Cytotoxicity of denture base and hard chairside reline materials: a systematic review

Statement of problem. Adverse reactions to the materials used for the fabrication and reline of removable denture bases have been observed.Purpose. The purpose of this study was to systematically review the published literature on the cytotoxicity of denture base and hard reline materials.Material and methods. MEDLINE via PubMed, Google Scholar, and Scopus databases for the period January 1979 to December 2009 were searched with the following key words: (biocompatibility OR cytotoxic* OR allergy OR burning mouth OR cell culture techniques) and (acrylic resins OR denture OR monomer OR relin* OR denture liners). The inclusion criteria included in vitro studies using either animal or human cells, in which the cytotoxicity of the denture base and hard chairside reline resins was tested. Studies of resilient lining materials and those that evaluated other parameters such as genotoxicity and mutagenicity were excluded. Articles published in the English language and in peer-reviewed journals focusing on the cytotoxicity of these materials were reviewed.Results. A total of 1443 articles were identified through the search. From these, 20 studies were judged to meet the selection criteria and were included in the review. In the majority of the studies, continuous cell lines were exposed to eluates of specimens made from the materials, and mitochondrial activity was used to estimate cell viability. The tested acrylic resins were grouped according to 5 major categories: (1) heat-polymerized; (2) microwave-polymerized; (3) autopolymerizing; (4) light-polymerized; and (5) hard chairside reliners.Conclusions. This review provided some evidence that the heat-polymerized resins showed lower cytotoxic effects than autopolymerizing denture base acrylic resins and light or dual polymerized reline resins. However, because of the large number of variables in the reviewed literature, a definitive conclusion could not be drawn. (J Prosthet Dent 2012;107:114-127)

Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation

Background: This study evaluated the effect of disinfection by immersion and microwave irradiation on the roughness of one denture base resin (Lucitone-L) and five relining materials, three hard (Tokuyama Rebase II-TR, New Truliner-NT, Ufigel Hard-UH) and two resilient (Trusoft-T, Sofreliner-S).Methods: Fifty specimens were made and divided into groups: CL2 specimens were brushed with 4% chlorhexidine (1 min), immersed in the same solution (10 min) and immersed in water (3 min); MW2 specimens were immersed in water and microwave irradiated (650W; 6 min); CL2 and MW2 specimens were disinfected twice; CL7 and MW7 specimens were submitted to seven cycles using chlorhexidine or microwave irradiation, respectively; W specimens were not disinfected and remained in water (37 degrees C; 7 days).Results: Results were statistically analysed (p = 0.05) and revealed that, at baseline, the highest mean value was observed for T (p < 0.001). Material NT showed increase in roughness after the first (p = 0.003), second (p = 0.001), seventh (p = 0.000) cycles of microwave disinfection and after 7 days of immersion in water (p = 0.033).Conclusions: Resilient liner S presented significant increase in roughness after the second cycle of disinfection with chlorhexidine (p = 0.003). Material T exhibited significantly decreased roughness in group W (p = 0.010), while microwaving produced severe alterations on its surface.

Effect of reline material and denture base surface treatment on the impact strength of a denture base acrylic resin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of incorporation of 2-tert-butylaminoethyl methacrylate on flexural strength of a denture base acrylic resin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of Microwave Disinfection on the Linear Dimensional Stability of Complete Dentures: A Clinical Study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of oral hygiene education and motivation on removable partial denture wearers: longitudinal study

The purpose of this study was to determine the effect of two different preventive oral hygiene education and motivation programmes on the plaque and gingival index, as well as denture hygiene of patients provided with removable partial denture (RPD) during a 12-month follow-up.A total of 53 partially edentulous patients were recruited for this study. The presence or absence of plaque and gingival bleeding by gentle probing was scored on all tooth surfaces at the preliminary visit. The plaque and gingival indexes were measured using the Loe index. Following treatment, the patients were randomly divided into three groups. In Control Group I, subjects were instructed to continue their personal oral hygiene routine. In Group II, participants were given verbal instructions and a self-educational manual on oral hygiene without illustrations. In Group III, oral hygiene guidance was delivered using a combination of verbal instructions and a self-teaching manual. To evaluate the effect of the different modes of instruction, the presence or absence of plaque and gingival bleeding was scored on all tooth surfaces (day zero examination) and re-examined 7, 15 and 30 days, 3, 6 and 12 months following RPD placement. The state of denture hygiene was evaluated 7, 15 and 30 days and 3, 6 and 12 months following rehabilitation. Parametric statistics was applied to dental plaque and gingival indexes. For accumulation of plaque and calculus on the RPD, non-parametric statistic was applied.The frequency of plaque found during the preliminary visit was higher than that found in the other periods. With regard to gingival index, significant difference was found between the preliminary visit examination and other periods. There was a significant difference in the plaque accumulation on the denture surface between groups I and III.The different methods of oral hygiene instruction used in this study indicate that the type of education was not of significant importance.

Influence of surface treatments on the flexural strength of denture base repair

Objective: The purpose of this study was to evaluate the flexural strength of repairs made with autopolymerising acrylic resin after different treatments of joint surfaces.Material and Methods: Fifty rectangular specimens were made with heat-polymerised acrylic resin and 40 were repaired with autopolymerising acrylic resin following joint surface treatments: group 1 (intact specimens), group 2 (chemical treatment: wetting with methyl-methacrylate for 180 s), group 3 (abraded with silicon carbide paper), group 4 (abraded and wetting with methyl-methacrylate for 180 s) and group 5 (without surface treatment). The flexural strength was measured by a three-point bending test using a universal testing machine with a 100 Kgf load cell in the centre of repair at 5 mm/min cross-head speed. All data were analysed using one-way ANOVA and Tukey HSD test for multiple comparisons (p < 0.05).Results: Among repaired specimens, groups 2 and 4 had 66.53 +/- 3.4 and 69.38 +/- 1.8 MPa mean values and were similar. These groups had superior flexural strength than groups 3 and 5 that were similar and had 54.11 +/- 3.4 and 51.24 +/- 2.8 MPa mean values, respectively. Group 1 had a mean value of 108.30 +/- 2.8 MPa being the highest result.Conclusion: It can be concluded that the treatment of the joint surfaces with methyl-methacrylate increases the flexural strength of denture base repairs, although the strength is still lower than that observed for the intact denture base resin. Abrasion with sandpaper was not able to influence the flexural strength of repaired denture bases.

Effect of microwave disinfection on the surface roughness of three denture base resins after tooth brushing

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of disinfection by microwave irradiation on the strength of intact and relined denture bases and the water sorption and solubility of denture base and reline materials

This study evaluated the influence of microwave disinfection on the strength of intact and relined denture bases. Water sorption and solubility were also evaluated. A heat-polymerized acrylic resin (Lucitone 550) was used to construct 4-mm-thick (n = 40) and 2-mm-thick (n = 160) denture bases. Denture bases (2mm) were relined with an autopolymerizing resin (Tokuso Rebase Fast, Ufi Gel Hard, Kooliner, or New Truliner). Specimens were divided into four groups (n = 10): without treatment, one or seven cycles of microwave disinfection (650 W for 6 min), and water storage at 37 degrees C for 7 days. Specimens were vertically loaded (5 mm/min) until failure. Disc-shaped specimens (50 min x 0.5 mm) were fabricated (n = 10) to evaluate water sorption and solubility. Data on maximum fracture load (N), deflection (%), and solubility (%) were analyzed by two-way analysis of variance and Student-Newman-Keuls tests (alpha = 0.05). One cycle of microwave disinfection decreased the deflection at fracture and fracture energy of Tokuso Rebase Fast and New Truliner specimens. The strength of denture bases microwaved daily for 7 days was similar to the strength of those immersed in water for 7 days. Microwave disinfection increased the water sorption of all materials and affected the solubility of the reline materials. (C) 2007 Wiley Periodicals, Inc.

Effectiveness of Photodynamic Therapy for the Inactivation of Candida spp. on Dentures: In Vitro Study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Candida spp. prevalence in well controlled type 2 diabetic patients with denture stomatitis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Denture stomatitis treated with photodynamic therapy: five cases

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Color stability of relined dentures after chemical disinfection. A randomised clinical trial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anatomic study of the mandibular foramen, lingula and antilingula in dry mandibles, and its statistical relationship between the true lingula and the antilingula

The authors verified the anatomical location of the mandibular foramen, lingula and antilingula in dry mandibles, aiming to obtain information that could be used when performing mandibular osteotomies. Forty-four mandibles (88 sides) were evaluated. The distances were measured using a sliding calliper, with the mandibles fixed in a reproducible position. Results showed that the mandibular foramen is on average 5.82 mm below the lingula. Regarding the statistical comparison between the mandibular foramen entrance and the anti lingula position, there is no correlation between the position of those two structures in the studied sample. The mandibular foramen is slightly posterior in relation to the centre of the ramus. The lingula is an important anatomic landmark for ramus surgery, and for determining the distance to the mandibular foramen entrance. The use of the antilingula as a landmark for the position of the vertical ramus osteotomy is not recommended.

Location of the mandibular foramen according to the amount of dental alveoli

The aim of this study was to analyze the anatomotopographic location of the mandibular foramen in the right and left ramus, and to verify the influence of the amount of dental alveoli on the foramen position. Thirty-five adult dry human mandibles of Araraquara Dental School, UNESP - São Paulo State University were assessed, with or without dental alveoli. Measurements were obtained, using a ruler and a digital caliper. The following distances were measured: Fl - distance between the lowest point of the mandibular incisure and the mandibular foramen (F point); FB - distance between the mandibular base and F point; FP - distance between the posterior margin of the ramus and F point; FA - distance between the anterior margin of the ramus and F point; FT - distance between the apex of the retromolar trigone and F point. The Mann-Whitney test was used to compare each measurement according to hemi-arch, and the Kruskal-Wallis test was used to analyze the influence of the presence of alveoli on the measures. For multiple comparison, Dunn's method was used. There was no statistically significant difference in the location of the mandibular foramen when compared to the right and left hemi-arches. The amount of dental alveoli influenced, significantly, only on FA and FP distances. Thus, it was concluded that the right and left mandibular ramus showed symmetry in the location of the mandibular foramen, and the amount of alveoli influenced on the distances of the anterior and posterior margins of the mandibular rams, in relation to the mandibular foramen.