation of masticatory function.

CONCLUSION

Apart from other methods, in clinical practice this technique can enhance dental diagnostics as well as the assessment of therapy outcomes.

Mastication improvement after partial implant-supported prosthesis use

Partially edentulous patients may be rehabilitated by the placement of removable dental prostheses, implant-supported removable dental prostheses, or partial implant fixed dental prostheses. However, it is unclear the impact of each prosthesis type over the masticatory aspects, which represents the objective of this paired clinical trial. Twelve patients sequentially received and used each of these 3 prosthesis types for 2 months, after which maximum bite force was assessed by a strain sensor and food comminution index was determined with the sieving method. Masseter and temporal muscle thicknesses during rest and maximal clenching were also evaluated by ultrasonography. Each maxillary arch received a new complete denture that was used throughout the study. Data were analyzed by analysis of variance for repeated measures, followed by the Tukey test (p < .05). Maximum bite force and food comminution index increased (p < .0001) after implant-supported dental prosthesis and implant fixed dental prosthesis use, with the higher improvement found after the latter's use. Regardless of implant-retained prosthesis type, masseter muscle thickness during maximal clenching also increased (p < .05) after implant insertion. Partial implant-supported prostheses significantly improved masseter muscle thickness and mastication, and the magnitude of this effect was related to prosthesis type.

Fracture mode during cyclic loading of implant-supported single-tooth restorations

STATEMENT OF PROBLEM

Fracture of veneering ceramics in zirconia-based restorations has frequently been reported. Investigation of the fracture mode of implant-supported ceramic restorations by using clinically relevant laboratory protocols is needed.

PURPOSE

This study compared the mode of fracture and number of cyclic loads until veneering fracture when ceramic and metal ceramic restorations with different veneering ceramics were supported by implants.

MATERIAL AND METHODS

Thirty-two implant-supported single-tooth restorations were fabricated. The test group was composed of 16 ceramic restorations of zirconia abutment-retained crowns with zirconia copings veneered with glass-ceramics (n=8) and feldspathic ceramics (n=8). The control group was composed of 16 metal ceramic restorations of titanium abutment-retained crowns with gold alloy copings veneered with glass (n=8) and feldspathic ceramics (n=8). The palatal surfaces of the crowns were exposed to cyclic loading of 800 N with a frequency of 2 Hz, which continued to 4.2 million cycles or until fracture of the copings, abutments, or implants. The number of cycles and the fracture modes were recorded. The fracture modes were analyzed by descriptive analysis and the Mann-Whitney test (α=.05). The differences in loading cycles until veneering fracture were estimated with the Cox proportional hazards analysis.

RESULTS

Veneering fracture was the most frequently observed fracture mode. The severity of fractures was significantly more in ceramic restorations than in metal ceramic restorations. Significantly more loading cycles until veneering fracture were estimated with metal ceramic restorations veneered with glass-ceramics than with other restorations.

CONCLUSIONS

The metal ceramic restorations demonstrated fewer and less severe fractures and resisted more cyclic loads than the ceramic restorations, particularly when the metal ceramic crowns were veneered with glass-ceramics.

Oral health-related quality-of-life in patients to be treated with fixed or removable partial dental prostheses

OBJECTIVES

The aims of this study were to measure and describe the Oral Health-Related Quality-of-Life (OHRQoL) in a population about to receive removable dental prostheses (RDP) or fixed dental prostheses (FDP).

MATERIALS AND METHODS

The Oral Health Impact Profile 49 (OHIP-49) was completed by 410 patients about to receive treatment with either RDP or FDP. Objective variables were: gender, age, number of teeth, type of replacement planned (FDP/RDP) and location (one jaw or both) and zone (aesthetic/masticatory/both) of missing teeth to be replaced.

RESULTS

Women had a worse OHRQoL than men in the RDP group. Higher age was significantly correlated with a better OHRQoL independent of treatment modality. Participants about to receive FDP in one jaw in the masticatory zone only had a better OHRQoL than RDP participants in the same group. The most frequently reported problems in all groups concerned functional limitations, discomfort and physical disabilities. Little variance in reported items was seen between the sub-groups and social handicap was not frequently reported.

CONCLUSIONS

The difference in OHRQoL between participants about to receive RDP and FDP was limited. The most frequently reported problems concerned functional limitations, discomfort and physical disabilities. Social handicap was not frequently reported.

Oral health-related quality of life and dental implants — preliminary study

Oral health-related quality of life (OHRQoL) is multifaceted and involves many factors. One of them is the use of dental implants. It was the aim of our study to assess whether implant therapy might improve OHRQoL. We consulted patients with at least one Astra Tech implant. Each patient completed oral health questionnaires, which were then statistically evaluated using the Wilcoxon signed-ranks test and Analysis of Covariance from a functional and aesthetic point of view. Differential response on individual scales was assessed using multivariate approach. All twelve marginal Wilcoxon tests showed an overall improvement in OHQoL (α = 0.05). On the aesthetic scale, OHRQoL was found to be associated with marital status, aesthetic reasons for undergoing surgery and number of front teeth replaced by implants. On the functional scale, three covariates were statistically significantly and appeared to have affected the levels of OHRQoL. The most significant explanatory effect was observed for the number of front teeth replaced via implantation, followed by the presence of chewing problems. Marital status was also found to have significantly affected the OHRQoL functional scale. Significant implant-related improvements in both scales were observed in patients with at least one implant in the front dental area.