The Effect of Removable Partial Dentures on Alveolar Bone Resorption: A Retrospective Study with Cone‐Beam Computed Tomography

Purpose: The aim of this study was to compare vertical and horizontal mandibular alveolar bone resorption by measuring bone morphological variation in Kennedy Class II removable partial denture (RPD) wearers and non‐wearers using cone‐beam computed tomography (CBCT). Materials and Methods: In total, 124 sites in the CBCT scans of 62 (29 RPD non‐wearers, 33 RPD wearers) Kennedy Class II patients were analyzed retrospectively. Three‐dimensional representations of the mandible with superimposed cross‐sectional slices were developed with the CBCT scans to evaluate the mandibular alveolar height and width by measuring distances between the mandibular canal, mylohyoid ridge, alveolar crest, and lower border of the mandible in four regions (eight sites) of Kennedy Class II non‐wearers and wearers of RPDs. Results: Mandibular alveolar bone height and width were significantly lower in edentulous sites when compared with dentate sites in both Kennedy Class II non‐wearers and wearers of RPDs (p < 0.05). Additionally, mean vertical and horizontal mandibular bone resorption was significantly higher in RPD wearers than in non‐wearers (p < 0.05). Conclusions: Vertical and horizontal alveolar bone resorption was found to be higher in the RPD wearing patients when comparing the dentate and edentulous sites.     

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.     

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.     

Cantilever bridges or removable partial dentures in geriatric patients: a two-year study

The purpose of this study was to compare prosthetic, functional and occlusal conditions in twenty-seven patients treated with distally extending cantilever bridges and twenty-six patients treated with removable partial dentures (RPD) in the mandible. All patients had a complete upper denture. Mean age of the patients in both groups was about 69 years. The patients were under a supervised oral hygiene care throughout the 2-year study period. There were 6.9 +/- 1.7 mandibular teeth left in the bridge group and 7.5 +/- 1.7 in the RPD group and the mean number of posterior teeth (natural teeth/denture teeth/pontics) in occlusion was 4.1 +/- 1.1 and 7.3 +/- 1.4, respectively. During the study period signs and symptoms of mandibular dysfunction became significantly aggravated in the RPD group, P less than 0.05. A balanced occlusion in the muscular contact position was observed in 90% of the patients in the bridge group and in 76% of the RPD wearers. During the study period the need for dental or prosthetic treatment was negligible in the patients treated with bridges. In the RPD group, twenty-two teeth were restored with fillings due to caries and in eight patients major adjustments of the sublingual bar were necessary due to irritation of the oral mucosa. This study has shown that treatment with distally extending cantilever bridges in the mandible is a favourable alternative to treatment with removable partial dentures in elderly patients with a reduced dentition.     

Mandibular bone resorption in patients treated with tissue-integrated prostheses and in complete-denture wearers

Mandibular bone resorption was studied in patients treated with tissue-integrated prostheses (TIP) and in complete-denture wearers by distance and area measurements on cephalometric radiographs. The area measurements were performed by means of a computer. Two TIP groups with short and long periods (mean = 2.4 and 23.9 years) of edentulousness and wearing complete dentures before fixture installation were followed up over 7-8 years. Mandibular bone resorption was remarkably small behind the distally positioned fixtures in comparison with the corresponding region in complete-denture wearers. Patients with complete dentures showed a continuous resorption of the mandibular alveolar ridge over 21 years, even though there were great individual variations. The bone loss was most pronounced anteriorly and during the first 2 years after extraction of the residual teeth. It is concluded that treatment with tissue-integrated prostheses seems to reduce bone resorption in the mandible, probably owing to favorable load conditions and adequate stimulation of the bone.     

Mastication in subjects with extremely shortened dental arches rehabilitated with removable partial dentures

Mastication was evaluated in subjects presenting extremely shortened dental arches (ESDAs) rehabilitated with mandibular free-end removable partial dentures (RPDs). Subjects were divided into four groups (n = 10): those with a complete dentition, those with ESDAs, and those with ESDAs who were rehabilitated with an RPD, who were evaluated both with and without their prostheses. Mastication was measured through masticatory performance, time, and ability. RPD wearers showed higher masticatory performance (P < .01) and ability (P < .001) and lower masticatory time (P < .001) than when not wearing their prostheses as well as ESDA subjects who had not received RPD therapy. Those with a complete dentition showed the best results (P < .001). It can be suggested that RPDs improve mastication in ESDA subjects but without achieving normal mastication levels.     

Oral health status of patients 5-6 years after placement of cobalt-chromium removable partial dentures

This study is a clinical survey of cobalt-chromium (Co-Cr) removable partial denture (RPD) wearers that aimed to investigate the effects of denture wearing on oral tissues. A random sample of patients who had received their dentures 5-6 years previously from a dental teaching hospital in Hong Kong was selected. Those who had been constantly wearing the RPDs were examined by one calibrated examiner under an optimal clinical setting. The patients' dental, periodontal and mucosal status were assessed. A total of 87 patients were examined. Mucosal lesions under the Co-Cr RPDs were uncommon in this study sample. However, there was a high prevalence of plaque, gingivitis and gingival recession, especially in dento-gingival surfaces in close proximity (within 3 mm) to the dentures. Thus, there is a special need for regular oral hygiene reinforcement, scaling and prophylaxis among RPD wearers. Despite a low caries incidence in the study sample, root caries were found to be associated with contact with the RPDs (P < 0.05) but coronal caries were not. It is recommended that coverage of the exposed root surfaces by RPD components should be avoided. Also, topical fluorides should be regularly applied onto exposed root surfaces as a preventive measure.     

Masticatory performance with mandibular implant-retained overdentures

It was investigated in a clinical trial whether the masticatory performance of complete-denture wearers depended on the support for their mandibular dentures by implants or mucosa. The trial involved the provision of a new maxillary denture and either a new conventional mandibular denture (mucosa-borne), a mandibular overdenture retained by two IMZ-implants (implant-mucosa-borne), or a mandibular overdenture on a transmandibular implant (TMI; mainly implant-borne). In comparison with mandibular implant-retained overdentures, subjects with conventional dentures needed 1.5 to 3.6 times more chewing strokes for an equivalent reduction in particle size. No differences in masticatory performance were found between subjects with IMZ-implants and those with TMI. This suggests that the increased stability of the mandibular denture with implants determines the wearer's masticatory performance, rather than the support by implants.     

Functional mobility measurement of removable partial dentures using newly-developed analyzing system in six degrees of freedom--effect of cusp inclination of molar artificial teeth on denture displacement in function]

A measuring system to record three-dimensional displacement of removable partial dentures (RPDs) in six degrees of freedom has been developed. The system employed three pairs of photodiode and LED that were set up in a triangle. This system was capable of recording the in vivo RPD displacement with a recording sensitivity of 0.1 mm. In vivo displacement of upper RPDs with unilateral distal extension saddle was investigated using this measuring system to determine the effect of artificial cusp inclination of molar teeth on denture mobility. Two groups of different artificial dentition were switched to be attached to each of three experimental RPDs. The artificial teeth with cusp inclinations were calibrated to contact with opposing natural dentition during lateral grinding of the mandible, while the other artificial teeth were prepared to disclude with the mandibular teeth (flat-cusp group). Displacement range and average position of a reference point at the first molar of the RPDs during mastication were measured and analyzed as a function of the cusp inclination and the test food. As a result, the average displacement of the RPDs toward the edentulous ridge was smaller in the cusp group than that in the flat-cusp group, while the range of horizontal displacement in the buccal-palatal direction was greater in the former group than the latter. The denture wearers demonstrated typical grinding strokes at the end of the closing phase of the mandiblar movements when they chewed a peanut, which was attributed to a wide range of horizontal displacement of the dentures.     

Treatment outcomes with removable partial dentures: a comparison between patient and prosthodontist assessments

PURPOSE: This article presents the results from a survey of patients' degree of satisfaction with their removable partial dentures (RPD) and the comparison between patient and prosthodontist assessments. MATERIALS AND METHODS: A total of 165 experienced RPD wearers filled in a questionnaire and graded their RPDs depending on their level of satisfaction. A scale ranging from 1 to 5 was used to assess general satisfaction with RPDs and to assess their esthetics, retention, and hygiene. A specialist in prosthodontics assessed the same prostheses using the same scale, not knowing the patient's opinion. RESULTS: The patients' assessments were high, and more than half of them graded their dentures as excellent. On average, all variables were assessed higher by the patients than by the prosthodontist (P < .001). For the patients who gave the worst grades to their dentures, the grades were lower than the prosthodontist's (P < .001), while the satisfied patients graded their dentures much better than did the prosthodontist (P < .001). CONCLUSION: On average, patient assessment of the treatment outcomes with RPDs was less critical than prosthodontist assessment. However, the few dissatisfied patients assessed their dentures worse than did the prosthodontist.     

Incidence of various classes of removable partial dentures.

The purpose of a classification for removable partial dentures (RPDs) is to simplify identification and enhance its teaching. A classification also allows a longitudinal comparison of various classes of RPDs to determine whether the teaching of RPD design is consistent with the relative frequencies of RPD use. This study surveyed the types of removable partial dentures being fabricated in a regional dental laboratory and compared these findings with data from previous studies. Results indicate that mandibular RPDs are more common than maxillary RPDs and the class I mandibular RPD is the most common type of RPD for either dental arch. A palatal strap was the most frequently used maxillary major connector and a lingual bar was used three times more often than a lingual plate in the mandibular arch. Cast circumferential clasps were used twice as often as RPI clasp designs. The percentage of Kennedy class I RPDs was 40%, class II 33%, class III 18%, and class IV 9%. Comparisons with a previous study indicate the percentage of Kennedy class II has increased, whereas class I, class III and class IV RPDs have not changed significantly. Findings of the study indicate that the frequency of use of the various types of RPDs have changed in the past 30 years.     

Periodontal conditions following treatment with distally extending cantilever bridges or removable partial dentures in elderly patients. A 5-year study

The aim of the present study was to evaluate the periodontal conditions following treatment with distally extending cantilever bridges or removable partial dentures (RPDs) in elderly patients. All participants had a complete denture in the maxilla and moderate-to-advanced bone loss around the teeth present in the mandible. After undergoing periodontal treatment, 27 patients were treated with distally extending cantilever bridges and 25 patients with a RPD. During the first 2 years following prosthetic treatment, the patients were recalled twice a year and during the last 3 years once a year for oral prophylaxis and assessment of the periodontal status. The patients treated with a RPD showed higher mean Plaque and Gingival Indexes than the patients treated with cantilever bridges. No change in probing pocket depths was observed in either group, and only a small decrease in radiographic alveolar bone height was revealed. In conclusion, only minor changes in the periodontal conditions were recorded during the 5 years of observation after treatment with cantilever bridges or RPDs.     

Veterans administration cooperative dental impant study—Comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part II: Comparison of success rates and periodontal health between two treatment modalities

Five Veterans Administration centers have participated in a study to determine whether fixed partial dentures (FPDs) supported by blade implants offer an acceptable substitute for mandibular unilateral or bilateral distal-base extension removable partial dentures (RPDs). The study design and methodology have been described in Part I. A total of 232 patients received comprehensive dental care including RPDs for 118 patients and FPDs for 114. Prespecified criteria determined treatment failures. During the 60-month period, treatment failures occurred in 19 FPD patients and 30 RPD patients. Ten FPD failures occurred before and nine after the FPD insertion. Five RPD failures were caused by abutment tooth loss and 25 for not using the RPD while eating. Life table analysis showed 5-year success rates of 84.2% for the FPD and 74% for the RPD. The 17.9% higher FPD success rate in Kennedy class II patients was both statistically and clinically significant. Excluding the 10 early failures, the 5-year FPD success rate war 91.5%. Of the 170 attempted implants, 26 failed, including 12 before the FPD fabrication. Radiographic assessments by a panel of three judges showed no bone deterioration during baseline to 60 months in 29.6%, slight in 25.4%, moderate in 15.9>, marked in 27%, and severe deterioration in 2.1% of the implant posts.     

Systematic Clinical Evaluation and Correction Procedures for Support of Removable Partial Dentures

Support, retention, and bracing are the three main functions of a direct retainer in removable partial dentures (RPDs). RPDs must have sufficient supporting ability for proper occlusal rehabilitation. Support ability depends on the fit, size, shape, and location of the occlusal rest. Support cannot be adjusted chairside in most cases. The purpose of this article is to present systematic evaluation criteria for support in an RPD and to describe methods for adjusting cast clasps with improper support. Appropriate design of RPDs and preparation of abutments are also described.     

Veterans Administration Cooperative Dental Implant Study--comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part II: Comparisons of success rates and periodontal health between two treatment modalities

Five Veterans Administration centers have participated in a study to determine whether fixed partial dentures (FPDs) supported by blade implants offer an acceptable substitute for mandibular unilateral or bilateral distal-base extension removable partial dentures (RPDs). The study design and methodology have been described in Part I. A total of 232 patients received comprehensive dental care including RPDs for 118 patients and FPDs for 114. Prespecified criteria determined treatment failures. During the 60-month period, treatment failures occurred in 19 FPD patients and 30 RPD patients. Ten FPD failures occurred before and nine after the FPD insertion. Five RPD failures were caused by abutment tooth loss and 25 for not using the RPD while eating. Life table analysis showed 5-year success rates of 84.2% for the FPD and 74% for the RPD. The 17.9% higher FPD success rate in Kennedy class II patients was both statistically and clinically significant. Excluding the 10 early failures, the 5-year FPD success rate was 91.5%. Of the 170 attempted implants, 26 failed, including 12 before the FPD fabrication. Radiographic assessments by a panel of three judges showed no bone deterioration during baseline to 60 months in 29.6%, slight in 25.4%, moderate in 15.9%, marked in 27%, and severe deterioration in 2.1% of the implant posts.     

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.     

线性(牙合)总义齿固位稳定性的研究

目的：通过对线性He总义齿固位的定量检测及患者的主观评判，验证线性He总义齿的He型设计在静态及动态下对义齿固位与稳定性的影响。方法：利用Hz-1型固位力测试仪对25例线性He总义齿修复患者进行上、下颌总义齿静态固位力的测试，同时针对功能状态下的主观固位感觉进行问卷调查。结果：线性He上凳总义齿在两种状态下均具有良好的固位；剩余牙槽嵴骨吸收严重的线性He下颌总义齿修复患者的静态固位力值低，但主观感觉固位良好；患者戴用线性He总义齿的主观固位感觉明显优于原解剖式He总义齿。结论：对于剩余牙槽骨吸收严重的患者，线性He总义齿在功能状态下可获得良好的义齿固位和稳定性，有利于义齿功能的发挥。     

Titanium for removable partial dentures (III): 2-year clinical follow-up in an undergraduate programme

This study examined the success of titanium (Ti) removable partial dentures (RPDs) compared with that of cobalt-chromium (Co-Cr) RPDs using a randomized controlled clinical trial. Thirty-eight RPD patients were provided with either Co-Cr (20 patients) or Ti (18 patients) RPDs. The total numbers of dentures was 31 (13 maxillary, 18 mandibular) for Co-Cr and 23 (11 maxillary, 12 mandibular) for Ti. Patients were reviewed for 24 months following denture issue. After the initial 12 months, 20 clinical problems were recorded and became the criteria for subsequent assessment. Incidence of failure was analysed using both Fisher's exact test and the chi square test at a significance level of P<0.05. Fracture of retainers in both metals occurred only in the first 12 months. Some failure types presented at significantly higher levels in the first 12 months but there were no significant differences between the two in all the criteria examined between the 12- and the 24-month reviews. Although differences existed in failure types between Co-Cr and Ti RPDs during the early review stages, the overall success rate of Ti RPDs was comparable with that of Co-Cr RPDs after 24 months. The higher incidence of failures in Ti RPDs prior to the 12-month review suggests the importance of taking its lower rigidity into account when designing RPDs.     

Symptoms of mandibular dysfunction in complete denture wearers

Recent epidemiological studies have shown that symptoms of mandibular dysfunction are very common, but prosthodontists have thought that complete denture wearers are spared such complications. However, in recent reported series of patients who have sought advice for mandibular dysfunction complete denture wearers have been included. According to epidemiological data individuals with few remaining natural teeth had more symptoms of dysfunction than those with most of their natural teeth, and complete denture wearers had more symptoms of mandibular dysfunction than subjects with natural teeth. Mandibular and temporomandibular joint dysfunction symptoms have a heterogeneous background, but occlusal instability is an important aetiological factor. In complete denture wearers with mandibular dysfunction, symptoms often disappear after improvement of the occlusion.