Improvement and long-term stability of neuromuscular adaptation in implant-supported overdentures

Comparison of Man Hours Utilized for Mandibluar Overdenture Treatment Retained by Single Implant with Bar Fabricated by CAD-CAM Process and Conventional Casting Processs - An Vivo Study

Introduction

Both the population's average life expectancy and the number of patients without teeth are rising. A 2012 epidemiological survey in India found that 30% of the population is edentulous. The rehabilitation process with a set of removable maxillary and mandibular complete dentures is the standard treatment for patients who are edentulous. This study is the first to incorporate and compare a novel approach to a single implant-retained mandibular overdenture with a bar attachment fabricated by CAD-CAM and a casting process on a single implant in the symphysis region.

Method

Five maxillary and mandibular completely edentulous patients were enrolled in the study.

Results

Significant difference was seen in the conventional laboratory time and CAD-CAM time as P < 0.05.

Conclusion

Compared to the conventional casting process, the single implant-supported bar mandibular overdenture (SISBOD) with a novel bar required fewer man hours and was more convenient.

Assessment and Improvement of Masticatory Performance in Frail Older People: A Narrative Review

According to the World Health Organization (WHO), the estimated number of older adults is around 962 million and is projected to increase to 2.1 billion by 2050. The oral frailty concept is associated with gradual oral function loss in relation to aging. There is a need to emphasize the improvement of oral function based on an evaluation of masticatory performance in patients with various oral conditions or systemic diseases and especially in the frail elderly. The present narrative review presents an overview of the current state of the assessment and improvement of masticatory performance in frail older people. To fully encompass oral frailty, oro-facial hypofunction, or oro-facial fitness, dental Patient Reported Outcomes (dPROs) should be included; nevertheless, there are limited evidence-based rehabilitation approaches. The concept of oral frailty, oro-facial hypofunction, or oro-facial fitness should involve dental Patient Reported Outcomes (dPROs), and in this sense, there are only a few evidence-based rehabilitation procedures to improve oro-facial hypofunction besides prosthodontics. It must be considered that reduced neuroplastic capacity in old individuals might preclude a positive outcome of these strategies that might need to be accompanied by functional training and nutritional counseling.

Path pattern and movement during mastication on habitual and non-habitual chewing sides

PURPOSE

To clarify the presence or absence of differences in path pattern and movement during mastication between the habitual and non-habitual chewing sides.

METHODS

Participants were 225 healthy adults with natural dentition. Mandibular movement while chewing gummy jelly on each side was recorded, and masticatory path pattern was classified into five types (one normal and four abnormal). The frequency of each pattern was measured and compared between chewing sides. The amount, rhythm, velocity, and stability of movement and masticatory performance were measured and compared between chewing sides.

RESULTS

A normal pattern was observed on the habitual chewing side in 84.4% of participants. There was a significant difference between chewing sides in masticatory path pattern (χ² = 35.971, P < 0.001). Values of parameters regarding the amount and velocity of movement and masticatory performance were significantly higher on the habitual chewing side. Values of parameters regarding rhythm and stability of movement were significantly lower on the habitual chewing side.

CONCLUSION

The present findings of functional differences between chewing sides in terms of path pattern and movement during mastication suggest that these factors should be analyzed on the habitual chewing side.

Assessment of quality of life in total edentulous patients rehabilitated with implants and fixed prosthesis

Aim: Tooth loss is very prevalent in Brazil, reflecting high demand for dental services, especially those related to oral rehabilitation. This study aimed to assess the quality of life in total edentulous patients rehabilitated with implants and fixed prosthesis. Methods: Thirty-two patients were evaluated before and after rehabilitation with dental implants and fixed prosthesis using the OHIP-14 questionnaire and the Visual Analogue Scale (VAS) after 6 months follow-up. Results: OHIP-14 revealed a significant improvement after treatment in all seven parameters and in the global score (P < 0.001). VAS presented positive results related to patient satisfaction regarding oral rehabilitation, except for the hygiene of the fixed dentures. Conclusion: At the end of this study, OHIP-14 scores decreased by 50% in most of the questions raised, and VAS presented positive results, except for hygiene of the fixed dentures, presenting an improvement in the quality of life of total edentulous patients after rehabilitation with implants and fixed prosthesis.

Stability of masticatory movements after placement of implant-supported denture

The purpose of this study was to clarify the stability of masticatory movement after placement of implant-supported denture. Fourteen patients (patient group) with mandibular implants denture and maxillary complete denture and 30 dentate adults (control group) were asked to chew a boiled fishpaste, and the masticatory movement was recorded using MKG. For the 10 cycles beginning with the 5th cycle of mastication, the parameters representing the stability of masticatory movement were calculated. Data collected at 1, 3, 6, 9 months and 1, 2, 3 years after insertion of implants denture were compared between sessions and also between the patient and control groups. The mean and standard deviation of the values in the patient group at 1 month after insertion of implants denture were large, but gradually decreased 6 to 9 months after insertion of implants denture. Each parameter maintained almost the same value from 1 to 3 years. The parameter values of the patient group were significantly larger than those of control group from 1 to 9 months after insertion of implants denture, but 1 year after insertion of implants denture, there was no significant difference between the two groups in 5 out of 7 parameters. From these results, it was suggested that a certain duration, about 9 months to 1 year, was necessary for patients with implants denture to adapt to the new masticatory function and that the timing of functional evaluation should be set to 1 year after insertion of implants denture.

Masticatory performances and maximum occlusal forces of immediate and conventional loaded two-implant supported overdentures retained by magnetic attachments: preliminary study of randomized controlled clinical trial

Background

The appropriate loading protocol to improve masticatory performance (MP) is still unclear in elderly patients and two-implant overdentures (2-IODs) wearers. This study aimed to compare the long-term MP and maximum occlusal force of immediate loading (IL) and conventional loading (CL) of 2-IODs retained by magnetic attachments. Nineteen edentulous patients were randomly assigned to either an IL (n=10) or CL group (n = 9). In the IL group, the implant was loaded on the same day as insertion, whereas it was loaded 3 months after insertion in the CL group. Magnetic attachments were used to retain all overdentures to the implants. MP, measured by a piece of color-changeable chewing gum and a gummy jelly test, and maximum occlusal force, measured using an occlusal force measuring device, were assessed in both groups at baseline and at 3-, 4-, and 5-year follow-ups.

Results

No significant differences were observed in the MP and the maximum occlusal force between the IL and CL groups at any time point. However, a significantly higher MP was observed at the 3-year time point in the IL group (P = 0.036). The maximum occlusal force revealed a significant correlation with MP, both with the color-changeable chewing gum and gummy jelly at 5 years.

Conclusion

After long-term observation, no significant differences in MP and maximum occlusal force were observed between the IL and CL groups. However, compared to pre-implant insertion of the complete denture, the MP in the IL group significantly improved at 3 years. Furthermore, the maximum occlusal force was significantly correlated with MP at 5 years.

Trial registration

UMIN, UMIN000009889. Registered on 28 January 2013.

Long transmaxillary implants improve oral health-related quality of life of patients with atrophic jaws-a case series

Background

The advancement of contemporary dentistry is related to the improvement of existing techniques, materials, and technology, consistently for improving people’s oral health, which can ultimately reflect better quality of life. This study aimed to evaluate the oral-health-related quality of life (OHRQoL) of patients with atrophic jaws, who reported for the placement of long transmaxillary implants and posterior prosthetic rehabilitation. Twelve patients (n = 12), of both sexes, with a mean age of 55.83 ± 2.78 years, who were unable to receive conventional implants immediately because of lack of bone, received two long transmaxillary implants in a horizontal position, anteroposteriorly, one on each side, from the canine pillar to the maxillary tuberosity. After 6 months, the conventional clinical sequence for fabricating a fixed prosthesis type protocol or removable prosthesis type overdenture (MK1® system) was performed, when required to recover the lip volume. The Oral Health Impact Profile questionnaire (OHIP-14) was applied preoperatively and 6 months after rehabilitation using a prosthesis on the implants. The results were statistically analyzed using a significance level of 0.05.

Results

An improvement in the perception of OHRQoL was observed between the pre- and postoperative periods in the OHIP-14 total score and the domains related to functional limitation, physical pain, psychological discomfort, psychological disability, social disability, and handicap (p < 0.05).

Conclusion

It may be concluded that transmaxillary implant rehabilitation improves the OHRQoL.

Influence of Facial Morphology on Masticatory Function and Quality of Life in Elders Using Mandibular Overdentures: 3-Year Results

Background: Facial types may interfere in the oral health-related quality of life (OHRQoL) and masticatory performance of implant-retained mandibular overdenture (IMO) wearers.

Purpose: Investigate the medium-term changes in the masticatory function (MF) and OHRQoL parameters of IMO users, as a function of facial pattern, anteroposterior skeletal discrepancy, and sex.

Methods: Forty IMO users, most of them Caucasian (90%) with average age of 69.17 years were classified according to their facial pattern and antero-posterior discrepancy prior to rehabilitation. MF was evaluated by the multiple sieves method to determine the average particle size (X50), heterogeneity (B) and masticatory efficiency (ME, calculated as the percentage of material retained in the 5.6 and 2.8 mm sieves), using Masticatory performance (MP) and swallowing threshold (ST) tests. OHRQoL was measured by applying the dental impact on daily life (DIDL) questionnaire. The data were analyzed by Wilcoxon-paired tests to analyze changes in MF parameters over time, and mixed-effect multilevel regression models were employed to verify differences between groups.

Results: Significant changes were still observed in the 3rd year for the ST test with improvements in B for Mesofacial and in time for Dolichofacial individuals, while ME_2.8 deteriorated for Brachyfacial participants. B values of Class I and male individuals improved and brachyfacial individuals still presented worse homogenization (B) than Mesofacial participants in both masticatory tests. Class II and III participants still showed improvements in ME_5.6 and time compared to Class I despite increases in X50. Class II individuals needed less cycles than Class I in the 3rd year. Brachyfacial participants scored lower in the Appearance domain than Mesofacial ones in the 3rd year. Dolichofacial participants and Class III patients scored lower in the Oral Comfort domain than Mesofacial and Class I, respectively. In addition, age influenced the Pain, Oral Comfort and General Performance domains in the 3rd year.

Conclusions: Differences in facial morphology continue to influence the MF and OHRQoL outcomes in the 3rd year, and age influenced some OHRQoL domains. Brachyfacial individuals continue to benefit least from rehabilitation with IMO according to masticatory parameters.

Patient-reported outcome measures of edentulous patients restored with single-implant mandibular overdentures: A systematic review

AIM

To review the literatures concerning the effect of the single-implant mandibular overdenture (SIMO) on patient-reported outcome measures (PROMs) and masticatory function in the fully edentulous patients.

MATERIALS AND METHODS

Electronic databases (PubMed, Cochrane Library, EMBASE and Web of Science) were searched, complemented with manual resources. Prospective studies published in English up to February 2020 reporting the effect of SIMO on PROMs and masticatory function in the edentulous patients were included. This review focused on oral health-related quality of life (OHRQoL), satisfaction and masticatory function outcomes.

RESULTS

Of 1157 initially screened articles, 9 randomised controlled trials (RCTs) and 8 prospective studies involving 551 subjects fulfilled the inclusion criteria. Two RCTs were graded as high risk of bias or some concern, while others were low risk. All prospective studies had adequate representativeness and assessment, but only one study had a controlled cohort. In general, the edentulous patients restored with SIMOs had improved OHRQoL and general satisfaction compared to those with conventional complete dentures (CCDs), but the outcome of masticatory function was controversial. Compared with two-implant mandibular overdenture (TIMO), SIMO showed no significant differences regarding general satisfaction and satisfaction with speech, comfort, chewing ability, aesthetics and social life. Conflicting results were observed in OHRQoL and satisfaction with retention and stability. Better masticatory performance was observed in TIMO group than SIMO group.

CONCLUSION

Within the limitation of this review, SIMO is featured with better OHRQoL and satisfaction than CCD. SIMO and TIMO rendered similar patient satisfaction, but TIMO had better masticatory performance.

Evaluation of Bite Force and Masticatory Performance: Complete Denture vs Mandibular Overdenture Users

This cross-sectional observational study with 24 patients evaluated differences in bite force (BF) and masticatory performance (MP) between conventional complete denture (CCD) and implant mandibular overdenture (IMO) users and the correlation between these variables. The BF test was performed bilaterally with an occlusal force device. During the MP test, patients were asked to chew Optocal particles for 40 cycles. The Shapiro Wilk test was employed to verify the normality of the data, the student t test to identify differences between groups, and Pearson's correlation to investigate interrelationships between variables. A multiple linear regression was subsequently performed via the stepwise method. P values ≤0.05 were considered statistically significant. Unlike IMO users, CCD users presented a significant difference (25.6%) in BF between the dominant and non-dominant chewing side (p=0.04). IMO users presented significantly higher BF (p=0.01) without presenting a dominant side (p=0.38), and also performed significantly better for the following MP parameters: MPX50 values decreased by 27.25% in IMO users (p=0.01), MPB decreased by 48.38% (p=0.01), and ME 5.6 decreased by 53.25% (p=0.02), while ME2.8 increased by 151.57% (p=0.01). The BF and MPX50 in the IMO wearers group were negatively correlated (-0.57; p=0.05); this correlation coefficient was the only parameter included in the multivariate regression model. IMO users have higher BF and better masticatory performance than CCD users, especially in terms of chewed particles size reduction. MP is correlated with a higher BF in IMO users through better particle trituration.

Masticatory Adaptation to Occlusal Changes

This review deals with the frequent wide variability of masticatory capacity/incapacity. Neither researchers nor clinicians have taken sufficient account of this variability despite its implications for nutrition. Mastication in normal healthy oral conditions is first described, followed by a short presentation of the mechanisms of masticatory adaptation in the nervous system. Capacity, incapacity, and successful compensatory adaptation of mastication are then defined, along with the different methods used for their evaluation. Examples of adaptation needs are given, such as those concomitant with dental wear or occlusal changes. Finally, given its vital importance for deeply impaired mastication/deglutition function, the impact of masticatory adaptation processes on nutrition is examined.

Clinical evaluation of inter-implant distance influence on the wear characteristics of low-profile stud attachments used in mandibular implant‑retained overdentures

Background

This study was aimed to evaluate the influence of inter-implant distance on the wear characteristics of low-profile stud attachments used in mandibular implant retained overdentures.

Material and Methods

Forty Completely edentulous participants aged between 50 - 70 years were enrolled in this study. Each patient received 2-implants by 2-stage submerged surgical protocol. Participants categorized into 4-groups. Group I: 19 mm inter-implant distance with Locator retained overdentures; Group II: 19 mm inter-implant distance with OT Equator retained overdentures; Group III: 25 mm inter-implant distance with Locator retained overdentures; Group IV: 25 mm inter-implant distance with OT Equator retained overdentures. The female housings of each attachment were picked up to the mandibular overdenture. 12 month later the male inserts were replaced by new one. The used retentive male inserts were examined by Stereomicroscopic.

Results

Stereomicroscopic examination revealed wear were detected on both inner surface and, the core of male inserts. Comparison between the unused and the used Locator and OT equator retentive male inserts at various inter-implant distance revealed highly significant wear changes between them at either 19 mm, or 25 mm inter-implant distance P1= .000, P2=.000 respectively.

Conclusions

After one year of implant overdenture clinical use; both locator and OT equator retentive male inserts revealed significant surface deformities and wear. Wear were more notable on both locator and OT equator retentive male inserts with 25 mm interimplant distance than with 19 mm interimplant distance. Key words:Inter-implant distance, attachments wear, locator retentive male inserts, OT equator retentive male inserts.

Short-term follow-up of masticatory adaptation after rehabilitation with an immediately loaded implant-supported prosthesis: a pilot assessment

Background

When teeth are extracted, sensory function is decreased by a loss of periodontal ligament receptions. When replacing teeth by oral implants, one hopes to restore the sensory feedback pathway as such to allow for physiological implant integration and optimized oral function with implant-supported prostheses. What remains to be investigated is how to adapt to different oral rehabilitations.

The purpose of this pilot study was to assess four aspects of masticatory adaptation after rehabilitation with an immediately loaded implant-supported prosthesis and to observe how each aspect will recover respectively.

Methods

Eight participants with complete dentures were enrolled. They received an implant-supported acrylic resin provisional bridge, 1 day after implant surgery. Masticatory adaptation was examined by assessing occlusal contact, approximate maximum bite force, masticatory efficiency of gum-like specimens, and food hardness perception.

Results

Occlusal contact and approximate maximum bite force were significantly increased 3 months after implant rehabilitation, with the bite force gradually building up to a 72% increase compared to baseline. Masticatory efficiency increased by 46% immediately after surgery, stabilizing at around 40% 3 months after implant rehabilitation. Hardness perception also improved, with a reduction of the error rate by 16% over time.

Conclusions

This assessment demonstrated masticatory adaptation immediately after implant rehabilitation with improvements noted up to 3 months after surgery and rehabilitation. It was also observed that, despite gradually improved bite force in all patients, masticatory efficiency and food hardness perception did not necessarily follow this tendency. The findings in this pilot may also be used to assess adaptation of oral function after implant rehabilitation by studying the combined outcome of four tests (occlusal contact, maximum bite force, masticatory efficiency, and food hardness perception).

Electromyography evaluation of masseter and temporalis, bite force, and quality of life in elderly patients during the adaptation of mandibular implant-supported overdentures

OBJECTIVES

The aim of this study was to investigate the outcomes of the installation of two implant-supported overdentures until such treatment is complete. Although this treatment is well established in the literature, there are no studies comparing what happens to muscles and the quality of life (QoL) of patients during the treatment.

METHODS

We selected 13 completely edentulous patients, according to inclusion and exclusion criteria, to rehabilitate with mandibular overdentures retained by two dental implants and a complete denture as antagonists. We evaluated the efficacy of the treatment and its evolution in five steps: (i) initially, with the old complete dentures, (ii) after the implants' placement with the mandibular prosthesis relined, (iii) after the placement of the healing abutments, (iv) after the installation and adaptation of new prostheses, and (v) after a 3-month follow-up period. At each stage, we evaluated patients via temporal and masseter electromyography (EMG), molar and incisive bite force, and QoL.

RESULTS

The results for EMG found a decrease in muscle activity during rest, the mastication of raisins, and lateral movements when the overdentures were installed. For the bite force and QoL, there was a gradual improvement from the placement of the healing abutments period (P ˂ 0.05), which was sustained until the follow-up.

CONCLUSIONS

Comfort and stability improved during the treatment, demonstrated by the QoL and bite force results. These results are positive for elderly patients who might refuse an implant-supported overdenture due to treatment length.

An in vitro comparative study to evaluate the retention of different attachment systems used in implant-retained overdentures

Aim:

The aim of this in vitro study was to compare the change in the retentive force and removal torque of three attachment systems during simulation of insertion-removal cycles.

Methodology:

Edentulous mandibular models were made with heat-cured polymethyl methacrylate resin. Two implant replicas (CMI), of 3.75 mm diameter and 10 mm length, were placed in the intraforaminal region. Acrylic resin mandibular overdentures were fabricated and provision was made to receive three different overdenture attachment systems, prefabricated ball/o-ring attachment (Lifecare Biosystems, Thane, India), Hader bar and clip attachment (Sterngold, Attleboro, MA), and Locator^® implant overdenture attachment stud type (Zest Anchors LLC, USA). Using a universal testing machine, each of the models were subjected to 100 pulls each to dislodge the overdenture from the acrylic model, and the force values as indicated on the digital indicator were tabulated both before and after thermocycling (AT).

Statistical Analysis Used:

Statistical analysis comprised Kolmogorov–Smirnov test, Friedman test, and Wilcoxon signed ranks test.

Results:

The statistical model revealed a significantly different behavior of the attachment systems both before and AT. The ball/o-ring and bar attachments developed higher retentive force as compared to the locator attachment. The bar and clip attachment exhibited the highest peak as well as the highest mean retention force at the end of the study. The Locator^® attachment showed a decrease in retentive potential after an early peak.

Conclusions and Clinical Implications:

The ball/o-ring and bar and clip attachments exhibit higher retentive capacities than the Locator^® attachment over time.

Quality of Life of Patients Treated With Implant-Supported Mandibular Overdentures Evaluated With the Oral Health Impact Profile (OHIP-14): a Survey of 58 Patients

Objectives

The purpose of this study was to evaluate the oral health-related quality of life of patients treated with implant-supported mandibular overdentures and to compare the attachment systems used.

Material and Methods

Altogether 112 patients treated with implant-supported mandibular overdentures in 1985 - 2004 were invited to the follow-up; 58 of them attended and replied to the Oral Health Impact Profile (OHIP-14) -questionnaire. There were 48 overdentures with a bar connection and 10 with a ball connection, the total number of implants installed and still in use was 197. The mean follow-up time was 13.7 years. The associations between the OHIP-14 variables and the patient's age, gender as well as the number of implants supporting the overdenture and the type of attachment used were assessed.

Results

The results showed that patients with implant-supported mandibular overdentures were satisfied with their oral health-related quality of life (OHRQoL). Older patients were more satisfied than younger ones in both genders. Neither the implant connection type nor the number of supporting implants seemed to have a significant influence on the OHRQoL.

Conclusions

Especially older patients with mandibular implant-supported overdentures were satisfied with their oral health-related quality of life. Attachment type or the number of supporting implants did not have a significant influence on the oral health-related quality of life.

Changes in mastication after an immediate loading implantation with complete fixed rehabilitation

OBJECTIVE

This study aimed to measure modifications of mastication after immediate loading full-arch prosthesis (ILFAP) rehabilitation.

MATERIALS AND METHOD

Fourteen patients were observed before and 6 months after ILFAP rehabilitation when masticating two natural, standardized foods (peanut and carrot) and three model foods with increasing hardness. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Chewing time (CT), number of chewing cycles (CC), and chewing frequency (CF) were video recorded. A self-assessment questionnaire for oral health-related quality of life [Geriatric Oral Health Assessment Index (GOHAI)] was also used.

RESULTS

After ILFAP rehabilitation, the mean D50 values for carrot and peanuts were smaller [Repeated Model Procedures (RMP), F = 41, p < 0.001]. Mean CT and CC values recorded with the three model foods decreased, while CF increased regardless of the model food hardness (RMP, F = 14, F = 10, and F = 11, respectively, p < 0.001). The GOHAI score increased from 43 ± 9 to 56 ± 3 (t test, p < 0.001).

CONCLUSION

ILFAP rehabilitation improves the ability to reduce the bolus particle size and the ability to discriminate between different food hardnesses in the 6 months post-surgery period.

CLINICAL RELEVANCE

This study encourages the clinical development of immediate loading implantation with a fixed full-arch prosthesis protocol.

The influence of implant number and attachment type on maximum bite force of mandibular overdentures: a retrospective study

AIM

Assessment of the influence of such factors as attachment type, number of implants, gender and age of patients on maximum bite force (MBF).

MATERIAL AND METHODS

Sixty-two edentulous patients (32 females, 30 males; aged 64.03 ± 10.07 years, range 42-90 years) with mandibular implant overdentures with various attachment types were included in the study and their MBFs were recorded. The results were evaluated statistically at a significance level of p < 0.05.

RESULTS

The MBF in male patients was found to be statistically significantly (p < 0.05) higher than in female patients. No statistically significant differences (p > 0.05) were found with respect to age groups, attachment types and number of implants supporting the mandibular overdentures.

CONCLUSION

Within the limitations of this study, it is concluded that independent of the number applied, dental implants increase MBF in edentulous patients. While males show higher bite force, patient age and attachment type seem not to play an important role.