Good occlusal practice in removable prosthodontics

Does occlusal morphology of artificial teeth improve chewing of removable dentures wearers? A systematic review and meta-analysis

PURPOSE

This systematic review aimed to verify whether anatomic, semi-anatomic, or nonanatomic occlusal morphology of artificial teeth improves the masticatory function of complete or removable partial denture wearers.

MATERIALS AND METHODS

According to the PICO strategy, six databases and the grey literature were searched to identify randomized (RCT) and non-randomized clinical trials (N-RCT) comparing masticatory function, in terms of masticatory performance and efficiency, and muscle activity as primary outcomes; and patient-reported results (O) in individuals using removable dentures (P) with different occlusal morphologies of artificial teeth (I/C). Masticatory ability, satisfaction with the prosthetic treatment, and oral health-related quality of life (OHRQoL) were evaluated as secondary outcomes. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomized trials (RoB 2.0) for RCT and Risk of Bias for non-randomized studies with intervention (ROBINS-I) for N-RCT studies. Meta-analyses were performed to compare primary outcomes and masticatory ability between the occlusal morphologies of artificial teeth of complete or removable partial dentures (α = 0.05). Certainty of the evidence was verified using the GRADE approach.

RESULTS

Eleven studies (seven RCTs and four N-RCTs) were included. The risk of bias was considered low for two studies, some concerns for five, and high for the last four studies. Meta-analyses showed that removable partial dentures with anatomic artificial teeth improved masticatory efficiency for carrot chewing (MD 6.31; 95% CI [3.39, 9.22], I2 = 0%). However, masseter and temporal muscle activities increased when removable partial dentures with nonanatomic teeth were used (MD -756.97; 95% CI [-892.25, -621.68], I2 = 100%). Masticatory ability was not influenced by occlusal morphology during chewing of all foods in complete denture users: Carrot (MD -0.88, 95% CI [-8.98, 7.23], I2 = 57%); sausage (MD -8.86, 95% CI [-23.05, 5.33], I2 = 71%); apple (MD -5.78, 95% CI [-28.82, 17.26], I2 = 87%); and cheese (MD -4.16, 95% CI [-15.14, 6.82], I2 = 62%). The certainty of evidence for all evaluated outcomes was very low, mainly due to very serious problems found in the parameters of inconsistency, indirectness, and imprecision.

CONCLUSIONS

Despite the very low certainty of evidence, the occlusal morphology of artificial teeth influences masticatory function. Anatomic teeth improved the masticatory efficiency and muscle activity of removable partial denture wearers. Nonanatomic teeth increased temporal and masseter muscle activity, which negatively affected chewing in removable partial denture users. However, patients using complete dentures with anatomic and semi-anatomic teeth presented similar masticatory ability.

What Occlusal Scheme Should Be Used with Removable Partial Dentures?

PURPOSE

Multiple clinical studies have been published comparing different philosophies of complete denture occlusion and different types of denture teeth. However, it is unclear whether comparable data are available for occlusal schemes used with removable partial dentures (RPDs). Therefore, this review investigated the dental literature related to occlusal schemes for RPDs.

MATERIALS AND METHODS

A PubMed search of English language articles was performed using the term "removable partial denture, occlusion" with 765 results. When the term "occlusion in removable partial prosthodontics" was used there were 784 results. Seventy-four articles were identified using the different search term of "RPD, occlusion" while use of the term "occlusal scheme, with removable partial dentures" listed 18 publications. The term "removable partial denture, occlusion, literature reviews" produced 38 potential publications related to the topic. Using the term "removable partial denture occlusion systematic review" resulted in 2 citations. Using the term "RPD occlusion literature review" resulted in one foreign language manuscript whereas using the term "RPD occlusion systematic review" resulted in one article unrelated to dentistry. The term "clinical studies of RPD occlusion" produced 5 results with none related to the topic. There were 23 results using the term "clinical studies of removable partial denture occlusion" with one potentially related to RPD occlusal schemes.

RESULTS

A review of the titles and abstracts revealed 12 articles that appeared to contain specific information about the occlusal scheme used with RPDs. Following a detailed review of those publications, only 4 contained recommendations for RPD occlusion and were included in this review. The available information regarding the recommendations for occlusal schemes in these articles was based on expert opinion. A decision was made to include a hand search of 9 textbooks containing varying amounts of information related to occlusal schemes for RPDs, but no evidence-based references related to RPD occlusal schemes were found in the textbooks. Since this entire review is based on expert opinion, no attempt was made to critique the opinions expressed by these authors but rather to present their perspectives for evaluation by readers.

CONCLUSIONS

The occlusion developed with RPDs should be physiologically harmonious, allowing the supporting structures to remain in a good state of health with functional stress distributed among all the occluding teeth. Multiple authors indicate the occlusion in maximum intercuspation/centric occlusion should incorporate bilateral posterior contacts with no deflective occlusal contacts. When most occlusal contacts on natural teeth are missing, it has been proposed that extension base RPDs have their occlusal contacts developed in centric occlusion. Regarding eccentric occlusal relationships, a balanced occlusal scheme has been recommended by multiple authors with one author advocating use of a lingualized balanced. An anterior guided (canine-protected) occlusion has also been recommended when the canines are present and not periodontally compromised. When RPDs oppose a complete denture, several authors indicate a bilateral balanced occlusion should be used to help stabilize the complete denture.

Service Evaluation of Recording Jaw Registrations for Removable Partial Dentures in NHS General Dental Practices

AIMS

To establish the prevalence of jaw registrations being taken for removable partial dentures (RPDs) in primary dental NHS practices.

METHOD

271 RPDs made by 16 general dental practitioners across four NHS dental practices were evaluated prospectively. The number of teeth replaced, whether jaw registration was undertaken, and the number of denture adjustment appointments were recorded. Telephone interviews with dental technicians were held to establish their preferred jaw registrations material.

MAIN FINDINGS

Jaw registrations were not carried out in 27% (n=72) of RPD. When jaw registration was recorded, 14% (n=28) required a further denture adjustment appointment. 64% (n=46) of dentures where jaw registration was not recorded required at least one further denture adjustment appointment. Dental technicians unanimously preferred a squash-bite wax block, with centre and canine positions marked and cast models secured with elastic bands.

CONCLUSION

Overall, recording a jaw registration reduced the number of denture adjustment appointments required.

Challenges in Treating the Class II Edentulous Patient

With a significant portion of edentulous patients presenting with a skeletal Class II relationship, specific denture needs for this patient group need to be considered. This paper examines the factors that need to be taken into account to prevent common problems from occurring when providing full dentures for a Class II edentulous patient.

Management of compromised ridges: a case report

Complete denture therapy is an age old form of dental treatment. Ridge atrophy poses a clinical challenge towards the fabrication of a successful prosthesis. Extreme resorption of the maxillary and mandibular denture bearing areas results in sunken appearance of cheeks, unstable and non retentive dentures with associated pain and discomfort. This article describes the step by step rehabilitation procedure of a patient with atrophic ridges using a hollow maxillary complete denture with cheek plumpers attached to it and the recording of neutral zone to ensure a stable mandibular denture.