Rehabilitation of biting abilities in patients with different types of dental prostheses

Four-year assessment of masticatory function in mandibular overdenture wearers: A randomised clinical trial comparing two to four implants to retain the prosthesis

BACKGROUND

Limited data exist on the mid- to long-term masticatory capacity of mandibular overdenture (IOD) wearers, particularly regarding the use of posterior implants to retention.

OBJECTIVES

To periodically evaluate mastication of IOD wearers, comparing the effectiveness of two to four implants to retain the prosthesis.

METHODS

In a randomised controlled clinical trial, 20 complete edentulous patients (14 women), aged 51-84 years (mean age 69.1 ± 9.6), received new bimaxillary complete dentures (CD). After adaptation, baseline measurements of masticatory performance (X50) and swallowing threshold were conducted using the sieving method. Patients were then randomly assigned to groups: control (two intra-foraminal regular implants) and experimental (two intra-foraminal regular implants and two extra-short posterior implants) (n = 10 each). After 4 months, implants were splinted, and a new mandibular IOD was fabricated with bar/clip retention. Mastication was reassessed after 6, 12, and 48 months, and data analysed with repeated measures ANOVA and Sidak's post hoc (α = 0.05).

RESULTS

Despite a loss of two patients per group, masticatory performance significantly improved after mandibular IOD installation (p = .031) in both groups (p = .670). A second improvement was observed after 6 months (p = .027), with no subsequent changes (p > .05). Swallowing threshold improvements were noted with IOD, and no discernible differences between groups were observed (p > .05).

CONCLUSION

Masticatory function significantly improved after mandibular IOD installation, with the number of implants demonstrating minimal influence.

CLINICAL TRIAL REGISTRATION

The present study was not registered in a public database, as mandated. It is important to note that the recommendation for registration was initiated in 2017 by the Committee of Medical Journal Editors, while patient inclusion in the research took place in 2016. Given that the data presented in this manuscript cover a follow-up period of up to 4 years post-surgical intervention, delayed registration was not feasible.

Impact of salivary flow inhibition on masticatory behaviours in healthy individuals

BACKGROUND

It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication.

OBJECTIVES

We aimed to clarify: (1) how hyposalivation affects jaw-closing and hyoid-elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food.

METHODS

Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation.

RESULTS

Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p = .011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p = .013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p < .001). Suprahyoid activity/cycle was significantly greater at the middle (p = .045) and late stages (p = .002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p = .043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p < .001).

CONCLUSION

Hyposalivation-induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition.

Functional oral status and oral health-related quality of life in community-dwelling older adults in Singapore

OBJECTIVES

The objectives were to investigate the association between oral functional status (defined by the number of functional teeth and functional occluding units [FOUs]) on oral health-related quality of life (OHRQoL). It also aimed to determine if dentures could compensate for the loss of FOUs in terms of OHRQoL in community-dwelling older adults in Singapore.

METHODS

Community-dwelling older adults, aged 60 years and above, were recruited from a community-based oral health functional screening programme from 1 May 2018 to 31 December 2019. During the screening, an Oral Health Impact Profile-14 (OHIP-14) questionnaire and oral examination were administered. Statistical analysis was performed using the chi-square test, univariate logistic regression and multivariate predictive modelling.

RESULTS

Data from 1037 participants were analysed (52% female; mean age 71.5 (SD 7.15)). The mean OHIP-14 score was 4.5 ± 7.2. The OHIP-14 scores were significantly associated with the number of functional teeth and the number of FOUs (p < .001). Having at least 20 functional teeth or 10 FOUs was associated with a significantly lower OHIP-14 score. Those with no FOUs had higher OHIP-14 scores compared to those with at least 10 FOUs, even in the presence of a satisfactory denture.

CONCLUSION

Maintaining at least 20 functional teeth or 10 FOUs was associated with better OHRQoL among community-dwelling older adults in Singapore. Dentures may have limited compensatory ability in terms of replacing natural functional occlusal units and maintaining OHRQoL.

Effect of different framework materials on stresses induced in distal extension removable partial dentures: A strain gauge analysis

PURPOSE

Evaluation of the strain transmitted to the abutments and residual ridge by polyetherketoneketone material compared to the cobalt-chromium one in distal extension removable partial dentures (RPDs) to fulfill the objective of preservation of the supporting structures.

MATERIALS AND METHODS

A virtual model simulating a Kennedy class I partially edentulous mandibular arch was designed. Two models, one for each group, were printed. Five RPDs were made in each group. In group CR, the framework was milled from a cobalt-chromium alloy. While in group PK, it was milled from a polyetherketoneketone blank. Strain gauge rosettes were bonded distal to the last abutment and posteriorly in the distal end of the residual ridge. Unilateral vertical and oblique loadings were applied. Mann-Whitney U test was used for inter-group comparisons while the Friedman test was used for intra-group comparisons and corrected by Wilcoxon Signed-Rank Sum. The significance level was set at p ≤ 0.05.

RESULTS

During unilateral vertical load application, a statistically significant difference was found between both groups distal to the abutment in the loaded and unloaded sides as well as the residual ridge on the unloaded side. During oblique load application, a statistically significant difference was found between both groups in all slots.

CONCLUSION

Polyetherketoneketone material induces less stress on the abutments and more stress on the residual ridges compared to the cobalt-chromium ones. Therefore, it may be recommended for weak abutments supporting RPDs.

Prospective evaluation of implants-supported, tooth-implant supported, and teeth-supported 3-unit posterior monolithic zirconia fixed restorations: Bite force and patient satisfaction

OBJECTIVES

This study aimed to evaluate the maximum bite force (MBF) and satisfaction of patients restored with implants, combined tooth-implants, and teeth-supported monolithic zirconia fixed dental prostheses (FDPs).

MATERIALS AND METHODS

Thirty partially edentulous patients in need of three units of FDPs in their mandibular posterior region were divided into three equal groups (n = 10) as follows: Group-1 patients received two implants for each at the second premolar and second molar regions, Group-2 patients received one implant for each at the second molar region, and Group-3 patients with missing lower first molar. All the restorations were constructed from monolithic zirconia. Patients were evaluated 1 week after placement of restorations (baseline) and then after 6, 12, and 24-month intervals for MBF using force transducer occlusal force meter and satisfaction (function, esthetic, and overall satisfaction) using a visual analog scale.

RESULTS

The mean MBF for Group 1 was higher than Group 2 (p = .044) but not that of Group 3 (p = .923). Additionally, Group 3 displayed a higher MBF than Group 2, although this difference was not statistically significant (p = .096). Concerning patient satisfaction, all study groups reported high levels of satisfaction across all satisfaction elements, and no significant differences were observed between the groups.

CONCLUSION

Within the limitations of this study, it can be concluded that Group 1 gives comparable anticipated treatment outcomes as Group 3 concerning biting force and patient satisfaction. However, Group 2 gives comparable satisfaction results with biting force value within the normal range; thus, it might be used as a treatment option in a specific situation.

Influence of risk factors on the long-term survival of oral rehabilitation with extra-narrow implants: a retrospective study

Objective

This study aimed to retrospectively collect clinical data to evaluate the influence of possible risk factors on the long-term success of implant treatment with extra-narrow (2.9 mm diameter) implants in a daily dental practice setting.

Methodology

Data were collected from records of patients who received at least one extra-narrow implant from 2012 to 2017, regarding implant survival, prosthesis survival, patient characteristics, and implant characteristics. The association between the dependent variables “implant survival”, “prosthesis survival,” and “adverse events” related to patient and implant characteristics was statistically evaluated by chi-square tests. Moreover, implant and prosthesis survival were analyzed by Kaplan-Meier survival curves.

Results

The sample was constituted of 58 patients (37 women and 21 men) with a mean age of 54.8 years old (SD: 12.5), followed up for up to eight years. In total, 86 extra-narrow implants were placed within this sample. Four implants were lost, resulting in an implant survival rate of 95.3%. A total of 55 prostheses were inserted and only one (1.8%) was lost, resulting in a prosthesis survival rate of 98.2%. The mean implant and prosthesis survival time was, respectively, 7.1 years and 6.3 years, according to the Kaplan-Meier survival analysis. A correlation was found between smoking and implant loss, which makes implant loss eight times more likely to occur in smokers than non-smokers. A significant association was also found between prosthesis loss and previous need of prosthesis repair. However, it was not considered clinically relevant. No association was found between the occurrence of adverse events and later implant or prosthesis loss.

Conclusion

High implant and prosthesis survival rates were found in the long term for treatment with extra-narrow implants. Moreover, a significant correlation between smoking and implant loss was observed.

Retrospective clinical study of tooth-supported single crowns: A multifactor analysis

The purpose of the study was to investigate the influence of multiple factors on the survival of tooth-supported single crowns and assess the biological and technical complications. This retrospective study included patients rehabilitated with single crowns with a minimum follow-up time of 6 months after delivery. The cumulative survival rate was calculated over the maximum period of follow-up time and reported in a life-table survival analysis. Univariate and multivariate Cox regression was used to evaluate the associations between clinical covariates and crown failure. The included cohort group consisted of 1037 single crowns delivered in 401 patients and followed for a mean of 134.8 ± 80.2 months. Cumulative survival rate was 89.9% and 80.9% after 5 and 10 years and 70.5% and 61.8% after 15 and 20 years, respectively. The main reasons for single crown failure were loss of retention, tooth loss, and fracture. Anterior placement, non-vital abutments, and bruxism significantly influenced the survival of single crowns. The survival of single crowns was not influenced by patient's age and sex, location of the crowns in relation to the jaws, type of tooth, presence of post and core, and type of crown material, treatment providers, or smoking. Anterior placement, non-vital abutments, and bruxism are factors suggested to increase the risk of single crown failure and the prevalence of technical and biological complications.

Can masticatory performance be predicted by using food acceptance questionnaire in elderly patients with removable dentures?

BACKGROUND

Although a food acceptance questionnaire is useful for subjective masticatory function assessments, its characteristics and limitations when applied to patients with removable dentures have been unclear. We therefore assessed the relationship between the subjective and objective masticatory function and explored whether or not a decreased masticatory function could be evaluated by food acceptance questionnaire.

METHODS

One hundred and nineteen patients >60 years old with removable partial and/or complete dentures participated. Food acceptance score (FAS) was calculated by using Sato's questionnaire with 20 food items. Masticatory performance (MP) was assessed by a visual scoring method using a test gummy jelly (UHA Mikakuto). Simple/multiple regression analyses were performed to explain the objective masticatory function. The cut-off value of FAS was determined to predict a decreased masticatory function by sensitivity, specificity and receiver operating characteristics curve.

RESULTS

No significant gender differences in MP or FAS were noted. Although both MP and FAS increased with the number of functional teeth, FAS was not significantly affected by age. The number of functional teeth, FAS and age had significant correlations with MP, with the number of functional teeth showing the strongest correlation. Multiple linear regression analyses identified the FAS as a significant explanatory variable for MP, and 70 was the optimal cut-off value for detecting a decreased masticatory function (MP score ≤ 2) in the diagnosis of 'oral hypofunction'.

CONCLUSIONS

Using FAS to assess the MP was deemed appropriate, and a score of 70 was the optimal cut-off value for detecting a decreased masticatory function.