The future of complete dentures in oral rehabilitation. A critical review

Masticatory performance of different impression methods for complete denture fabrication: A randomized controlled trial

OBJECTIVES

To compare the effect of conventional complete dentures fabricated using two different impression methods on masticatory performance and factors relating to masticatory performance in a randomized controlled trial.

METHODS

A crossover randomized controlled trial was performed with edentulous patients requiring maxillomandibular complete dentures. Mandibular complete dentures were fabricated using two different methods. The conventional method (C) used a custom tray border molded with an impression compound and a silicone. The simplified method (S) used a stock tray and an alginate. Participants were randomly divided into the two groups. In the C-S group, the conventional method was used first, followed by the simplified method; the order was reversed in the SC group. Adjustments were performed four times. The wash out period was 1 month. Masticatory performance as assessed by the mixing of a color-changeable chewing gum (mixing ability). Maximum occlusal force, occlusal contact area, and perceived chewing ability were assessed for each group.

RESULTS

Twenty-seven patients underwent randomization and 24 participants completed the trial. With regard to occlusal contact area, the conventional method showed significantly larger occlusal contact area than the simplified method. No significant differences were observed between the two methods regarding mixing ability, maximum occlusal force, and perceived chewing ability.

CONCLUSIONS

This study showed that complete dentures fabricated with the conventional method had a significantly larger occlusal contact area than those made using the simplified method.

CLINICAL SIGNIFICANCE

Complete dentures fabricated with the conventional method, comprising a preliminary impression using alginate in a stock tray followed by a final impression using silicone impression material in a border molded custom tray, resulted in fewer post-insertion adjustments than the simplified method, potentially contributing to earlier stability of new dentures.

Teaching Complete Denture Procedures to Dental Students by Conventional or Simplified Methods: A Randomized Clinical Trial

With populations aging around the world, the need for complete dentures is likely to increase in Brazil and other developing countries, as well among low-income populations globally, making the teaching of cost-efficient techniques to dental students essential. The aim of this study was to evaluate the effectiveness of complete dentures fabricated by the simplified method in comparison to the conventional method regarding patients' oral health-related quality of life (OHRQoL) and satisfaction, dentures' functional quality, and masticatory performance of patients who were rehabilitated by dental students. From February 2016 to April 2017, final-year dental students at the Federal University of Alfenas, Brazil, were instructed to fabricate new complete dentures for 36 edentulous patients, who were randomly divided into two groups according to denture manufacturing method: simplified method or conventional method. Patients' OHRQoL and satisfaction and the prostheses quality were evaluated at one, three, and six months. Masticatory performance was evaluated at three months. The results showed there was no significant difference between the two methods regarding OHRQoL, patient satisfaction, prostheses quality, or masticatory performance (p>0.05). All aspects evaluated also remained constant for the same group (simplified method or conventional method) in all periods of evaluation (p>0.05). The study concluded that the simplified method for complete denture fabrication was able to produce protheses with functional quality and patient satisfaction comparable to those produced with the conventional method, even when made by dental students.

Reinforcement of PMMA Denture Base Material with a Mixture of ZrO2 Nanoparticles and Glass Fibers

This study is aimed at evaluating the hybrid reinforcement effects of zirconium oxide nanoparticles (nano-ZrO₂) and glass fibers (GFs) at different ratios on the flexural and impact strengths of a polymethylmethacrylate (PMMA) denture base. A total of 160 specimens were fabricated from heat-polymerized acrylic resins using the water bath technique. For the control group, the specimens did not receive any additions; for the test group, different concentrations of nano-ZrO₂/GFs at 5% of the PMMA polymer were added. The concentrations of nano-ZrO₂/GFs were as follows: 5%–0%, 4%–1%, 3%–2%, 2.5%–2.5%, 2%–3%, 1%–4%, and 0%–5%. The flexural strength was measured using the three-point bending test. The impact strength was measured using the Charpy impact test. Results were tabulated and analyzed using one-way analysis of variance (ANOVA) and the Tukey–Kramer multiple comparison test (p ≤ 0.05). The flexural and impact strengths of PMMA-nano-ZrO₂ + GF composites were significantly improved when compared with those of pure PMMA (p < 0.05). The maximum flexural strength (94.05 ± 6.95 MPa) and impact strength (3.89 ± 0.46 kJ/m²) were obtained with PMMA (2.5%)/nano-ZrO₂ + 2.5% GF mixtures and could be used for removable prosthesis fabrication.

Success of Complete Denture Treatment, Detailed Investigation of Construction Protocols, Occlusal Schemes and Evaluation Questionnaires

Background/Aim: The successful outcome of conventional complete denture treatment can be defined with the use of both subjective and objective criteria. Denture satisfaction determinants may include denture quality, oral tissue condition, patient-dentist relationship, patient’s attitude toward dentures, patient’s personality and socioeconomic factors. Purpose: The aim of the current review was to identify and analyze the different construction protocols and occlusal schemes that contribute to the success of complete denture rehabilitation through the use of evaluation questionnaires.

Material and Methods: A comprehensive literature search was performed through electronic databases (MEDLINE via PubMed) using the appropriate key words (complete denture construction, complete denture fabrication, complete denture occlusion and complete denture occlusal scheme). The related to the subject scientific papers were selected and evaluated for eligibility utilizing a predefined review process (English, full text articles, published from January 2000 up to April 2017).

Results: None of the analyzed studies identified significant differences between dentures constructed with simplified, CAD/CAM and traditional protocols in terms of general satisfaction and Oral Health Related Quality of Life scales. The same condition applied to the studies which compared complete dentures with bilateral balanced, lingualized, monoplane and canine guided occlusion.

Conclusions: Current scientific evidence suggested that patients could adapt comfortably to any type of bilateral balanced occlusal scheme and to complete dentures been fabricated with all types of complete denture construction protocol. Disease-specific questionnaires could be considered valuable tools and should be used to assess the outcome of any treatment modality.

Influence of lower complete denture use on masseter muscles and masticatory function: A longitudinal study

BACKGROUND

Edentulism can reduce mastication, leading to changes in food pattern, with possible consequences to masticatory muscle thickness.

OBJECTIVES

This study verified masticatory function and oral perception in subjects who did not use lower CDs, and whether the insertion of new upper and lower CDs would improve such variables.

METHODS

Fifteen edentulous elderly who wore only the upper CD were selected and received new upper and lower CD. Volunteers were evaluated at baseline and after 1, 3 and 6 months of new prosthesis use. Masticatory performance (MP) was assessed by the sieving method (X₅₀ values). Masseter thickness (MT) was evaluated by ultrasonography. Oral sensorial ability (OSA) was assessed by oral stereognosis test and maximum tongue pressure (MTP) was verified by pressure sensors. Data were submitted to repeated measures ANOVA and Tukey-Kramer posthoc tests (α = 0.05). Correlation between OSA and MTP was verified by Person's correlation.

RESULTS

X₅₀ and MTP decreased (P < 0.05) after 1 month and remained stable (P > 0.05) for next assessments. After 3 months, MT in rest position was increased (P < 0.05), while during maximum voluntary contraction 1 month was enough to increase MT (P < 0.05). There were no differences for OSA (P > 0.05) and no correlation between OSA and MTP.

CONCLUSION

Masticatory performance and masseter thickness of elderly who did not use the lower dentures were improved after 2 months using new upper and lower CDs. However, new CDs in both dental arch decreased MTP. Brazilian Registry of Clinical Trials (ReBEC #RBR-37gdst).

Masticatory function of conventional complete denture wearers changing to 2-implant retained mandibular overdentures: clinical factor influences after 1year of function

PURPOSE

Evaluate how clinical factors related to conventional complete denture (CCD) wearers, can influence masticatory function (MF) of totally edentulous patients before and after one-year transitioning to implant-retained mandibular overdentures (IMO).

METHODS

Forty patients using CCD were rehabilitated with IMO and their MF was evaluated by: (i) ST_X50: theoretical aperture through which 50% of the weight of the particles would pass; (ii) STB: distribution homogeneity of the crushed particles. The clinical parameters analyzed were: atrophy, retention, stability, facial type, anteroposterior skeletal discrepancy, and type of loading. The statistical association was tested through crude and adjusted logistic regression.

RESULTS

IMO promoted improvements in the MF, irrespective of the clinical parameters. CCD wearers with poor retention had 86% less chance of achieving a good ST_X50. STB was associated with stability, facial type, and anteroposterior discrepancy. Subjects with poor mandibular CCD stability had a 76% lower chance of achieving a good test food homogenization, whereas brachyfacial individuals were 1.3 times more likely to have a good STB. Class II patients had an 89% lower chance of having a good homogenization of the particles as CCD users and after transition to IMO.

CONCLUSIONS

CCD users with poor retention achieved an inferior ST_X50. The STB performance can be compromised by poor stability or Class II characteristics, while brachyfacial individuals achieve better homogenezation of the food bolus. Although the transition to IMO improved the masticatory function, the anteroposterior discrepancy still maintained an association with STB, as Class II individuals still presented difficulties homogenizing food.

Incorporation of the microencapsulated antimicrobial agent phytoncide into denture base resin

BACKGROUND

This study aimed to fabricate a denture base resin (DBR) containing phytoncide microcapsules (PTMCs) and determine the mechanical properties of the resin and antifungal activity.

METHODS

Fifty-four heat-cured rectangular DBR specimens (64 × 10 × 3.3 ± 0.2 mm) containing nine concentrations of PTMC between 0 and 5% (wt/wt) were fabricated and subjected to a three-point bending test. A phytoncide release bioassay was developed using DBR containing 0% and 2.5% PTMCs (wt/wt) in a 24 well-plate assay with incubation of Porphyromonas gingivalis at 37 °C for 74 h. The antifungal activity of PTMCs against Candida albicans, in a pH 5.5 acidic environment was determined in a plate assay.

RESULTS

Flexural strength decreased with increasing PTMC concentration from 97.58 ± 4.79 MPa for the DBR alone to 53.66 ± 2.46 MPa for DBR containing 5.0% PTMC. No release of phytoncide from the PTMCs in the DBR was detected at pH 7.4. The PTMCs had a minimal inhibitory concentration of 2.6% (wt/vol) against C. albicans at pH 5.5.

CONCLUSIONS

PTMCs can be added to DBR 2.5% (wt/wt) without adversely affecting flexural strength. PTMCs released the antimicrobial agent at pH 5.5 at concentrations sufficient to inhibit the growth of the C. albicans.

Patient satisfaction with occlusal scheme of conventional complete dentures: A randomised clinical trial (Part II)

The occlusion of choice is a controversial topic in conventional complete denture (CCD) treatment. This study aimed to compare patient satisfaction with CCD with partially group-function occlusion (PGFO), fully bilateral balanced occlusion (FBBO), buccalised occlusion (BO), lingualised occlusion (LO) and the entire balanced group. Participants received new CCDs with PGFO. All steps of patient enrolment, denture fabrication, assessments during the follow-up period and data collection were carried out exactly the same as part 1 of this research project. All patients were recalled at 1 and 3 months after delivery for data collection using the shortened version of oral health impact profile for edentulous patients (OHIP-EDENT) questionnaire and 7 visual analog scales (VASs) for the quality of CCD based on general patient satisfaction, masticatory function, ability to speak, comfort, stability, retention and aesthetics. Data were analysed using the Wilcoxon signed-rank test, the Kruskal-Wallis test and Mann-Whitney test via SPSS version 18.0 (α = 0.05). Thirty participants completed the follow-up period for PGFO group. The mean age ± standard deviation of the new participants was 57.97 ± 6.93 years. Participants reported significantly less satisfaction in terms of comfort, stability and retention of denture with PGFO compared to balanced groups. Also, using OHIP-EDENT questionnaire, significantly higher physical pain score was noted for PGFO group compared to BO and LO. Higher physical disability score was noted in PGFO compared to LO. Participants receiving CCDs with PGFO reported lower satisfaction in terms of comfort, stability and retention of denture and higher physical pain and physical disability than the balanced occlusal schemes.

Evaluation of Satisfaction Perceived by Prosthetic Patients Compared to Clinical and Technical Variables

Objectives:

The purpose of this study is to relate the clinical quality of the complete denture and specific anamnestic factors to the level of satisfaction perceived by patients. Also identifying possible prognostic parameters that could be predictive of future satisfaction.

Materials and Methods:

On the basis of a substantial existing literature, the most appropriate parameters to determine the prosthetic quality have been determined to evaluate the satisfaction perceived by patients about their denture; a completely new questionnaire has been drawn up. Ninety-eight patients have been included in the research, they have undergone a clinical examination, and they have filled out the questionnaire anonymously. The ANOVA test and Pearson correlation test have been employed to relate clinical and anamnestic factors to the overall satisfaction score.

Results:

The average level of patients’ satisfaction was between “quite satisfied” and “very satisfied.” There is no significant variability of satisfaction related to the type of prosthesis. The ANOVA test did not verify relationships between the overall satisfaction score and the anamnestic data examined. Pearson linear correlation coefficient between the overall prosthetic quality and the general satisfaction perceived by patients is 0.493 (P < 0.01). Extension of the prosthetic body (r = 0.478; P < 0.01) and retention (r = 0305; P < 0.05) are in correlation with the overall patients’ satisfaction.

Conclusion:

there is a moderately strong relationship between the overall prosthetic quality and the general satisfaction perceived by patients. Particularly, the retention and the adequate extension of the prosthetic body appear to be factors that are most associated with satisfaction. Instead, the anamnestic factors are not related to overall satisfaction score.

Implant Inclination and Horizontal Misfit in Metallic Bar Framework of Overdentures: Analysis By 3D-FEA Method

Abstract The aim of this study was to evaluate by three-dimensional finite element analysis (3D-FEA) the biomechanics involved in bar-framework system for overdentures. The studied factors were latero-lateral angulation in the right implant (-10, -5, 0, 5 and 10 degrees), and different bar cross-sections (circular, Hader and oval) presenting horizontal misfits (50 or 150 µm) on the opposite implant. Positive angulation (5 and 10 degrees) for implant inclination to mesial position, negative angulation (-5 and -10 degrees) for distal position, and zero degree for parallel implants. The von Mises stresses evaluated the bar, screw and the implant; maximum principal, minimum principal and shear stress analyses evaluated the peri-implant bone tissue. Parallel implants provide lower stress in alveolar bone tissue; mesial inclined bars showed the most negative effect on prosthetic structures and implants. In conclusion, bar cross-section showed no influence on stress distribution for peri-implant bone tissue, and circular bar provided better behavior to the prosthetic system. Higher stress concentration is provided to all system as the misfit increases.

Mandibular Implant-supported Overdentures: Prosthetic Overview

Implant-supported overdentures are becoming the treatment of choice for the completely edentulous mandible. They significantly improve the quality of life in edentulous patients. For this review article, the literature was searched to identify pertinent studies. No meta-analysis was conducted because of high heterogeneity within the literature. Accordingly, in this review article, the author provides an update on implant-supported mandible overdentures with regard to the number of implants, type of loading, stress-strain distribution, mode of implant-to-denture attachment, occlusal considerations and complications.

Impact of Removable Partial Dental Prostheses on the Oral Health-Related Quality of Life of a South African Cohort with Varied Distributions of Missing Posterior Teeth

PURPOSE

To determine the impact of removable partial dental prostheses on satisfying the daily functioning and quality of life (QoL) of adult patients with different distributions of missing posterior teeth.

MATERIALS AND METHODS

A cross-sectional interventional study was carried out on 80 patients having variously distributed posteriorly shortened and interrupted arches. Treatment comprised provision of partial dentures by senior dental students, supervised by senior clinical teachers who had knowledge of the potential benefits of the shortened dental arch (SDA) concept. The Oral Impacts on Daily Performance Index was completed before and 6 months after prosthetic treatment across groups comprising Kennedy Classes I, II, and III arches. Analysis included descriptive statistics and associations and comparisons between variables.

RESULTS

Mean age of patients was 57.4 years (SD = 13.1), many were retired (72.2%), and a majority were females (60%). Most patients lived in urban areas (95%), and were largely unemployed (63.3%). At pretreatment, only 31.3% of patients reported having good dental health and satisfaction with their current oral state, while 82.5% said they had a great need for treatment. The negative oral impacts that were most frequently experienced were those of eating (67.5%), smiling (50%), and being emotionally disturbed (63.8%). Post-treatment, 76.3% indicated good oral health and satisfaction with no significant differences between the 3 Kennedy groups. Any further negative impacts were reported mostly for Kennedy Classes I and II.

CONCLUSIONS

Overall, significant reductions of negative impacts were observed following treatment with dentures, across the 3 Kennedy groups, with respect to improved function, satisfaction, and oral health-related QoL. The findings confirm the reliance by partially dentate patients in all 3 Kennedy groups on dentures for improved oral health, although the possible benefits of the SDA concept as an alternative treatment option was not specifically explored.

Patient satisfaction with occlusal scheme of conventional complete dentures: A randomised clinical trial (part I)

BACKGROUND

Occlusal scheme can affect denture retention, stability, occlusal force distribution, aesthetics, masticatory function, patient comfort and general patient satisfaction with dentures.

OBJECTIVES

This study aimed to compare the patient satisfaction with 3 types of complete denture occlusion including fully bilateral balanced occlusion (FBBO), newly presented buccalised occlusion (BO) and lingualised occlusion (LO).

METHODS

In this parallel randomised clinical trial, new conventional complete dentures were fabricated for 86 volunteers. Participants were randomly allocated to 3 groups with 3 different occlusal schemes. All patients were recalled at 1 and 3 months after delivery for data collection. The 19-item version of Oral Health Impact Profile for Edentulous Patients questionnaire was used in this study. The visual analogue scale (VAS) was used for assessment of the prosthodontist's attitude towards denture quality, patient's attitude towards different occlusal schemes and evaluation of patient satisfaction. Data were analysed using the Wilcoxon signed rank test, the Kruskal-Wallis test and the post hoc Dunn test via SPSS version 18.0 (P ≤ .05).

RESULTS

Eighty-six patients completed the study, and their data were analysed (mean age ± standard deviation = 57.78 ± 9.98 years). The only significant difference when comparing the 3 groups was physical pain, which was significantly higher in FBBO group. No significant differences were found for the VAS scores of patient and prosthodontist satisfaction or the domain scores among the 3 occlusal schemes either at 1 or at 3 months post-delivery. The VAS score of patient satisfaction and prosthodontist satisfaction increased at third compared to first month after delivery.

CONCLUSION

The results of this randomised clinical trial provided evidence that BO is as effective as LO for the fabrication of complete dentures.

Mandibular complete denture versus single-implant overdenture: a systematic review of patient-reported outcomes

The single-implant mandibular overdenture (SIMO) has been proposed as an alternative for edentulous patients who are poorly adapted to their dentures due to low retention and stability of the conventional mandibular complete denture (CD). However, there is a lack of evidence regarding the effectiveness of SIMO, which can be measured by examining patient perception of treatment effects. The aim of this systematic review was to assess the comparative results of CD and SIMO treatments using patient-reported outcome measures. A literature search was carried out in PubMed, Scopus and Cochrane Central databases. The search included studies published up to July 2017. The focus question was: 'Do single-implant mandibular overdentures improve patient-reported outcomes compared to conventional complete dentures in edentulous patients?' Eligible studies were randomised clinical trials (RCT) and prospective studies. After initial screening for eligibility and full-text analysis, 11 studies were included for data extraction and quality assessment (five parallel-group RCTs, two crossover RCTs and four prospective studies). All studies reported marked improvement in satisfaction with the dentures and quality of life measures after SIMO treatment, irrespective of variations in implant treatment protocols and retention systems. Methodological considerations revealed a lack of evidence from RCTs on the comparative effectiveness of the two treatment strategies. Hence, although available evidence suggests considerable improvement in patient-reported outcomes following the insertion of a single implant to retain a mandibular denture, further well-designed comparative studies between SIMO and CD are required to improve the level of evidence and to support the indication of SIMO treatment in routine practice.

Three-year Prospective Evaluation of Immediately Loaded Mandibular Implant Overdentures retained with Locator Attachments

INTRODUCTION

Immediate implant-loading protocol has progressed because of various clinical advantages offered by this treatment approach. However, available studies on edentulous patients are still few compared to those in which delayed implant-loading protocol was applied.

AIM

This prospective study was to evaluate the implant survival rate and the peri-implant tissue response in a group of patients who received two unsplinted immediately loaded dental implants in the mandibular anterior region to retain a complete overdenture using locator attachments.

MATERIALS AND METHODS

A total of 24 edentulous patients with a mean age of 63.4 years were involved in this study following certain inclusion criteria. All patients received a new set of complete dentures before implant positioning. Two Prima Connex tapered implants were put in the interforaminal area of the mandible with a flapless surgical procedure, and the prefabricated dentures were immediately retained with a zest locator attachment. Clinical and radiographic records of the patients were reviewed immediately after placement of the implant, at 3 months, and at 1, 2, and 3 years following fixture installation. The obtained data were analyzed using paired samples t-test and the Wilcoxon signed-rank test at 0.05 significance level.

RESULTS

At 3 years, all implants had osseointegrated with a 100% survival rate. In addition, the total mean marginal bone change was -0.89 ± 0.14 mm, and the mean periotest value was -7.631 ± 0.921.

CONCLUSION

Results of this study propose that immediate loading of mandibular implant overdentures that are retained with locator attachments was a feasible treatment alternative for this particular group of patients.

CLINICAL SIGNIFICANCE

Immediate implant- loading of mandibular implant overdentures that are retained with locator attachments is a reliable treatment option Keywords: Immediate implant loading, Implant survival rate, Locator attachments, Overdenture.

Fabrication of denture base materials with antimicrobial properties

STATEMENT OF PROBLEM

Acrylic resin denture base resins are colonized by oral and nonoral bacteria and Candida species. This reservoir of microorganism causes denture stomatitis, which can be implicated in some life-threating infections in older denture wearers.

PURPOSE

The purpose of this in vitro study was to incorporate quaternized N,N-dimethylaminoethyl methacrylate (DMAEMA) monomer into a denture base resin and investigate its antimicrobial and mechanical properties.

MATERIAL AND METHODS

Quaternized ammonium monomer (QAM) was synthesized through the reaction of octyl bromide and DMAEMA. The synthesized QAM was incorporated into a denture base resin system (8 to 12 wt%). The resulting material was characterized by Fourier transform infrared spectroscopy. The in vitro antimicrobial property was determined by direct contact test against Escherichia coli, Staphylococcus aureus, and Candida albicans. Release of the QAM was also tested by means of an agar diffusion test. Mechanical properties were measured with a 3-point bend test, and results were analyzed and compared using ANOVA and the Tukey post hoc test (α=.05).

RESULTS

Spectroscopy confirmed the formation of quaternized ammonium modified denture base (QAMDB). The decrease in number of viable cells of E coli, S aureus, and C albicans was more than 99% for 12%-QAMDB in comparison with that of the control groups. An overall decline was observed in the flexural strength and flexural modulus of the fabricated resins (P<.05), but no differences were observed for strain at break or fracture work of the specimens (P>.05).

CONCLUSIONS

Denture base resins containing immobilized QAM provided high antibacterial activity, but the flexural strength and flexural modulus of the denture base resins decreased.

PMMA denture base material enhancement: a review of fiber, filler, and nanofiller addition

This paper reviews acrylic denture base resin enhancement during the past few decades. Specific attention is given to the effect of fiber, filler, and nanofiller addition on poly(methyl methacrylate) (PMMA) properties. The review is based on scientific reviews, papers, and abstracts, as well as studies concerning the effect of additives, fibers, fillers, and reinforcement materials on PMMA, published between 1974 and 2016. Many studies have reported improvement of PMMA denture base material with the addition of fillers, fibers, nanofiller, and hybrid reinforcement. However, most of the studies were limited to in vitro investigations without bioactivity and clinical implications. Considering the findings of the review, there is no ideal denture base material, but the properties of PMMA could be improved with some modifications, especially with silanized nanoparticle addition and a hybrid reinforcement system.

Teaching mandibular implant-Supported overdentures in dental schools in North America - a survey

INTRODUCTION

Mandibular two-implant overdentures are considered the minimum standard of care for edentulous patients and provide an excellent performance, as well as satisfaction to the patients. Dental schools are required to promote the teaching of current treatment options in order to enable students to master state-of-the-art procedures.

AIMS

The purpose of this study was to examine how the theoretical and practical aspects of mandibular two-implant overdentures are taught in dental schools in North America.

METHODS

Data were collected via an online questionnaire that included questions regarding the theoretical and clinical courses, surgical procedure and imaging method.

RESULTS

Of 75 schools, 36 responded to the survey. Almost all the schools teach the subject theoretically, but it is not mandatory for students to perform in most of the schools. Only a minority (23%) of the mandibular dentures made by students are implant-supported. Almost all of the schools (94%) use two implants to support overdentures, and Locator abutment is used almost exclusively. The prevalent imaging for the surgical procedure is CT scans, although 30% of the schools use panoramic radiograph. None of the schools loads the implants immediately after surgery.

CONCLUSION

Some clear trends are apparent in the current survey: the use of two implants, no use of bar connectors and delayed loading of the implants. It is likely that graduates will not have sufficient clinical skills and will need continuing education to be familiar with the required procedures, both surgical and prosthetic.

Case-based learning: A study to ascertain the effectiveness in enhancing the knowledge among interns of an Indian dental institute

OBJECTIVE

Time and again, it has been shown that active learning promotes critical thinking, and this environment has to be fostered in dental education too. Therefore, the present study was carried out with an aim to know the effectiveness of case-based learning (CBL) in enhancing the knowledge of dental interns of a dental institute in India.

MATERIALS AND METHODS

This pre-post single-blinded, experimental study was conducted in two sessions on a purposive sample of 45 dental interns who gave informed consent. The interns answered a pretest questionnaire comprising questions related to their knowledge of hyperplastic tissue in complete denture patients. The interns were randomly allocated into three subgroups for thorough discussion. Each group viewed all three parts of a case related to hyperplastic tissue and presented the case in the presence of a facilitator. The facilitator discussed the subject with the three subgroups. A post-test was conducted immediately, and the results were compared with the pretest. The facilitator explained about hyperplastic tissue with an audio-visual aid after the post-test was administered. The perception of interns toward CBL was assessed by a standard questionnaire.

RESULTS

On analysis, the comparison of the overall knowledge scores pre- and post-CBL showed a statistically significant increase from 9.8 ± 2.14 to 12.6 ± 1.37 (P < 0.001).

CONCLUSION

CBL proved to be effective in enhancing the knowledge of dental interns.

Fretting Corrosion Behavior of Experimental Ti-20Cr Compared to Titanium

Experimental cast titanium alloys containing 20 mass% chromium (Ti-20Cr) show preferable mechanical properties and a good corrosion resistance. This study evaluated the fretting corrosion behavior of Ti-20Cr. Ti-20Cr (n = 4) and commercially pure titanium (CP-Ti, n = 6) disk specimens were used. The fretting corrosion test was performed by electrochemical corrosion at 0.3 V in 0.9% saline solution and mechanical damage using 10 scratching cycles with three different scratching speeds (10–40 mm/s) at 10 N. After testing, the activation peak, repassivation time and surface morphology of each specimen were analyzed. The differences between the results were tested by parametric tests (α = 0.05). The average activation peaks were significantly higher in CP-Ti than in Ti-20Cr (p < 0.01), except at 20 mm/s. In the series of scratching speeds, faster scratching speeds showed higher activation peaks. The maximum activation peaks were also higher in CP-Ti. Slight differences in the repassivation time were observed between the materials at every scratching speed; faster scratching speeds showed shorter repassivation times in both materials (p < 0.05). CP-Ti showed severe damage and significantly higher wear depth than Ti-20Cr (p < 0.05). In conclusion, adding chromium to titanium reduced surface damage and improved the fretting corrosion resistance.

Design and fabrication of complete dentures using CAD/CAM technology

The aim of the study was to test the feasibility of using commercially available computer-aided design and computer-aided manufacturing (CAD/CAM) technology including 3Shape Dental System 2013 trial version, WIELAND V2.0.049 and WIELAND ZENOTEC T1 milling machine to design and fabricate complete dentures.The modeling process of full denture available in the trial version of 3Shape Dental System 2013 was used to design virtual complete dentures on the basis of 3-dimensional (3D) digital edentulous models generated from the physical models. The virtual complete dentures designed were exported to CAM software of WIELAND V2.0.049. A WIELAND ZENOTEC T1 milling machine controlled by the CAM software was used to fabricate physical dentitions and baseplates by milling acrylic resin composite plates. The physical dentitions were bonded to the corresponding baseplates to form the maxillary and mandibular complete dentures.Virtual complete dentures were successfully designed using the software through several steps including generation of 3D digital edentulous models, model analysis, arrangement of artificial teeth, trimming relief area, and occlusal adjustment. Physical dentitions and baseplates were successfully fabricated according to the designed virtual complete dentures using milling machine controlled by a CAM software. Bonding physical dentitions to the corresponding baseplates generated the final physical complete dentures.Our study demonstrated that complete dentures could be successfully designed and fabricated by using CAD/CAM.

Influence of the renewal of removable dentures on oral health related quality of life

Background

The renewal of removable dentures is often suggested to denture wearers subject to discomfort. However, the impact of this rehabilitation on patients’ oral health related quality of life and their removable dentures related satisfaction is still unknown. This study was aimed at assessing these patient-centered outcomes and the potential impact of different factors.

Methods

A cohort of 116 patients in need of removable dental prostheses rehabilitation was recruited at a dental hospital over a period of 1 year. The subjects were separated into two groups according to their prosthesis experience (group in need of removable dentures renewal/group needing an removable dentures for the first time). Subjects were asked to answer the “Geriatric Oral Health Assessment Index” (GOHAI) and the “McGill Denture Satisfaction Instrument” before and after a prosthesis integration period (9–12 weeks).

Results

GOHAI scores were slightly higher for patients with removable dentures renewal (from 40.6 ± 10.3 to 47.1 ± 10.0, p < 0.001), independently of the type of prosthetic rehabilitation. However, the scores of the GOHAI functional field did not change. Subjects with no removable dentures experience presented an increase in their functional GOHAI score (p < 0.001). Regarding patient removable dentures related satisfaction, only the “Esthetic” (p < 0.001), “Chewing efficiency” (p < 0.001) and “Oral condition” (p < 0.01) items increased after prosthesis renewal.

Conclusions

This study showed that renewing removable dentures only moderately improved the oral health related quality of life and removable dentures related satisfaction of patients, regardless of age, gender or type of rehabilitation. Other tasks are necessary such as the analysis of physiological parameters and qualitative research on patient’s expectations.

Cost-effectiveness analysis of the single-implant mandibular overdenture versus conventional complete denture: study protocol for a randomized controlled trial

Background

Preliminary clinical studies on the single-implant mandibular overdenture (SIMO) have reported favorable results as an alternative to the conventional complete dentures for rehabilitation of the edentulous mandible. Clinical and patient-reported outcomes were assessed but no evidence is available with respect to the cost-effectiveness of this treatment, which is particularly important to test whether the incremental cost associated with the implant treatment is justified facing the benefits from the intervention. Thus, the aim of this study is to assess the cost-effectiveness of single-implant mandibular overdentures.

Methods/design

This randomized clinical trial will include edentulous individuals who meet eligibility criteria. Participants will be randomized into one of the treatment groups: a conventional complete denture group or a single-implant mandibular overdenture group. Direct costs related to therapies in both groups will be identified, measured and valuated for 1 year after treatment. Oral health-related quality of life and satisfaction with the dentures will be the primary outcome variables. Incremental cost-effectiveness ratios will be estimated and graphically presented on cost-effectiveness planes. A Markov decision tree will be constructed to set out the consequences of the competing alternatives. Sensitivity analysis on the most important assumptions will be performed in order to assess the robustness of the model.

Discussion

This is the first trial-based cost-effectiveness study on single-implant mandibular overdentures. Specific challenges in designing the protocol are considered. The expected results are of high clinical relevance and may contribute to the decision-making process when choosing between different alternatives for the rehabilitation of the edentulous mandible.

Trial registration

ClinicalTrials.gov Identifier: NCT02710357, registered on 11 March 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1646-0) contains supplementary material, which is available to authorized users.

Predictors of Patient Satisfaction with Removable Denture Renewal: A Pilot Study

PURPOSE

Conventional removable dentures still play an important role in the treatment of lost teeth. A thorough understanding of the parameters that influence patient satisfaction is useful for deciding whether denture replacement is meaningful. From a clinical perspective, factors that can be measured before starting treatment are relevant. This pilot study investigated whether patient satisfaction after denture renewal was affected by aspects related to the old prostheses, type of jaw, and patient motivation for denture renewal.

MATERIALS AND METHODS

Fifty subjects (mean age 68.2 ± 8.4) were provided with 74 removable dentures (partial n = 20, complete n = 54). Satisfaction was assessed before treatment and 3 months after new prosthesis insertion. Total satisfaction 3-month post-insertion (TSP3) merged 6 individual satisfaction items measured after treatment. Change of total satisfaction 3-month post-insertion (CTS3) represented the difference of total satisfaction when old and new prostheses were compared. The effect of the following independent variables was investigated: reason patients requested new dentures (fit, esthetics, broken denture, wear, advice of dentist, extractions), satisfaction with the old prosthesis (general, retention, stability, comfort, pronunciation, chewing, esthetics), and technical quality of the old prostheses as assessed by a dentist (stability, retention, fit, border, wear, esthetics). Gender, age, and a cognitive screening test were included as confounding variables. Mann-Whitney-U tests and linear mixed model analysis were performed.

RESULTS

All individual satisfaction items significantly improved with new prostheses for maxillary and mandibular jaws. TSP3 was higher for maxillary prostheses, if retention satisfaction with the old prosthesis was good, and if the dentist assessed the esthetics of the old prosthesis as deficient. CTS3 was associated with male gender, dissatisfaction with chewing before treatment, and dissatisfaction with esthetics before treatment.

CONCLUSIONS

This pilot study showed that satisfaction 3 months after new denture insertion was associated with aspects of satisfaction and quality related to the old prosthesis, type of jaw, and gender. These factors may help dentists predict therapeutic benefits when deciding on the need for denture replacement. Further research should be done with a greater number of subjects and should include balanced quantities of the different types of dentures.

Prognoses of new complete dentures from the patient's denture assessment of existing dentures

OBJECTIVES

The aim was to determine prognostic factors affecting frequent post-delivery adjustments of new complete dentures using patients' assessments of existing complete dentures.

MATERIALS AND METHODS

A total of 125 edentulous participants (56 men, 69 women; mean age, 76.4 years) who required new complete dentures evaluated existing dentures using the patient's denture assessment (PDA), a questionnaire regarding the self-assessment of dentures composed of 22 question items and containing six subscales: "function," "lower denture," "upper denture," "expectation," "esthetics and speech," and "importance." Moreover, the numbers of post-delivery adjustments of new dentures were recorded. A multiple logistic regression analysis was performed to identify significant factors for frequent adjustments of new dentures with five subscales of the PDA (excluding "importance"), level of mandibular ridge resorption, and age as independent variables.

RESULTS

The analysis showed that "function," "esthetics and speech," and level of mandibular ridge resorption were significant variables for a frequent number of post-delivery adjustments of new complete dentures.

CONCLUSIONS

The results suggested that patients' assessments of existing dentures using the PDA might allow a prediction of prognosis for complete denture treatments. Additionally, low "function" scores and high "esthetics and speech" scores for existing dentures and high levels of mandibular ridge resorption were significant prognostic factors affecting frequent post-delivery adjustments of new complete dentures.

CLINICAL RELEVANCE

It may be difficult for edentulous persons to adapt to new complete dentures, especially those who have complaints about mastication and swallowing with existing dentures and poor mandibular ridges, but are satisfied with esthetics and speech.

Wearing complete dental prostheses - Effects on perioral morphology

Background

To adequately perform rehabilitation of edentulous patients by a complete removable dental prosthesis (CRDP) is from basic interest to dentists to understand the morphologic changes caused by re-establishment of a physiologic jaw relationship. Anthropometric analyses of standardized frontal view and profile photographs may help elucidate such changes.

Material and Methods

Photographs of 31 edentulous patients were compared in relaxed lip closure and after insertion of a CRDP in stable occlusion. 2232 anthropometric distances were raised. Eighteen anthropometric indices reflecting the perioral morphology and its integration in the vertical facial harmony were investigated.

Results

The intercanthal – mouth width index (p<.001), medial - lateral cutaneous upper lip height index (p=.007), lower vermilion contour index (p=.022), vermilion - total upper lip height index (p=.018), cutaneous - total upper lip height index (p=.023), upper lip - nose height index (p=.001), nose - upper face height index (p=.002), chin - mandible height index (p=.013), upper lip - mandible height index (p=.045), nose - lower face height index (p=.018), and nose - face height index (p=.029) showed significant pre- to post-treatment changes.

Conclusions

The investigated anthropometric indices presented reproducible results related to an increase in occlusal vertical dimension. Their application may be helpful in assessment, planning, and explanation of morphologic effects of CRDPs on the perioral and overall facial morphology, which may helps to improve the aesthetic outcome.

Key words:Dentures, removable dentures, anthropometry, perioral morphology.

Reliability and Validity of a Nepalese Version of the Oral Health Impact Profile for Edentulous Subjects

PURPOSE

To assess the reliability and to validate the translated Nepalese version of the Oral Health Impact Profile (OHIP-EDENT-N) in Nepalese edentulous subjects.

MATERIALS AND METHODS

The international guidelines for translation and cross-cultural adaption of OHIP-EDENT were followed, and a Nepalese version of the questionnaire was adapted for this study. Eighty-eight completely edentulous subjects were then selected for the study and completed their responses for the questionnaire. The reliability of the OHIP-EDENT-N was evaluated using internal consistency. Validity was assessed as construct and convergent validity. Construct validity was determined using exploratory factor analysis (EFA). The correlation between OHIP-EDENT-N subscale scores and the global question was investigated to test the convergent validity.

RESULTS

Cronbach's alpha for the total score of OHIP-EDENT-N was 0.78. Construct validity was assessed by factor analysis: 70.196% of the variance was accountable to five factors extracted from the factor analysis. Factor loadings above 0.40 were noted for all items. In terms of convergent validity, significant correlations could be established between OHIP-EDENT-N and global questions.

CONCLUSIONS

This study has been able to establish the reliability and validity of the OHIP-EDENT-N, and OHIP-EDENT-N can be a considered a reliable tool to assess the oral health related quality of life in the Nepalese edentulous population.

The importance of a two-step impression procedure for complete denture fabrication: a systematic review of the literature

The literature has questioned the real need for some clinical and laboratory procedures considered essential for achieving better results for complete denture fabrication. The aim of this study was to review the current literature concerning the relevance of a two-step impression procedure to achieve better clinical results in fabricating conventional complete dentures. Through an electronic search strategy of the PubMed/MEDLINE database, randomised controlled clinical trials which compared complete denture fabrication in adults in which one or two steps of impressions occurred were identified. The selections were made by three independent reviewers. Among the 540 titles initially identified, four studies (seven published papers) reporting on 257 patients evaluating aspects such as oral health-related quality of life, patient satisfaction with dentures in use, masticatory performance and chewing ability, denture quality, direct and indirect costs were considered eligible. The quality of included studies was assessed according to the Cochrane guidelines. The clinical studies considered for this review suggest that a two-step impression procedure may not be mandatory for the success of conventional complete denture fabrication regarding a variety of clinical aspects of denture quality and patients' perceptions of the treatment.

Some issues related to evidence-based implantology

This article reviews relevant dental literature to answer some frequent questions related to evidence-based implantology. There are hundreds of implant systems on the market, but the majority lack clinical documentation. Recommended number of implants for full-arch fixed prostheses is four or five in the mandible but at least six in the maxilla. Less expensive implant-retained overdentures make implant treatment available to a greater portion of edentulous subjects. Mandibular overdentures on two implants, and even one implant, have shown excellent long-term outcomes. In the maxilla, less than four implants are not recommended for good results. Single implant restorations have good prognosis, but placement of the implant should be postponed until adulthood. Osseointegrated implants have revolutionized clinical dentistry. However, in a global perspective, implants make up only a small part of all prosthodontic treatment. Knowledge and skill in conventional prosthodontics must be maintained as it will remain the most common part of the specialty.

An in vitro comparative study to evaluate the retention of different attachment systems used in implant-retained overdentures

Aim:

The aim of this in vitro study was to compare the change in the retentive force and removal torque of three attachment systems during simulation of insertion-removal cycles.

Methodology:

Edentulous mandibular models were made with heat-cured polymethyl methacrylate resin. Two implant replicas (CMI), of 3.75 mm diameter and 10 mm length, were placed in the intraforaminal region. Acrylic resin mandibular overdentures were fabricated and provision was made to receive three different overdenture attachment systems, prefabricated ball/o-ring attachment (Lifecare Biosystems, Thane, India), Hader bar and clip attachment (Sterngold, Attleboro, MA), and Locator^® implant overdenture attachment stud type (Zest Anchors LLC, USA). Using a universal testing machine, each of the models were subjected to 100 pulls each to dislodge the overdenture from the acrylic model, and the force values as indicated on the digital indicator were tabulated both before and after thermocycling (AT).

Statistical Analysis Used:

Statistical analysis comprised Kolmogorov–Smirnov test, Friedman test, and Wilcoxon signed ranks test.

Results:

The statistical model revealed a significantly different behavior of the attachment systems both before and AT. The ball/o-ring and bar attachments developed higher retentive force as compared to the locator attachment. The bar and clip attachment exhibited the highest peak as well as the highest mean retention force at the end of the study. The Locator^® attachment showed a decrease in retentive potential after an early peak.

Conclusions and Clinical Implications:

The ball/o-ring and bar and clip attachments exhibit higher retentive capacities than the Locator^® attachment over time.

Functional adaptation of the masticatory system to implant-supported mandibular overdentures

OBJECTIVES

The purpose of this study was to investigate the adaptation behavior of the stomatognathic system after immediate loading (24 to 72 h after surgery) of two implants supporting mandibular overdentures, assessed on insertion and three months later. The study hypothesis was that insertion of the overdentures would significantly change masticatory performance and muscle activity at both times.

MATERIAL AND METHODS

Thirty subjects (nine female, mean age 69.64 ± 11.81 years; 21 male, mean age 68.67 ± 7.41 years) who participated in a randomized clinical trial were included in the study. Each patient was examined three times: (i) at baseline, after already having worn new dentures for three months (T1); (ii) immediately after insertion of the overdentures on the implants (T2); and (iii) after an adaptation period of three months (T3). Examination comprised assessment of masticatory performance with artificial test food (Optocal), and simultaneous bilateral surface EMG recording of the masseter and anterior temporalis muscles. Particle-size distribution (representative value X₅₀ ), maximum muscle contraction (MVC), and total muscle work (TMW; area under the curve) were compared by use of repeated-measures analysis of variance (ANOVA).

RESULTS

At T3, all measured variables (i.e., masticatory performance and muscle activity) were significantly different from those at T1. At T2, no significant changes were observed. The study hypothesis had to be rejected for T2 but accepted for T3.

CONCLUSION

Functional rehabilitation (in terms of masticatory performance and masticatory muscle activity) does not occur immediately after immediate loading of two implants with mandibular overdentures, but requires a significant time for functional improvement.

Does periodical department audit really works to make things fall in place: A Geriatric/General Oral Health Assessment Index based audit in prosthodontics

Purpose:

The purpose was to assess the outcome of improved staff supervision on the efficiency and quality of complete dentures delivered by clinical students.

Materials and Methods:

The audit was performed in two parts. In the first cycle, retrospective analysis for complete dentures delivered by clinical students was undertaken, and patient's satisfaction was graded using Geriatric/General Oral Health Assessment Index (GOHAI). All the impeding factors encountered in the first cycle were identified, and corrective measures were implemented. Subsequently, a prospective analysis for the dentures delivered under strict staff supervision was undertaken in the second cycle. Patient satisfaction was graded again using GOHAI.

Results:

Improved staff supervision increased the patient satisfaction significantly.

Conclusions:

The quality of care had improved in leaps and bounds compared to the first cycle due to increased level of supervision and strict adherence to the recommendations made at the end of the first cycle.

Nitric Oxide Concentration and Other Salivary Changes after Insertion of New Complete Dentures in Edentulous Subjects

Objective. To assess changes in levels of salivary nitric oxide (NO) after insertion of new complete dentures and its association with clinical and salivary parameters. Methods. Nineteen fully edentulous subjects were included, mean age 64.4. Unstimulated whole saliva was collected before and after insertion of the dentures, at follow-up visits, and after 12 months. The concentration of the final stable NO product (nitrite) was measured by a colorimetric assay based on the Griess reaction. Clinical parameters were assessed during all clinical visits. Results. Functional adaptation to the dentures progressively improved, with no complaints at the long-term follow-up. NO concentration was not influenced by the level of functional adaptation, presence of injuries to the mucosa, salivary flow, and saliva viscosity. Pairwise comparison showed a reduction in NO concentration at the first follow-up compared to baseline values but differences were not statistically significant. Significant differences were observed in NO concentrations at the long-term follow-up when compared to the first (p = 0.024) and second (p = 0.027) visits. Conclusion. NO concentration reduced after denture insertion and returned to baseline levels in the long-term follow-up. This appears to be an autonomic response of the body and provides valuable complementary information for the management of the edentulous patient.

Simplified Complete Denture: A Systematic Review of the Literature

PURPOSE

Many procedures are used to construct traditional (T) complete dentures; however, a simplified (S) method requiring fewer steps and less time is available. This systematic review intends to summarize the modeling of simplified methods for complete dentures and evaluate the differences between the T method and S method. With this review, we hope to lay the foundation for proposing a standardized fabrication method for "simplified dentures."

METHODS

The MEDLINE (via PubMed) and EMBASE databases were searched for articles on simplified complete dentures published in English before April 2014. Eleven articles were included. One was about one-step complete dentures, two were about SET (simplified treatment of edentulous patients), and the others were about the normal simplified method, which includes impression, occlusal registration, and try-in. Seven were randomized controlled clinical trials (RCTs). The time, cost, patient satisfaction, clinical effects, masticatory performance, masticatory ability, and professional evaluation reported in these studies were compared.

RESULTS

We summarized the different techniques of fabricating complete dentures and discussed the RCTs of the normal complete technique. None of the RCTs identified significant differences between the S and T groups in terms of patient ratings for general satisfaction, OHIP-edentulous scale, denture quality, or masticatory ability. At the same time, the T method was significantly more expensive and required more time to complete than the S method.

CONCLUSIONS

Current scientific evidence suggests that the S method can replace or partly replace the T method. Moreover, specific rules should be devised to restrict the simplified construction, and detailed research should be conducted.

Different Occlusal Schemes in a Persistent Protruding Complete Denture Wearer

Different types of artificial teeth and occlusal designs can be used in complete dentures. Bilateral balanced occlusion, lingualized occlusion, canine guidance, and monoplane are the main occlusal designs; however there is no agreement on which tooth arrangement is ideal for achieving success in complete dentures. This report presents an alternative for persistent involuntary protruding complete denture wearers through the use of artificial teeth with higher cusps. Due to an old and worn pair of complete dentures, the patient had the habit of protruding. New dentures were made with Biotone artificial teeth and in the trial session, the patient would still protrude. A new set was made with Premium artificial teeth, which present higher cusps. With these dentures, the involuntary protrusion did not occur. From the delivery to the follow-up sessions, the patient stopped protruding.

Characteristics of the pain tolerance threshold induced by electrical stimulation of the alveolar ridge

The purpose of this study was to determine the characteristics of the pain tolerance threshold (PTT) induced by electrical stimulation of the alveolar ridge. A total of 100 healthy volunteers studying or working at Nihon University School of Dentistry at Matsudo and patients from Nihon University School of Dentistry at Matsudo Affiliated Hospital, including 51 men (58.7 ± 17.6 years old) and 49 women (60.7 ± 17.1 years old), participated in this study. The volunteers were enrolled after obtaining written informed consent. PTT measurements were obtained using a Neurometer CPT/C® device to deliver electrical stimulation around the left greater palatine foramen at frequencies of 5 and 250 Hz. When the stimulus could no longer be tolerated, the participant released a button to automatically discontinue the stimulus. After the distribution of the PTT values was analyzed, the influence of gender, age, and Eichner index on PTT was analyzed. The Eichner index values were divided into three categories: group A (four supporting zones), group B (less than four supporting zones but with anterior tooth contact), and group C (no occlusal contact). The PTT values did not show a normal distribution. There were no significant differences in PTT between men and women. PTT was significantly associated with age (P = 0.017) at 5 Hz in men. There were no significant differences in PTT among the Eichner index groups. The characteristics of the PTT of the alveolar ridge are as follows: (1) age and PTT at 5 Hz are significantly associated with men but not with women, and (2) the Eichner index has no influence on the PTT.