Randomized controlled trial to investigate how acrylic‐based resilient liner affects on masticatory ability of complete denture wearers

Summary The aim of this study was to determine the effects of an acrylic‐based resilient liner (ARL) on masticatory ability by verifying the null hypothesis that masticatory performance and mandibular movements do not differ between people who wear mandibular complete dentures with ARL and those who wear complete dentures with conventional acrylic resin (CAR). From April 2004 to July 2006, we conducted a randomized controlled trial study at two centres. After written informed consent was obtained from 74 edentulous patients, they were randomly allocated to either the ARL group or CAR group. Masticatory performance and mandibular movement at the lower incisal point during chewing were measured as the outcomes. We did not observe significant differences in both outcomes between the groups. The chewing cycles were significantly different during the initial, middle, and final phases of mastication. Within the limitations of the current study, the results indicate that the acrylic‐based resilient denture liners used have no clinical impact on the masticatory ability of complete denture wearers.     

Randomized controlled clinical trial for verifying the effect of silicone-based resilient denture liner on the masticatory function of complete denture wearers

PURPOSE: The purpose of this study was to investigate whether application of permanent silicone-based resilient denture liner (SR) to mandibular complete dentures significantly improves patients' masticatory ability compared to conventional heat-activated acrylic resin (AR). MATERIALS AND METHODS: Twenty-eight edentulous patients were randomly placed into 1 of 2 crossover groups (AR-SR/SR-AR) by using a random permuted block within strata method. The AR-SR group received AR denture treatments followed by SR denture treatments. The SR-AR group received treatments in the reverse sequence. The outcomes were classified by matiscatory performance, mandibular movement, electromyographic activity, and maximum occlusal force. RESULTS: No significant differences were observed in any of the baseline characteristic measurements between groups. SR denture wearers exhibited significantly higher masticatory performance than AR denture wearers. SR denture wearers exhibited a longer early-stage occluding period than AR denture wearers. There were no differences in electromyographic activity between the AR and SR groups. There were no significant differences in maximum occlusal force between the AR and SR groups. CONCLUSION: This study showed that the application of SR to mandibular complete dentures resulted in significant improvements to the patients' masticatory ability compared to AR.     

Variation in blood flow of supporting tissue during use of mandibular complete dentures with hard acrylic resin base and soft relining: a preliminary study

PURPOSE: This study investigated the influence of hard and resilient polymerized acrylic resin base materials on the blood flow of the supporting underlying mucosa of mandibular denture wearers during different denture-wearing periods. MATERIALS AND METHODS: Measurements were carried out on 20 complete denture wearers, 10 with hard bases and 10 with soft ones. The mucosal blood flow underlying the dentures was measured bilaterally in the canine and molar regions using a laser Doppler flowmeter. Baseline measurements were performed before denture wearing and after the dentures were worn for 1 week, 1 month, 3 months, and 6 months. RESULTS: Mean blood flow to the mucosa after 1 week was significantly lower in the measured regions than that obtained before the dentures were worn. Blood flow in the canine region returned to almost normal levels 6 months after beginning to wear complete dentures. However, blood flow in the molar region of the denture wearers in the hard base group increased after 6 months, whereas blood flow values did not return to the levels recorded before denture insertion in the soft lining group. CONCLUSION: It appears that wearing dentures hinders blood flow to denture-supporting tissues, even when soft liners are used.     

Effect of viscoelastic properties of resilient denture liners on pressures under dentures

In order to evaluate the influence of viscoelastic properties of resilient denture liners on the pressures under dentures, a series of creep and stress relaxation tests were carried out using a simplified mandibular edentulous model and denture model. Two diaphragm pressure sensors were attached to the edentulous model so that they contacted the residual ridge and the buccal slope. The results may be summarized as follows: (i) The use of resilient denture liners is effective for stress relief under dentures. (ii) The thickness increase of each denture liners causes the effect of stress relaxation. (iii) The material exhibited viscoelastic behaviour after applying the stress and has the ability to distribute stress or stress relaxation. It is important to understand the viscoelastic behaviours of each resilient denture liner and choose the material according to the clinical situation. The information obtained should be useful to clinicians when they select materials for their patients.     

义齿黏附剂与线性殆在牙槽嵴重度吸收无牙颌患者中的应用

目的：评价义齿黏附剂和线性胎在牙槽嵴吸收严重的无牙颌患者全口义齿修复中的应用效果。方法：选择15例牙槽嵴吸收严重的无牙颌患者,为每位患者制作解剖式骀和线性胎2副全口义齿,3个月后更换使用。每副义齿于戴用3个月时检测其使用义齿黏附剂前后的咀嚼效率,并采用满意度问卷调查获取患者的主观评价。结果：使用义齿黏附剂后,线性胎和解剖式胎全口义齿的咀嚼效率均较使用前得到改善（P〈0．05,P〈0．01）。义齿黏附剂使用前后,两种骀型全口义齿的咀嚼效率间差异无统计学意义（P〉0．05）。义齿黏附剂使用前,线性骀全口义齿的固位稳定和舒适程度满意度高于解剖式骀全口义齿（P〈0．05,P〈0．01）;使用义齿黏附剂后,两种胎型全口义齿的固位稳定、咀嚼功能和舒适程度满意度均有显著性提高（P〈0.01）。结论：对牙槽嵴吸收严重的无牙颌患者,应用线性骀全口义齿和义齿黏附剂均可改善义齿的治疗效果。     

Randomized controlled clinical trial on satisfaction with resilient denture liners among edentulous patients

PURPOSE: The purpose of this study was to measure patients' satisfaction and their preference between mandibular dentures with permanent silicone-based resilient denture liner (SR) and conventional heat-activated acrylic resin (AR), both opposed by acrylic resin-based maxillary complete dentures. MATERIALS AND METHODS: Twenty-eight edentulous patients who had fulfilled selection criteria and provided informed consent were enrolled in this trial. Subjects were allocated randomly to either arm of cross-over groups (AR-SR/SR-AR), stratified by gender, using a random permuted block within the strata method. The AR-SR group received AR denture treatment followed by SR denture treatment. The SR-AR group received treatment in the reverse sequence. The primary outcome was patient satisfaction measured on 100-mm VAS, analyzed by two-way ANOVA and the Bonferroni multiple comparison as a post hoc test. The secondary outcome was patients' preference, evaluated by chi-square goodness-of-fit test. An intention-to-treat analysis was performed. RESULTS: Twenty-five subjects were enrolled in the analysis. There were no significant differences between AR and SR dentures 1, 2, and 3 months after the completion of control. Eighteen of 25 patients preferred SR dentures. CONCLUSION: Although there were no significant differences in patient satisfaction ratings between the two types of dentures, a significant majority of patients preferred those with a resilient denture liner.     

The effects of silicone-based resilient denture liners on pain: A randomized controlled trial

PurposeThis randomized controlled trial aimed to study the effects of lining mandibular complete dentures with silicone-based resilient denture liners, especially with respect to sensation.MethodsThe trial included completely edentulous patients who were willing to fabricate new set of complete denture. A random permuted block method (block size: 4) was used to assign participants to one of the following groups: mandibular conventional denture (CD) group or mandibular denture with resilient denture liner (RD) group. The outcomes were evaluated using both, objective measures (current perception threshold (CPT) and pain threshold (PT)) for external stimuli measured using the Neurometer CPT® and subjective measures (physical pain and psychological discomfort measured using the Japanese version of Oral Health Impact Profile for Edentulous patients—OHIP-EDENT-J). The outcomes were measured twice, at immediately after completion of denture adjustments (first measurement), and 3 months after the completion of denture adjustments (second measurement). All outcomes were analyzed using the Student t-test. A p-value of <0.05 was considered statistically significant.ResultsCPT was significantly higher with RD than CD only at second measurement with frequency level of 2000 Hz and 5 Hz. The pain thresholds were significantly higher in the RD group than the CD group. The physical pain and psychological discomfort scores were significantly lower in the RD group than in the CD group.ConclusionThis study concludes that edentulous patients wearing mandibular complete dentures with silicone-based resilient denture liners dull perception mandibular ridge mucosa and felt less pain than those without the liners.     

Clinical evaluation of resilient denture liners. Part 2: candida count and speciation

PURPOSE: The purpose of this study was to count and to speciate Candida isolated from 2 resilient denture liners, Molloplast-B and MPDS-SL. MATERIALS AND METHODS: A group of 20 patients each had 1 maxillary denture and 2 mandibular dentures fabricated. One mandibular denture was lined with Molloplast-B, and 1 was lined with MPDS-SL. Each denture was used for 3 months. At the end of the 3-month period, the mandibular denture was surrendered, and a 5 x 5-mm circular resilient liner sample was obtained from the tissue surface of the lingual flange. Samples were processed, and Candida was isolated and counted. Speciation of Candida was performed using CHROMagar Candida and API 20C AUX strips. RESULTS: Molloplast-B had, on average, 5 times as many CFU/sample as MPDSL-SL, but this difference was not significant (p = 0.26). A sign test gave a similar nonsignificant trend (p = 0.057). CHROMagar identified several Candida species, and confirmation was made using API 20C AUX strips. One patient was lost to follow-up. Of 19 Molloplast-B samples, 7 had no growth, 4 grew C. albicans, 3 grew C. parapsilosis, 2 grew C. glabrata, 1 grew C. tropicalis, 2 grew a Trichosporon spp., and 2 grew a nonidentifiable colony. The analogous counts for 19 MPDS-SL samples were 10, 4, 1, 3, 0, 1, and 1 (p = 0.45 for culture positively, exact McNemar test). CONCLUSIONS: Candida growth on Molloplast-B was not significantly different from growth on MPDS-SL. Several yeast species were cultured from each material. The rates of culture-positive testing did not differ between the 2 resilient denture liners.     

Clinical Applications of a Polyphosphazene-Based Resilient Denture Liner

The use of resilient denture liners provides an invaluable modality in removable prosthodontic treatment. Treatment of atrophic mandibles, preoperative and postoperative soft tissue management, and retention of removable prosthesis are a few applications of these materials. This article describes the clinical application of a polyphosphazene-based liner (Novus, Hygenic Corp, Dayton, OH) as a denture liner and retentive material in conventional and implant overdenture rehabilitation.     

软衬基托全口义齿的固位与力研究

目的 研究比较软衬基托全口义齿与传统全口义齿的固位力和（牙合）力,以评价弹性软托全口义齿的治疗效果,以期为临床的软衬治疗提供理论依据。方法 选择10名牙槽嵴欠丰满的全口义齿患者为受试对象,以SoftReverse软衬材制作软衬义齿基托,分别测试他们戴软衬基托和传统基托义齿时的固位力及（牙合）力,进行自身对照分析。结果 所有患者戴弹性软基托义齿时的固位力和（牙合）力均明显高于戴传统基托时的相对应测试值。结论 从咀嚼功能和戴牙舒适的角度上说,弹性软衬基托全口义齿明显地优于传统基托全口义齿。     

Randomized controlled clinical trial on satisfaction with resilient denture liners among edentulous patients

Purpose

The purpose of this study was to measure patients' satisfaction and their preference between mandibular dentures with permanent silicone-based resilient denture liner (SR) and conventional heat-activated acrylic resin (AR), both opposed by acrylic resin-based maxillary complete dentures.

Materials and Methods

Twenty-eight edentulous patients who had fulfilled selection criteria and provided informed consent were enrolled in this trial. Subjects were allocated randomly to either arm of cross-over groups (AR-SR/SR-AR), stratified by gender, using a random permuted block within the strata method. The AR-SR group received AR denture treatment followed by SR denture treatment. The SR-AR group received treatment in the reverse sequence. The primary outcome was patient satisfaction measured on 100-mm VAS, analyzed by two-way ANOVA and the Bonferroni multiple comparison as a post hoc test. The secondary outcome was patients' preference, evaluated by chi-square goodness-of-fit test. An intention-to-treat analysis was performed.

Results

Twenty-five subjects were enrolled in the analysis. There were no significant differences between AR and SR dentures 1, 2, and 3 months after the completion of control. Eighteen of 25 patients preferred SR dentures.

Conclusion

Although there were no significant differences in patient satisfaction ratings between the two types of dentures, a significant majority of patients preferred those with a resilient denture liner.—Reprinted with permission of Quintessence Publishing.     

Setting and stress relaxation behavior of resilient denture liners

Statement of problem. Resilient denture liners are widely used for the patients who are not comfortable with correctly made conventional hard-based dentures because of thin and relatively nonresilient mucosa or severe alveolar resorption. There are several materials used for denture liners and the efficacy in their use is influenced by their viscoelastic properties. Purpose. This study evaluated the setting behavior and viscoelastic properties of various types of resilient denture liners and the changes in viscoelasticity with the passage of time. Material and methods. Four types of resilient denture liners were used. Setting behavior of 5 autopolymerizing materials was evaluated with an oscillating rheometer. Stress relaxation tests were conducted to evaluate the viscoelastic properties of 9 materials and changes that occurred over time by means of Maxwell model analogies. Results. Significant differences were found in the setting behavior of the autopolymerizing materials. The acrylic resin and fluoroethylene materials demonstrated viscoelastic properties and the silicone and polyolephin materials were found to be elastic. The acrylic resin materials exhibited the greatest changes in viscoelastic properties over time when compared with silicone, polyolephin, and fluoroethylene materials. Conclusions. The results suggest that it is important to select denture liner materials according to clinical situations because of the wide ranges of setting behavior, viscoelastic properties, and durability over time.(J Prosthet Dent 1998;80:714-22.)     

A comparison of patient's satisfaction between complete and partial removable denture wearers

OBJECTIVES: The aim of this study was to compare satisfaction between complete denture (CD) and Kennedy Class I removable partial denture (RPD) wearers. MATERIALS AND METHODS: A total of 156 CD and 112 RPD wearers took a part in this study. From the primary group of the examined patients, only those whose RPDs and CDs were assessed as excellent or very good by the dentist, took a part in this study. Patients graded satisfaction of their dentures by using an analogue scale from 1 to 5 (1=unsatisfactory; 5=excellent). RESULTS: Both CD and RPD wearers were mostly satisfied with their dentures (the distribution of the scores of the patients' assessments was skewed towards the highest scores; more than half of the patients scored all the examined variables to the best score category). Complete Denture wearers were significantly more satisfied with chewing, speech and retention of maxillary denture than RPD wearers (P<0.05). Removable partial denture wearers were significantly more satisfied with the retention and the comfort of wearing mandibular denture (P<0.05). There was no significant difference between CD and RPD wearers for general satisfaction with their dentures, aesthetics and comfort of wearing maxillary denture (P>0.05; N.S.). CONCLUSIONS: A majority of CD and RPD wearers were satisfied with the dentures. CD wearers were more satisfied with speech, chewing and retention of maxillary denture, while RPD wearers were more satisfied with the retention and the comfort of wearing mandibular denture. Different groups of denture wearers have to make significant, but different adjustments to wear their dentures successfully.     

Effect of Complete Dentures on Craniofacial Growth of an Ectodermal Dysplasia Patient: A Clinical Report

The aim of this clinical report was to observe the effect of complete dentures on craniofacial growth and development of an ectodermal dysplasia (ED) patient. A complete anodontia patient diagnosed with ED was successfully rehabilitated with conventional complete dentures at the ages of 5, 8, and 10 years. Three sets of complete dentures were made with age‐appropriate denture teeth and a bilaterally balanced lingualized occlusal scheme. Periodic follow‐up and adjustment when needed was done to maintain proper oral function and esthetics. Serial cephalometric analysis exhibited a marked restriction of forward growth at the anterior nasal spine (ANS) point between 5 and 10 years of age, although there was little change from average in the anteroposterior length of the mandibular body and the height of the mandibular ramus. So, while maxillary growth was reduced, mandibular growth did not significantly change. Cast analysis showed that the increase in arch length was greater than in arch width for both the maxilla and mandible. There was little increase in alveolar ridge height in the anterior region but a considerable increase in the height of the alveolar ridge in the middle and the posterior region. Our findings concluded that the absence of teeth did not affect the growth of the jaws, and it is probable that the denture flange did not arrest the jaw growth, but rather improved the masticatory function by providing good denture stability and retention.     

Effect of implant support on distal extension removable partial dentures: in vitro assessment

The implants in implant-supported removable partial dentures (RPDs) are placed in the edentulous ridge to stabilize the RPD and minimize the resultant rotational movement. This study investigated the effect of implant placement on RPD stability. A model simulating a mandibular bilateral distal extension missing was fabricated using epoxy resin and silicone impression material as thin (1 mm) and thick (2 mm) soft tissues. Five pressure sensors (PS-10K, Kyowa, Tokyo, Japan) were attached near the left and right first molars (#36 and #46), first premolars (#34 and #44) and medio-lingual alveolar crest. Five bilateral distal extension RPDs with Co-Cr frameworks were conventionally fabricated. After the implants were placed at the bilateral second molar areas, healing caps (4.5 mm high) were connected to the denture base with autopolymerized resin to support the RPD. As in a conventional RPD, sealing screws were placed without connecting them. Loads up to 5 kg were applied, and the pressure and displacement of the RPDs (n = 5) were simultaneously measured and analysed using the Wilcoxen test (alpha = 0.05). There was less pressure on both thin and thick soft tissues, the #36, #46 and the medio-lingual alveolar crest from the implant-supported RPD than from the conventional RPD (P < 0.05). There were no significant differences in pressure on #34 and #44 between the two RPDs (P > 0.05). There was significantly less denture displacement of the implant-supported RPD than of the conventional denture (P < 0.05). Implant support helped prevent the displacement of distal extension RPDs and decreased the pressure on soft tissues.     

两种剂型义齿粘附剂对全口义齿咀嚼功能影响的初步研究

目的：评价两种剂型义齿粘附剂对牙槽嵴较为低平的无牙颌患者的作用效果,并对两种粘附剂进行相互比较.方法：测定10名牙槽嵴较为低平的无牙颌患者使用两种粘附剂前后咀嚼效能,同时以问卷形式调查患者的主观评价.结果：使用两种剂型粘附剂后,患者的咀嚼效能都得到显著改善,主观评价也较为理想.结论：义齿粘附剂可显著改善牙槽嵴较为低平的无牙颌患者的咀嚼功能.     

Occlusal contacts of edentulous patients with mandibular hybrid dentures opposing maxillary complete dentures.

The purpose of this study was to evaluate differences between the occlusal contacts of edentulous patients with mandibular implant-supported hybrid dentures opposing maxillary complete dentures and those of patients with conventional maxillary and mandibular complete dentures. Six parameters related to occlusion were measured in the 2 groups (n = 40 for each group) using pressure-sensitive film. The mean values generated by each test group for each parameter were compared using a t test. Pearson's correlation coefficients between occlusal force, age, and time in function were examined. Occlusal force and area in the implant denture wearers were larger than those in the conventional denture wearers. No significant difference was seen in occlusal force balance between the left and right sides. The center of occlusal load in the implant denture wearers was more anterior. The maxillary denture may become more unstable in implant denture wearers. It is suggested that the stability and retention of a maxillary denture be checked and the occlusion be adjusted more frequently in the hybrid denture wearer than in the conventional denture wearer.     

Does the Presence of Anterior Mandibular Teeth Increase the Incidence of Denture Stomatitis?

Purpose : To compare the frequency of denture stomatitis (DS) under maxillary complete dentures (CDs) in patients with opposing mandibular distal extension removable partial dentures (RPDs) and CDs. Materials and Methods : Participants included 365 maxillary CD wearers (241 women, mean age 70.5 ± 13.2 years; 124 men, mean age 71.5 ± 10.4 years) from 7 rest homes in Istanbul. A total of 268 had mandibular CDs; 97 had mandibular distal extension RPDs. Two independent, calibrated examiners performed oral examinations. Presence of maxillary denture‐related stomatitis and the effect of risk factors on DS were evaluated and recorded. Results : The frequency of palatal DS (Newton I‐III) was 45.1% (n = 121) in the mandibular CD group and 49.5% (n = 48) in the mandibular distal extension RPD group, a statistically insignificant difference (p= 0.4). Factors significantly associated with palatal DS were maxillary denture age (p= 0.02), reduced occlusal vertical dimension (p= 0.04), and nocturnal denture wear (p= 0.03). Conclusion : In this study, DS beneath maxillary CDs did not differ between mandibular distal extension RPD and CD wearers. The presence of mandibular anterior teeth did not influence the occurrence of palatal DS.     

Shortcomings of prosthodontic rehabilitation of patients living in long‐term care facilities

Removable dentures are a non‐invasive, cost‐effective prosthodontic solution for the reduced dentition. Their intended purpose is the rehabilitation of harmonious oral function and aesthetics on a long‐term basis. The prevalence of removable dentures among patients of advanced age is high and the quality of the dentures is often poor. The aim of this study was to find the most important shortcomings of removable dentures and address the main targets for improving the quality of prosthodontic rehabilitation. The records from dental check‐ups in Austrian residential homes were analysed retrospectively. Dental anamnesis questionnaires and data from the clinical examinations of 105 denture wearers were analysed. The functional condition and retention of 192 dentures had been assessed, as well as the impact of the dentures on the intra‐oral tissues. Insufficient denture retention was very common, particularly in the lower jaw (56·0%). Problems with the masticatory function were reported by 26.7% of the denture wearers, 11·4% were dissatisfied with the denture aesthetics, and 4·8% had difficulties with phonetics. Traumatic ulcers were found in 18·1%. Cracks, broken pieces (6·3%) or missing denture teeth (2·1%) were rare. It may be assumed that the findings of the present study also apply to a great percentage of community‐dwelling seniors. The most important issues in prosthodontic rehabilitation with removable dentures are denture retention and masticatory function. Regular dental check‐ups, denture adjustment and, when necessary, relining can maintain the primary denture quality and prevent damages of the oral tissues caused by ill‐fitting dentures.     

全口义齿基托边缘位置及形态的临床研究

目的：分析义齿基托边缘实际位置和形态以及与上下颌解剖标志的关系。方法：按照规范化标准制取功能性印模,为10名无牙颌患者进行全口义齿修复。在义齿试戴前后及义齿使用合适后,测量基托边缘厚度,记录基托边缘调改量,观察基托边缘和上下颌解剖标志的关系。结果：全口义齿基托边缘在翼上颌切迹区、颊棚区、远中颊角区、舌骨嵴区的调改量大,具有统计学意义（P ＜0．05）。下颌义齿颊侧基托边缘在颊棚区与外斜嵴平齐,在远中颊角区避让咬肌附丽。舌侧基托边缘在下颌隆突区与下颌隆突平齐。结论：全口义齿基托边缘在翼上颌切迹区、颊棚区、远中颊角区、及舌骨嵴区易过度伸展。