Long-term assessment of the periodontal health of removable partial denture wearers: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The long-term effects of wearing removable partial dentures (RPDs) remain unclear.

PURPOSE

This systematic review addressed the question "Is the long-term use of RPDs deleterious to the remaining teeth?"

MATERIAL AND METHODS

This review was guided by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. Six databases and nonpeer-reviewed literature were searched in April 2024 without language or follow-up restrictions. Only clinical studies evaluating RPD long-term use were included. The risk of bias and evidence certainty were assessed (RoB 2.0; ROBINS-I; GRADE), and meta-analyses were conducted for survival rate and periodontal health (α=.05).

RESULTS

A total of 5577 records were identified, and 46 studies covering data from 4359 prostheses and 4072 participants (mean age 60 ±5.2 years) were included. A low to moderate risk of bias was found. A 5-year survival rate of 95.1% (ER=0.951; 95% CI=0.900 to 0.977; P<.001) and 91.7% (ER=0.917; 95% CI=0.870 to 0.948; P<.001) was found for cast-clasp RPD and RPDs retained by telescopic crowns respectively, with no difference between them (P=.71). Abutments (OR=1.99, 95% CI=1.32 to 3.01; P=.001) and nonvital teeth (HR=2.961; 95% CI=2.023 to 4.335; P<.001) presented a higher risk of extraction after 5 years. Tooth mobility (P=.98) and probing depth (P=.50) remained unchanged, while the gingival index increased (MD=0.477 (95% CI=0.12 to 0.83; P=.008).

CONCLUSIONS

A high survival rate was found for both cast-clasp RPD and RPDs retained by telescopic crowns, with few periodontal changes to the remaining teeth.

A New Proposal for Calibrated Gauges for Removable Partial Dentures: A Finite Element Analysis

AIM

The aim of this study was to evaluate the stress distribution of a planned removable partial denture (RPD) using new proposals for calibrated gauges of 0.3 mm and 0.35 mm undercuts through the three-dimensional (3D) finite element methodology, and compare them with 0.25 mm and 0.5 mm gauges that are already existing in clinical practice.

MATERIALS AND METHODS

Kennedy class-I edentulous 3D models and their respective RPDs (InVesalius software; Rhinoceros and SolidWorks CAD) were created and exported to the finite element program HyperMesh 2019 for mesh configuration. In the following steps, axial loading (0º) of 40 N per point was performed, with 3 points on the molars and 2 points on the premolars, totaling 280 N unilaterally. The model was processed by the OptiStruct 2019 software and imported into the HyperView 2019 software to obtain the stress maps (MPa).

RESULTS

The use of 0.30 and 0.35 mm calibrated gauges presented tensions similar to those with the 0.25 mm gauge (gold standard) and caused no significant damage to biological structures. The use of a 0.5 mm undercut caused greater traction force in the periodontal ligament of the abutments.

CONCLUSIONS

The 0.35 mm undercut seems promising as it presented more favorable results in this simulation, on the other hand, a 0.5 mm undercut is greater than that necessary for retainers made of CoCr.

CLINICAL SIGNIFICANCE

This study aims to measure a new undercut gauge (0.35 mm) to increase the retention area in abutment teeth of removable partial dentures.

Finite Element Study of Stress Distribution with Tooth-Supported Mandibular Overdenture Retained by Ball Attachments or Resilient Telescopic Crowns

Objective The removable partial denture must keep health of the remaining teeth and the supporting tissues through the distribution of chewing forces on the abutment teeth and alveolar process.

This study aimed to evaluate stress distribution with canines-supported mandibular overdenture retained by two different attachment types: ball attachments or resilient telescopic crowns.

Materials and Methods Two 3-dimensional finite element models consisting of the cortical mandible bone, cancellous mandible bone, oral mucosa, canines, periodontal ligaments, the two attachment types, and overdenture were simulated. The models were imported into the mathematical analysis software Ansys Workbench V 15.0. All materials were considered to be homogeneous, isotropic, and linearly elastic. A vertical bilateral load of 120 N was applied to the central fossa of the first molars. The von Mises stress was calculated for canines, cortical, and cancellous bone.

Results The maximum von Mises stress of the ball attachments model was 35.61, 4.28, 7.82, and 1.29 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively. The maximum von Mises stress of the resilient telescopic crowns model was 39.22, 4.74, 7.06, and 1.05 MPa for canines, cortical alveolar bone of canines, cortical alveolar bone at the distal end of the overdenture, and cancellous alveolar bone of canines, respectively.

Conclusion Resilient telescopic crowns distribute the stresses between canines, alveolar bone of canines, and overdenture supporting alveolar bone. Ball attachments transfer less stress to the canines and cortical alveolar bone of the canines, but more stress to the cancellous alveolar bone of canines and alveolar bone at distal end of the overdenture. Resilient telescopic crowns are preferred over ball attachment when the abutment teeth have good periodontal support.

The Use of Acrylate Polymers in Dentistry

The manuscript aimed to review the types of acrylate polymers used in dentistry, as well as their chemical, physical, mechanical, and biological properties. Regarding their consistency and purpose, dental acrylate polymers are divided into hard (brittle), which includes acrylates for the production of plate denture bases, obturator prostheses, epitheses and maxillofacial prostheses, their repairs and lining, and soft (flexible), which are used for lining denture bases in special indications. Concerning the composition and method of polymerization initiation, polymers for the production of denture bases are divided into four types: heat-, cold-, light-, and microwave-polymerized. CAD/CAM acrylate dentures are made from factory blocks of dental acrylates and show optimal mechanical and physical properties, undoubtedly better monomer polymerization and thus biocompatibility, and stability of the shape and colour of the base and dentures. Regardless of the number of advantages that these polymers have to offer, they also exhibit certain disadvantages. Technological development enables the enhancement of all acrylate properties to respond better to the demands of the profession. Special attention should be paid to improving the biological characteristics of acrylate polymers, due to reported adverse reactions of patients and dental staff to potentially toxic substances released during their preparation and use.

FINITE ELEMENT EVALUATION OF THE EFFECT OF ADHESIVE CREAMS ON THE STRESS STATE OF DENTURES AND ABUTMENT TEETH

The appropriate fit of removable partial dentures (RPDs) is hypothesized to lead to lower tooth mobility. An adhesive layer between the denture and oral mucosa can facilitate better denture retention and therefore increased stability. Study objectives were to model and compare the response of abutment structures with and without the application of a denture adhesive and to observe the stress response of abutment periodontal ligaments (PDLs) during the application of occlusal force on the RPD. A 3D finite element (FE) model was developed from computer tomography datasets of the mandibular region and the RPD. An adhesive layer was developed by extending the denture surface and using the Prony series approximation of rheological data to implement a viscoelastic material model. FE simulations were performed by applying a bite force on one of the denture segments, with the resulting deformation in PDL compared between the model with the adhesive layer and the base model without. The maximum deformation of 15[Formula: see text][Formula: see text]m was observed in the 2nd molar abutment PDL with the implementation of the adhesive, as compared to 42[Formula: see text][Formula: see text]m for the model without. The lower impact of RPDs on the supporting abutment teeth could potentially reduce the discomfort of denture wearers.

Three interfaces of the dental implant system and their clinical effects on hard and soft tissues

Anatomically, the human tooth has structures both embedded within and forming part of the exterior surface of the human body. When a tooth is lost, it is often replaced by a dental implant, to facilitate the chewing of food and for esthetic purposes. For successful substitution of the lost tooth, hard tissue should be integrated into the implant surface. The microtopography and chemistry of the implant surface have been explored with the aim of enhancing osseointegration. Additionally, clinical implant success is dependent on ensuring that a barrier, comprising strong gingival attachment to an abutment, does not allow the infiltration of oral bacteria into the bone-integrated surface. Epithelial and connective tissue cells respond to the abutment surface, depending on its surface characteristics and the materials from which it is made. In particular, the biomechanics of the implant-abutment connection structure (i.e., the biomechanics of the interface between implant and abutment surfaces, and the screw mechanics of the implant-abutment assembly) are critical for both the soft tissue seal and hard tissue integration. Herein, we discuss the clinical importance of these three interfaces: bone-implant, gingiva-abutment, and implant-abutment.

Predictors of tooth loss in Brazilian older adults: An 8-year follow-up

OBJECTIVE

To investigate the risk factors for tooth loss after 8 years among community-dwelling older adults in a southern Brazilian city.

METHODS

In 2004, 388 dentate community-dwelling older adults from Carlos Barbosa, southern Brazil, were selected using simple random sampling. In 2012, the follow-up consisted of 199 (51.3%) participants. Data collection comprised an interview with data about socio-demographic, behavioural and access to services and an oral examination. The outcome variable of this study is the ratio between the sum of the teeth lost during the 8-year period of follow-up, and the sum of the teeth present in 2004, per person, modelled through binomial regression analysis.

RESULTS

Being older (IOR = 1.03, 95% CI: 1.00-1.06), living in a rural area (IOR = 1.56, 95% CI: 1.17-2.07), earning two or more monthly minimum wages (IOR = 1.46, 95% CI: 1.09-1.96), living alone (single, widowed or divorced; IOR = 1.36, 95% CI: 1.00-1.85), having more gingival bleeding sites (IOR = 1.01, 95% CI: 1.00-1.02) and wearing partial removable prosthesis (IOR = 2.82, 95% CI: 2.15-3.71) were risk factors for tooth loss. Approximately 48% of the participants lost one or more teeth over the 8-year follow-up period.

CONCLUSION

Socio-demographic, economic and clinical variables were associated with the risk for tooth loss. This might be a result of social determinants of health influencing people's access to oral health care, oral health behaviours and oral health status. Public policy aimed at older adults living in rural areas, living alone and using removable dentures may contribute to reducing the risk of tooth loss.

Effect of Acrylic Removable Partial Denture in Caries Prevalence Among Diabetic and Non-Diabetic Patients

Background:

Dental caries is the most prevalent dental disease affecting human race. The etiology and pathogenesis of dental caries are known to be multifactorial. Studies have shown that removable partial dentures in the oral cavity increases the biofilm formation and consequently an increase in the occurrence of caries and periodontal diseases. There is a complex relationship between diabetes mellitus and dental caries. Patients with diabetes are more susceptible to oral sensory, periodontal, and salivary disorders which could increase the risk of developing new and recurrent dental caries. Therefore, the aim of the study was to assess the prevalence of dental caries among diabetic and non-diabetic acrylic removable partial denture wearers.

Materials and Methods:

Individuals participating in the study were partially edentulous and aged between 18 and 64 years. Patients were screened at Out patient department (OPD) in the Department of Prosthodontics JSSDCH, among which 60 patients were diabetic based on the random blood sugar level more than 160 mg/dl—30 patients were wearing RPD and 30 were without RPD. And 60 non-diabetic patients were selected among which 30 were wearing RPD and 30 without RPD. A total 120 patients were screened. Dental caries prevalence was assessed using Decayed, Missing, Filled (DMFT) index.

Results:

Diabetic group unrehabilitated with removable partial prosthesis showed significant difference in the number of missing teeth when compared to non-diabetic patients without removable prosthesis (P < 0.05).

Conclusion:

Removable partial denture prosthesis had less impact on prevalence of dental caries with good oral hygiene, following post insertion RPD instructions and regular dental visits irrespective of diabetes.

Mechanical Evaluation of Implant-Assisted Removable Partial Dentures in Kennedy Class I Patients: Finite Element Design Considerations

The main purpose of this work was to construct a clinically valid numerical model of a mandibular Kennedy class I patient rehabilitated with a conventional removable partial denture and another two with implant-assisted removable partial dentures at two different implant locations. The selected patient was classified as ASA I and its mandible geometry reconstruction was performed by the conversion of the Cone-Beam computed Tomography (CBCT) scan raw medical data into a 3D model and subsequent conversion to a CAD file by reverse engineering methods. The soft tissue and removable denture geometries were also included in the CAD model as well as implants, ball attachments and matrix. Moreover, periodontal ligament was modelled by offsetting the mesh of the root surface of each tooth. The finite element results showed that the installation of a dental implant in each of the bilateral edentulous regions helps providing support and retention to the extension bases of the Removable Partial Denture (RPD) and significantly reduces the vertical and anterior-posterior displacements, regardless of its position.

Evaluation of the effect of ultraviolet light polymerized clear adhesive on shear and tensile bond strength of heat cure denture base resin to the cobalt-chromium retentive minor connector: An in vitro study

Aim:

The aim of this study is to evaluate the efficacy of new material ultraviolet (UV) light polymerized clear adhesive on shear and tensile bond strength of heat cure denture base resin (Polymethylmethacrylate (PMMA)) to cobalt-chromium (Co-Cr) retentive minor connector.

Setting and Design:

Comparative evaluation- In-vitro study.

Materials and Methods:

Sixty samples of Co-Cr plates mimicking minor connectors were fabricated. Thirty samples were coated with new material UV light polymerized clear adhesive and cured under UV light source for 10 min. In gun-metal flask, metal plates were placed in the lower compartment over it. Heat cure acrylic resin was packed in the dough stage with the help of clamps and processed according to the manufacturer's instructions. Samples were kept in artificial saliva for 90 days. Shear and tensile bond strengths were calculated of each sample with a Universal testing machine, and results were statistically analyzed. Type of bond failure was observed for each sample under stereomicroscope.

Statistical Analysis Used:

Unpaired t test.

Results:

Tensile bond strength, as well as shear bond strength, showed that 0.93 N and 1.64 N respectively for without application of new adhesive was more as compared to that of samples with the application of new adhesive which is 0.75 N and 1.54 N respectively. Bond failure was found to be an adhesive failure in resin–metal interface.

Conclusions:

Excellent bonding seen between the new adhesive and acrylic interface but limited effect on the metal interface. To increase bond strength between metal and resin interface, some surface treatment with the metal surface is needed to increase the bonding of the new adhesive to the metal surface.

Communication Between Dentists and Dental Technicians During the Fabrication of Removable Partial Dentures in Khartoum State, Sudan

OBJECTIVES

To investigate the quality of communication between dentists and dental laboratory technicians in private dental laboratories in Khartoum State related to fabrication of removable partial dentures.

METHODS

This was a descriptive cross-sectional study, in which dental technicians were interviewed regarding the quality of instructions they received from dentists concerning the construction of removable partial dentures (RPD). Eighty cases were investigated, 69 acrylic (A-RPD) and 11 cobalt chromium (CC-RPD) dentures.

RESULTS

Although dentists provided no instructions in 21.7% of A-RPD cases, they gave instructions in all CC-RPD cases. Instructions were primarily given verbally (55.1% in A-RPD, 54.5% in CC-RPD cases), as opposed to written (23.3% in A-RPD, 45.5% in CC-RPD cases). Most design components for A-RPD and CC-RPD cases were not clearly prescribed, and instructions were clear in only 8.7% of A-RPD and 36.4% of CC-RPD cases. Notably, surveying of casts by dentists was only done in 18.2% of CC-RPD cases. Most technicians (84.2%) believed that prosthesis design was the dentists' responsibility. Technicians needed to contact dentists for clarification of design significantly more frequently for CC-RPD (p=0.004) cases.

CONCLUSION

Quality of communication between dentists and private laboratory technicians in Khartoum State with regard to removable partial denture construction was largely inadequate.