Quality of Life, Satisfaction, Occlusal Force, and Halitosis after Direct and Indirect Relining of Inferior Complete Dentures

An Evaluation of Reference Bite Force Values: Investigating the Relationship Between Dental Prosthetic Restoration and Bite Force in a Cross-Sectional Study

Objectives: This study aimed to establish reference values for bite force in individuals with various prosthetic restorations and to examine the relationship between prosthetic treatment groups (PTGs) and bite force as an indicator of masticatory muscle function. Materials and Methods: In a cross-sectional study from November 2021 to March 2023, 198 participants aged 18 to 95 years were recruited from multiple dental and geriatric centers. The participants were assigned to seven PTGs based on their dental and prosthetic statuses. Bite force was measured using the Occlusal Force Meter GM10, with three recordings on each side of the jaw, and analyzed using ANOVA. Results: The bite force decreased with fewer teeth and the transition from fixed to removable dentures. Fully dentate participants exhibited the highest bite forces, differing significantly from the other groups (p < 0.001). For the fully dentate individuals (547 ± 240 N), the bite force decreased progressively with the extent of prosthetic restoration, reaching 55 ± 45 N in edentulous individuals with complete dentures in both jaws. However, edentulous participants with two interforaminal implants demonstrated higher bite forces than those with partial dentures. Conclusions: Bite force is significantly impacted by prosthetic restoration type. Fully dentate individuals have the highest bite forces, while edentulous patients with implant-supported dentures also show considerable bite forces, similar to those with partial dentures.

Evaluation of the bond strength, surface roughness and wettability between 3D-printed denture base resin to denture lining material to different surface treatments

Background

The low bond strength between 3D-printed denture base resin and denture lining material is due to the difference in chemical structure, which justifies the use of methods to increase such bond. This study aims to examine the influence of different surface treatments on the bond strength, surface roughness, and wettability between 3D-printed denture resin and denture lining material.

Material and Methods

Bar-shaped (75×10×10 mm) and square-shaped (10×10×3 mm) specimens were manufactured using heat-polymerized (HT) (VIPICRIL Plus) and 3D-printed (3D) (Prizma 3D Bio Denture) denture base resin. The bar specimens were sectioned, removing 3 mm from the center to facilitate the insertion of the denture lining material (Ufi Gel SC). Specimens were subjected to three surface treatments (n=15): no treatment (CT), immersion in monomer for 180 seconds (M), and airborne-particle abrasion oxide with 50 µm aluminum oxide (AP). The tensile bond strength was measured at a rate of 5mm/min before and after subjecting the specimens to thermocycling (10 000 cycles). The square-shaped specimens were used to assess average surface roughness (Ra) and wettability (°). Data analysis was performed using a 3-way ANOVA with Tukey's post-test (P<.05).

Results

The treatment of the 3D-printed denture base resin (1.200±0.486) with AP made the bond strength to the denture lining material similar to HT denture base resin (1.314±0.249), without the negative impact of aging. In contrast, M treatment increased the bond strength of both resins to the denture lining material (HT: 2.076±0.463; 3D: 1.534±0.484). Treatment with M provided a lower contact angle for the 3D and HT denture base resin, while the HT denture base resin presented a greater surface roughness for M and AP, compared to 3D.

Conclusions

The 3D-printed denture base resin should undergo immersion in monomer treatment to enhance its bond strength with the denture lining material. Key words:Denture lining material, Complete denture, Manufactured material, Denture base resin, Bond strength.

Cross-Cultural Adaptation of The Indonesian Version Functional Assessment of Denture Instrument as a Measuring Tool for Complete Denture Functional Quality

OBJECTIVE

 Making good quality dentures is necessary to avoid patients' discomfort when adapting to new dentures. Several studies regarding the assessment of the quality of dentures have been carried out in many other countries, such as using the Functional Assessment of Dentures (FAD) by Anastassiadou. However, studies have yet to be conducted in Indonesia. This study aims to obtain a valid and reliable instrument to measure the quality of complete dentures (CDs). This study also aims to find out whether the functional quality of a CD measured with the Indonesian version of the FAD Instrument (PFGT) can affect patient satisfaction in receiving CD treatment (measured with Indonesian version of Patient's Denture Assessment [PDA-Id]) and to find contributing factors to the functional quality of a CD.

MATERIALS AND METHODS

 The study was conducted in two stages. The first stage was a qualitative study using cross-cultural adaptation methods and focus group discussions with experts. The second stage was a quantitative test with a total of 40 subjects for statistical analysis in the form of a kappa test, test-retest, Kuder-Richardson (KR) 20, and a correlation test between PDA-Id and PFG. Multivariate analysis was done to analyze contributing factors to the functional quality of CD.

RESULTS

 The final instrument was obtained from the qualitative test, which was tested for content and face validation. The interrater kappa test result of 0.828 shows an almost perfect agreement. The results of the intrarater test-retest (0.564; p > 0.05; intraclass correlation coefficient 0.889) showed excellent instrument stability. The results of the internal consistency test with Kuder-Richardson 20 (1.08; KR > 1) showed good internal consistency. The correlation test results between PFGT and PDA-Id (0.044; p < 0.05) showed a positive correlation. Multivariate analysis showed a relationship between the quality of the CD, the length of time the CD was used, and the patient's satisfaction with CD treatment.

CONCLUSION

 The PFGT instrument is considered a valid and reliable tool to measure the functional quality of a denture that can distinguish between good and bad quality.

Influence of new complete dentures on the touch perception threshold and quality of life of edentulous patients

OBJECTIVE

To evaluate the touch perception threshold of the alveolar mucosa and quality of life of edentulous patients before (T0) and 30 days after (T1) the insertion of new complete dentures.

BACKGROUND

Touch perception is important so that edentulous patients can detect the position of complete dentures in their mouth.

MATERIALS AND METHODS

This study included 32 complete denture wearers with good oral and systemic health and no temporomandibular disorders for at least 5 years. At each time point (T0 and T1), two tests were performed (touch perception threshold and quality-of-life scale). The touch perception threshold (Von Frey or Semmes-Weinstein test) was assessed using nylon monofilaments on the regions of the alveolar mucosa of the maxilla and mandible. The Oral Health Impact Profile for edentulous individuals (OHIP-EDENT) was administered to evaluate oral health-related quality of life.

RESULTS

In the maxilla and mandible, the touch perception thresholds for all regions of the alveolar mucosa were significantly lower at T1 than at T0. The OHIP-EDENT mean scores showed that the overall quality of life was significantly better at T1 (3.6) than at T0 (4.7), and a significant improvement in quality of life was observed in all domains of the OHIP-EDENT at T1. For touch perception threshold, effect sizes ranged from 0.4 to 0.8; and for quality of life, effect sizes ranged from 0.4 to 1.0.

CONCLUSIONS

New complete dentures reduced the touch perception threshold of the alveolar mucosa of both edentulous arches and improved individuals' quality of life.

In vitro evaluation of shape-memory hydrogels for removable dental prostheses and optimization of phase-transition temperature for intraoral use

STATEMENT OF PROBLEM

Removable dental prostheses require periodic relining with the loss of intaglio surface fit because of mucosal shape changes over time. Therefore, a new material with high adaptability to tissue changes over time would be beneficial.

PURPOSE

This study focused on a shape-memory gel (SMG) that softens when heated, retains its shape when cooled, and returns to its original shape when reheated. The purpose was to optimize SMG for intraoral use by controlling the ratio of 2 acrylate monomers and to evaluate the changes in the shape memory and physical properties of SMG with temperature and to evaluate biocompatibility.

MATERIAL AND METHODS

SMG specimens were synthesized using the following mixing ratios of 2 monomers, docosyl acrylate (DA) and stearyl acrylate (SA): 0:100, 25:75, 50:50, 75:25, and 100:0. SMG specimens were photopolymerized using a fluorescent light-polymerizing unit. To evaluate shape memory as a function of temperature, permanent deformation was measured based on the standardized compression set test for thermoplastic rubber. For evaluation of the physical properties and cytotoxicity, a 3-dimensionally printed denture base material was used as the control material. All assessments were compared between the groups by using 1-way analysis of variance followed by the Tukey-Kramer multiple comparison test (α=.05).

RESULTS

SMGs with a higher amount of DA maintained their compressed shape at room and intraoral temperatures. However, the SMG matrices softened and recovered their original shapes above 60 °C. SMGs showed Shore A hardness equivalent to that of the denture-base polymer material at intraoral temperatures because of the high phase-transition temperature. The low water solubility of SMGs supported the biocompatibility test results.

CONCLUSIONS

SMG, in which the phase-transition temperature was controlled by mixing acrylate monomers with different melting points, exhibited shape memory in the intraoral environment. The results indicate the feasibility of applying SMG for the fabrication of removable dental prostheses because of its high adaptability to tissue changes over time and biocompatibility.

The Effect of Exposure to Candida Albicans Suspension on the Properties of Silicone Dental Soft Lining Material

While functioning in the oral cavity, denture soft linings (SL) are exposed to contact with the microbiota. Dentures can offer perfect conditions for the multiplication of pathogenic yeast-like fungi, resulting in rapid colonisation of the surface of the materials used. In vitro experiments have also shown that yeast may penetrate SL. This may lead to changes in their initially beneficial functional properties. The aim of this work was to investigate the effect of three months of exposure to a Candida albicans suspension on the mechanical properties of SL material and its bond strength to the denture base polymer, and to additionally verify previous reports of penetration using a different methodology. Specimens of the SL material used were incubated for 30, 60 and 90 days in a suspension of Candida albicans strain (ATCC 10231). Their shore A hardness, tensile strength, and bond strength to acrylic resin were tested. The colonization of the surface and penetration on fractured specimens were analysed with scanning electron and inverted fluorescence microscopes. Exposure to yeast did not affect the mechanical properties. The surfaces of the samples were colonised, especially in crystallized structures of the medium; however, the penetration of hyphae and blastospores into the material was not observed.

Halitosis and Pain Threshold of Peri-Implant Tissues: An Observational Cohort Study

In this study, we aimed to evaluate the halitosis and pain threshold of the peri-implant soft tissues in individuals rehabilitated with implant-supported prostheses. Forty-eight subjects were divided into four groups (n = 12) according to their prosthetic rehabilitation: single-tooth fixed prosthesis, multi-tooth fixed prosthesis, overdentures, and the Brånemark protocol. Halitosis was measured using a halimeter, whereas the pain threshold was measured using Von Frey monofilaments. Measurements were taken before (t0) and 30 days after (t1) placement of healing caps, and at the time of (t2) and 30 days after (t3) prosthetic placement. Halitosis data were analyzed using the chi-square test and Bonferroni correction (p < 0.05). Two-way ANOVA and Tukey's test (p < 0.05) were used to analyze pain threshold data. We noted an association between halitosis and time for the Brånemark protocol [X2(6) = 18.471; p = 0.005] and overdenture groups [X2(6) = 17.732; p = 0.007], and between halitosis and type of prosthesis only at t0 [X2(6) = 12.894; p = 0.045]. The interaction between time and the type of prosthesis significantly interfered with the mean pain threshold values (p = 0.001). At most time points, the majority of participants in each group had clinically unacceptable halitosis. After 30 days of using the prostheses, the overdenture group had a lower pain threshold compared to the Brånemark protocol group.

Tensile Bond Strength between Different Denture Base Materials and Soft Denture Liners

(1) Background: Various materials are available for CAD-CAM denture base fabrication, for both additive and subtractive manufacturing. However, little has been reported on bond strength to soft denture liners. Therefore, the aim of this study was to investigate tensile bond strength, comparing between different denture base materials and soft denture liners. (2) Methods: Seven different materials were used for denture base fabrication: one heat-polymerized polymethyl methacrylate, three materials for subtractive manufacturing, two materials for additive manufacturing and one polyamide. Two materials were used for soft denture lining: one silicone-based and one acrylate-based. The study was conducted according to the specification ISO No. 10139-2:2016, and the type of failure was determined. The Kruskal-Wallis test with Dunn's post hoc test was used to analyse the values of tensile bond strength, and Fisher's exact test was used to analyse the type of failure. p Values < 0.05 were considered statistically significant. (3) Results: The tensile bond strength values were not statistically significantly different combining all the materials used for denture base fabrication with the acrylate-based soft denture liner (p > 0.05), and the average values ranged between 0.19 and 0.25 Mpa. The tensile bond strength values of the different denture base materials and silicone-based denture liner were statistically significantly different (p < 0.05), and the average values ranged between 1.49 and 3.07 Mpa. The type of failure was predominantly adhesive between polyamide and both additive-manufactured denture base materials in combination with the acrylate-based soft liner (p < 0.05). (4) Conclusions: The use of digital technologies in denture base fabrication can have an influence on different tensile bond strength values for soft denture liners, with different types of failure when compared with heat-cured PMMA. Similar tensile bond strength values were found between the acrylate-based soft denture liner and denture base materials. Significant differences in tensile bond strength values were found between the silicone-based soft denture liner and denture base materials, where the additive-manufactured and polyamide denture base materials showed lower values than heat-cured PMMA and subtractive-manufactured denture base materials.

CAD-CAM complete denture resins: Effect of relining on the shear bond strength

OBJECTIVES

The aim of this study was to compare the shear bond strength of relined CAD-CAM complete removable dental prosthesis (CRDP) resins with conventional heat-polymerized polymethylmethacrylate (PMMA) resin.

METHODS

A total of 96 resin specimens in identical dimensions of 10 mm × 10 mm × 11 mm were fabricated for four study groups [#1- Conventional heat-polymerized group: n=24 (ProBase); #2- Milled#1: n=24 (Ivobase); #3- Milled#2: n=24 (Ivotion); #4- 3D-printed: n=24, (NextDent Denture 3D+)]. Twelve specimens in each group were sectioned in the middle to produce a 3 mm defect and then were relined using a conventional denture relining material. All specimens underwent thermocycling (5-55°C) for 10,000 cycles. The shear bond tests were carried out in a universal testing machine. One-way ANOVA and Tukey's test were used for statistical analysis (p<0.05). The two-parameter Weibull distribution values were calculated.

RESULTS

Relined 3D-printed specimens had a significantly lower shear bond strength when compared with conventional (p=0.0003) and milled groups (Milled#1: p=0.0004; Milled#2: p<0.0001). There were no differences in the shear bond strengths between the milled and conventional groups. Weibull distribution presented the highest shape value for the non-relined Milled#1 (22.83) group and the lowest values for the 3D-printed relined group (4.001).

CONCLUSION

The findings of this study conclude that the shear bond strength of the conventionally-relined 3D-printed resins used for fabricating CRDPs was inferior to the shear bond strength of conventionally-relined resins employed for manufacturing CRDPs using CAD-CAM milling and conventional heat-polymerization techniques.

CLINICAL SIGNIFICANCE

When considering 3D-printing for the fabrication of CRDPs, it is recommended to employ it in clinical situations where a frequent need for denture relining is not expected.

The Problem of Halitosis in Prosthetic Dentistry, and New Approaches to Its Treatment: A Literature Review

The aim of this work is a review of recent scientific literature about intra-oral halitosis among patients using dentures. Halitosis is a condition in which an unpleasant smell comes out of the oral cavity, which is caused mainly by volatile sulfur and non-sulfured compounds. The etiology of halitosis may be intra- or extra-oral; in most patients, however, it is due to the activity of microorganisms in the oral cavity. The problem of the occurrence of intra-oral halitosis has accompanied patients for many years. In dental prosthetics, the problem of halitosis occurs in patients using removable or fixed dentures. In both cases, new niches for the development of microorganisms may be created, including those related to intra-oral halitosis. It should be noted that dentures—both fixed and removable—are a foreign body placed in the patient’s oral cavity which, in case of insufficient hygiene, may constitute a reservoir of microorganisms, causing this unpleasant condition. Conventional treatment of intraoral halitosis reduces microbial activity via chemical and/or mechanical action. Currently, the search for new strategies in the treatment of halitosis is in progress. One idea is to use photodynamic therapy, while another is to modify poly(methyl methacrylate) (PMMA) with silver and graphene nanoparticles. Additionally, attempts have been made to combine those two methods. Another unconventional method of treating halitosis is the use of probiotics.