Chewing efficiency, bite force and oral health-related quality of life with narrow diameter implants - a prospective clinical study: results after one year

Retention forces in mini-dental-implant retained mandibular overdentures: 10-year outcomes of a non-comparative longitudinal observational study

PURPOSE

To report the evaluation of in vivo retention forces after replacement of O-rings in one-piece mini dental implants (MDIs), retaining mandibular implant overdentures (IODs) with ball/O-ring attachments during 10 years assessed.

METHODS

Twenty patients received new complete dentures, which were converted into IODs through stabilization with four MDIs (Condent GmbH; diameter: 1.8 mm) placed in the interforaminal region. Retention forces were measured at the male and female parts at baseline, 5, and 10 years using a validated strain gauge. Fourteen patients completed the 10-year follow-up.

RESULTS

After 10 years, a minor but significant reduction in retention force was observed in the male part of the implant at position 44. In contrast, neither the male part at the other implant positions nor the female part at any position showed a significant decrease in retention force compared to baseline. After replacement of the O-ring inserts, baseline values could be restored and no significant changes in retention forces were observed at the 10-year follow-up. No difference in anterior and posterior implants could be determined.

CONCLUSIONS

Initial retention forces of mandibular IODs supported by four MDIs can be reestablished by replacing the O-rings with pristine ones after 10 years, with stable retention forces at both the male and female parts throughout the functional period, with no discernible differences between anterior and posterior implants.

A retrospective study on patient satisfaction and Oral Health-Related Quality of Life with fixed 4- or 6-implant supported prostheses over 3-7 years

OBJECTIVES

To compare patients' satisfaction and oral health-related quality of life (OHRQoL) in edentulous patients treated by All-on-4 and All-on-6 implant-supported fixed prostheses rehabilitation over 3-7 years.

METHODS

All patients (n = 125) were divided into short-term (3-5 years, n = 71) and long-term (5-7 years, n = 54) follow-up groups. Patients' satisfaction was examined in a cross-sectional survey. OHRQoL and psychological impact were evaluated using the Oral Health Impact Profile (OHIP). Comparison of All-on-4 and All-on-6, including OHIP values, satisfaction scores, treatment duration and complications, were analyzed using the Chi-square test and the Mann-Whitney U test. Potential influence of patient-related factors on patient-reported outcome measures (PROMs) were analyzed via the Mann-Whitney U test, the Kruskal-Wallis test and multiple regression analyses. Power calculation was conducted in R Studio.

RESULTS

Both All-on-4 and All-on-6 follow-up groups showed high scores in total satisfaction and PROMs, including chewing comfort, aesthetics, cleanability, and stability, with no significant difference (p > 0.05). Meanwhile, no significant differences were observed in the OHIP scores between two groups in both follow-up durations (p > 0.05). However, in patients with 3-5 years follow-up, All-on-4 group had significantly lower phonetic satisfaction scores than All-on-6 group (p < 0.05). Additionally, during both follow-up periods, All-on-4 patients exhibited notably superior psychological effect in contrast to All-on-6 patients (p < 0.05).

CONCLUSIONS

Edentulous patients treated by four or six implant-supported fixed prostheses showed same high satisfaction in oral health-related quality of life in both 3-5 years and 5-7 years follow-ups.

Mandibular overdenture retained by four one-piece titanium-zirconium mini implants: A 2-year RCT on patient-reported outcomes

AIM

The positive impact of implant interventions on dental patient-reported outcomes is an essential parameter of treatment effectiveness. This study assessed the 2-year changes in patient satisfaction and oral health-related quality of life (OHRQoL) of edentulous patients treated with a four mini implant mandibular overdenture (IOD) METHODS: The study was planned as a 2 × 2 factorial randomized clinical trial that tested two surgical approaches (flapped or flapless) and two loading protocols (immediate and delayed) using a titanium-zirconium mini implant (Straumann Mini Implant System®) and a PEEK retentive system (Straumann® Optiloc® Retentive System). Outcome measures (OHIP-Edent scores and the McGill Denture Satisfaction questionnaire) were assessed before treatment and at the 3-, 6-, 12-, and 24-month follow-ups. The Friedman test and multiple regression using Generalized Estimating Equations (GEE) were used for data analysis, considering the per-protocol (PP) and intention-to-treat (ITT) approaches RESULTS: Seventy-four patients were randomized to the study groups. No implant failure occurred during the study period. Marked improvement in all post-treatment periods compared to baseline were observed for the two outcomes. No significant effect of patient's gender, age, and surgical protocol on the study outcomes. The effect of treatment provision was significant for the two outcomes in the PP and ITT approaches (p < 0.001). A barely significant positive effect of the immediate loading was observed for OHIP-Edent in the PP approach (p = 0.020) CONCLUSION: IOD treatment significantly improved patient-reported outcomes measures, with sustained benefits over the two years of overdenture use, and can be considered a promising treatment option in for the edentulous mandible.

Mandibular overdenture with a single implant in the canine region (c-SIMO): a feasibility study

OBJECTIVES

The aim of this multi-center pilot study was to assess the viability and feasibility of a novel treatment concept - the canine-positioned single implant mandibular overdenture (c-SIMO), with the single implant placed on the patient's preferred chewing side instead of the midline.

MATERIALS AND METHODS

Participants received a single implant in the canine region of their preferred chewing side, based on an Asymmetry Index observed during mastication. The pre-existing mandibular denture was transformed into a c-SIMO on a spherical attachment. The primary outcome was oral health-related quality of life (OHRQoL), measured with GOHAI and OHIP-EDENT. Secondary outcomes included denture satisfaction index (DSI), chewing efficiency (CE), maximum bite force (MBF), implant survival and success, and prosthetic maintenance. Data analysis included descriptive statistics and bivariate comparison tests.

RESULTS

Fifteen participants received the c-SIMO treatment (mean age: 69.9 ± 7.0). Implant success and survival rates were 100% at 1 year. Patient-reported outcome measures improved significantly compared to pre-treatment values (OHIP-EDENT: p = 0.001; DSI: p = 0.001; GOHAI: p = 0.002). Masticatory outcomes also improved significantly (CE: p = 0.001; overall MBF: p = 0.005). Post-implant, MBF was significantly higher in the ipsilateral side compared to the contralateral side at 2 weeks (p = 0.019) and 3 months (p = 0.015), but no longer at T3 (p = 0.730). Common prosthodontic events included denture base adjustments (n = 17) and matrix activation (n = 9).

CONCLUSIONS

This pilot study concludes that c-SIMO is a promising treatment option, and a potential alternative to the single midline implant overdenture.

CLINICAL RELEVANCE

The novel treatment concept of a canine-positioned single implant mandibular overdenture could be a viable treatment alternative to the midline positioning.

One-Piece Mini Dental Implant-Retained Mandibular Overdentures: 10-Year Clinical and Radiological Outcomes of a Non-Comparative Longitudinal Observational Study

This study presents the first 10-year follow-up investigation of the implant survival and peri-implant outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone level alterations (ΔMBLs), clinical peri-implant parameters, and complications. Twenty participants with horizontally atrophied mandibles received complete dentures and four MDIs (diameter 1.8 mm) at baseline. The dentures were converted into IODs with O-ring attachments. The 10-year follow-up comprised a radiological assessment of ΔMBLs, peri-implant parameters, as well as biological and technical complications. Results from a 10-year follow-up of 14 participants showed a 100% implant survival rate for all 56 implants. The mean ΔMBL after 10 years was -1.12 ± 0.80 mm, with 49 implants classified as successful (ΔMBL < 2 mm) and 7 implants with satisfactory survival (ΔMBL 2-4 mm). Time after implant placement significantly influenced ΔMBL, with stable MBLs after 5 years. The prosthetic survival rate after 10 years was 93%. ΔMBLs were not influenced by implant position or gender but were significantly smaller in subjects older than 65 years. Conclusively, one-piece MDIs with O-ring attachments offer a reliable treatment option for horizontally atrophied mandibles after 10 years, with high implant and prosthetic survival rates, potentially benefiting from advanced age regarding peri-implant bone stability.

Small-diameter titanium grade IV and titanium-zirconium implants in edentulous mandibles: Ten-year results from a double-blind, randomised controlled split-mouth core-trial

The goal of this extension study was to compare the 10-year outcome of 3.3 mm diameter titanium-zirconium (TiZr) or grade IV titanium (Ti) implants in mandibular implant-overdentures.

MATERIALS AND METHODS

This study is the 10-year follow-up from a randomised, controlled, double-blind, split-mouth multicentre clinical trial. Patients with edentulous mandibles had received two implants in the interforaminal region (bone-level, diameter 3.3 mm, microrough surface), one of TiZr (test) and one of Ti (control). Implant survival and success, plaque and sulcus bleeding indices, probing pocket depth, gingival margin, clinical attachment level and radiographic crestal bone levels were evaluated.

RESULTS

Fifty of 91 patients with implants were available for the 10-year examination and 36 patients were valid for the intent-to-treat (ITT) analysis. The implant success rate was calculated as 94.6% and 91.9% for the TiZr implants and the Ti implants respectively. Four implants were lost (TiZr = 1; Ti = 3) in the entire study period. Kaplan-Meier survival analyses estimated 10- year implant survival rate for TiZr to 98.9% and Ti 95.8%.The mean of total and functional crestal bone loss was 1.49 mm (±1.37 mm) and 0.82 mm (±1.09 mm) in the TiZr group and 1.56 mm (±1.34 mm) and 0.85 mm (±1.16 mm) in the Ti group.

CONCLUSIONS

This split-mouth design RCT on mandibular implant-overdentures evidenced, bearing in mind its follow-up time-related reduced cohort size, high 10-year implant success- and survival rates. These results confirm TiZr as well-suited implant material for realising small-diameter implants. Registered on www.

CLINICALTRIALS

gov: NCT01878331.

Narrow-diameter versus regular-diameter dental implants for mandibular overdentures: A systematic review and meta-analysis

PURPOSE

The aim of this systematic review was to compare treatment outcomes in terms of implant survival rate, marginal bone loss, and patient-reported outcome measures (PROMs) between narrow-diameter implants and regular-diameter implants (RDIs) for mandibular implant overdentures (MIOs).

METHODS

This study was based on the methodology adapted as per Cochrane. Medline, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus were searched for pertinent studies published by July 22, 2022. Outcome parameters included in this meta-analysis were implant survival rate, marginal bone loss, visual analogue scale score for patient satisfaction, and value of oral health impact profile.

RESULTS

A total of 782 non-duplicate articles and 83 clinical study registrations were identified from database and hand searches, of which 26 were eligible for full-text searches. Finally, 12 publications reporting on 8 independent studies were included in this review. In the meta-analysis, implant survival rate and marginal bone loss did not significantly differ between narrow-diameter implants and RDIs. Regarding RDIs, narrow-diameter implants were associated with significantly better outcomes in general patient satisfaction and oral health-related quality of life than RDIs for mandibular overdentures.

CONCLUSIONS

Narrow-diameter implants have competitive treatment outcomes compared to RDIs in terms of implant survival rate, marginal bone loss, and PROMs. [Correction added on July 21, 2023, after first online publication: The abbreviation RDIs was changed to PROMs in the preceding sentence.] Thus, narrow-diameter implants might be an alternative treatment option for MIOs in situations with limited alveolar bone volume.

Evaluation of bite force, quality of life, and patients' satisfaction in elderly edentulous patients using implant overdentures

Purpose

This study aimed to compare the bite force (BF) between complete dentures and implant overdentures (IODs) retained by two mandibular implants. Additionally, we evaluated the quality of life (QoL) and patient satisfaction among individuals using IODs. In addition, the effects of demographic parameters such as age and sex, and clinical parameters such as implant length, implant diameter, attachment height, attachment color, and interimplant distance on BF, QoL, and patient satisfaction were evaluated.

Materials and methods

A total of 51 edentulous patients rehabilitated with the maxillary complete dentures and mandibular IODs retained by two implants were included in this study. BF was measured using a force meter pre- and post-implant in the same patients. Oral health-related quality of life (OHRQoL) was assessed with the Oral Health Impact Profile (OHIP-14) and patient satisfaction was assessed with the Visual Analog Scale (VAS) questionnaires.

Results

It was found that BF values were statistically higher for IODs than complete dentures (P < .001). In terms of attachment height of the OHIP scores, there was a significant difference in the psychological disability and social disability domains (P < .05). When examining the change in patient satisfaction as a function of sex, it was found that mandibular retention satisfaction differed significantly by sex (P < .05), but there was no significant difference in the other domains.

Conclusion

Within the limitations of this study, it was observed that the BF increased after the use of IODs. Several factors, including age, interimplant distance, attachment height, and attachment color, were found to impact OHRQoL. Sex and implant diameter were identified as factors affecting patient satisfaction.

Biomechanical comparison of different framework materials in mandibular overdenture prosthesis supported with implants of different sizes: a finite element analysis

BACKGROUND

The aim of this study is to evaluate the stresses on the supporting bone, implants, and framework materials under masticatory forces in mandibular overdenture prostheses modeled with different framework materials and different implant types, using the Finite Element Analysis (FEA).

METHODS

For the finite element modeling, two identical mandibular jaw models were created; one with two standard (diameter:4.1 mm/12 mm length) and the other with two mini-implants (diameter:2.4 mm/12 mm length) were placed in the canine teeth area. The polymethylmethacrylate (PMMA) denture was modeled upon them, supported by Cobalt Chromium alloy (CoCr), Poly-ether ether ketone (PEEK), and Zantex materials with framework. No framework was added as a control model; only PMMA overdenture prosthesis was modeled.

RESULTS

Regardless of the framework materials of the overdenture prostheses, the stress values ​​on mini-implants in all models yielded approximately two times higher results comparing to standard implants. More stress transmission was observed in the supporting bone and implants in the control prostheses and overdenture prostheses supported with respectively PEEK, Zantex, CoCr alloy frameworks, respectively. In the framework materials, more stress occurred on CoCr, Zantex and PEEK in that order.

CONCLUSION

In the light of this study, the use of mini-implants as an alternative to standard implants is not promising in terms of distribution and transmission of chewing stresses. As a framework material, standard rigid metal alloys were found to be more advantageous than polymer materials in terms of stress distribution.

Quantitative parameters of digital occlusal analysis in dental implant supported restorative reconstruction recent 5 years: a systematic review

OBJECTIVE

The aims of this systematic review were to evaluate the clinical masticatory performance of implant-supported restorations, observe the occlusal force changes in the distribution of the implant restoration and reveal the positive and negative contributing factors of implant design and components based on the outcomes of digital occlusal measurement.

MATERIAL AND METHODS

An extensive search was conducted through PubMed and CENTRAL to identify clinical trials on implant-retained restorations using digital occlusal analysis methods. Two researchers assessed the identified studies and data extraction independently, and the data synthesis strategies without meta-analysis that summarizes the effect estimates were adopted.

RESULTS

The search screened 3821 titles and abstracts, then full-text analysis for 26 articles was performed, and 14 studies were included in the quantitative synthesis. Four of six studies for implant-retained overdenture showed statistically significant improved bite force when immediate loading (p = .00045, .00005, .00055, and .00005, respectively), and no statistically significant results in the other two studies (p = .225, .371, respectively.) However, the results of the favoured intervention were not statistically significant (p = .104, .166, respectively) in two studies of single posterior implant restorations. In all three studies, the bite force distributed on the implant prostheses of partially fixed implant-retained restoration increased statistically significantly (p = .013, .001, .05, respectively).

CONCLUSIONS

The edentulous restoration supported by implants seems to significantly improves bite force and chewing efficiency compared with conventional dentures. Regular quantitative occlusal measurement is recommended to avoid the possible risk of overload. Smaller implants size and relatively small and flexible attachment designs may be more conducive to the stability and retention of the restoration of atrophy of alveolar bone.

Does the Length of Mini Dental Implants Affect Their Resistance to Failure by Overloading?

Objective: We aimed to evaluate the failure resistance of different lengths of mini dental implants from the same manufacturer, and to assess their failure following overloading. Materials and Methods: According to the ISO 14801, 15 mini dental implants 2.4 mm in diameter, with lengths of 8.5 mm, 10 mm, or 13 mm, were subjected to compression loading until failure using a universal testing machine. The mean load-to-failure values for each length of the mini dental implants were calculated and analysed using SPSS®, via one-way ANOVA (p < 0.05). Results: The mean load to failure for mini dental implants was 329 N (SD 6.23), 326 N (SD 5.95), and 325 N (SD 6.99) for the 13 mm, 10 mm, and 8.5 mm implants, respectively. A comparison of means showed no significant difference between the groups (p = 0.70). The tested mini dental implants exhibited bending failure modes below the first thread. Conclusion: Under high compressive loading testing, there was no effect of the length on the failure of the mini dental implants following overloading. Moreover, all tested mini dental implants with different lengths showed the same failure mode and distortion location.

The Effect of a Masticatory Muscle Training Program on Chewing Efficiency and Bite Force in People with Dementia

Until now, no study has investigated the effects of masticatory muscle training on chewing function in people with dementia. This study aimed to investigate whether physiotherapeutic exercises for the masticatory muscles have an influence on chewing efficiency and bite force in people with dementia. In a clinical trial with stratified randomization subjects were assigned to three groups based on the Mini Mental State Examination (MMSE: group 1—28–30, group 2—25–27, group 3—18–24). Each group was divided into an experimental (ExpG, intervention) and control group (ConG, no intervention). As intervention a Masticatory Muscle Training (MaMuT) (part 1: three physiotherapeutic treatments and daily home exercises, part 2: daily home exercises only) was carried out. Chewing efficiency and bite force were recorded. The MaMuT influenced the masticatory performance regardless of the cognitive state. Bite force increased in ExpG 1 and 2. Without further training, however, the effect disappeared. Chewing efficiency increased in all ExpG. After completion of the training, the ExpG 2 and 3 showed a decrease to initial values. Subjects of ExpG 1 showed a training effect at the final examination, but a tendency toward the initial values was observed. ExpG 3 seemed to benefit most from the physiotherapeutic exercises in terms of improving chewing efficiency by the end of the intervention phase. ExpG 1 showed the greatest gain in bite force. The MaMuT program is a potential method of improving masticatory performance in people with cognitive impairment or dementia when used on a daily basis.

Circumferential bone level and bone remodeling in the posterior mandible of edentulous mandibular overdenture wearers: influence of mandibular bone atrophy in a 3-year cohort study

OBJECTIVES

Evaluate circumferential bone level and morphological alterations in the posterior mandibular ridge of atrophic (AP) and non-atrophic (NAP) patients using implant-retained mandibular overdentures (MO) over 3 years.

MATERIALS AND METHODS

Twenty-six edentulous patients categorized according to mandibular atrophy (AP = 13/NAP = 13) received two narrow diameter implants (Facility, 2.9 × 10 mm) in the anterior region of mandible. The vertical and horizontal bone level was measured along with bone remodeling at 4 distances from the mental foramen in the posterior region of the mandible (L1-L4) via CBCT.

RESULTS

NAP showed significantly higher total height and medullary height in all posterior regions at 1 and 3 years (p ≤ 0.01). Cortical height and width were significantly higher (p ≤ 0.05) in this group at distances L1 and L4, respectively, in year 1. NAP shows a significantly higher % of medullary height at distances L1 (p ≤ 0.05), L2 (p ≤ 0.01), and L3 (p ≤ 0.05) after 1 year, and at all distances (p ≤ 0.05) after 3 years. Bone remodeling in the groups differed significantly (p ≤ 0.05) in terms of cortical width and % medullary width at L3.

CONCLUSION

AP and NAP showed similar vertical and horizontal bone level. Bone resorption in the posterior ridge was stabilized by MO over 3 years; however, AP are more susceptible to the long-term substitution of medullary bone by cortical bone.

CLINICAL RELEVANCE

This study is the first to longitudinally evaluate bone dimensions in atrophic and non-atrophic two-implant MO users by CBCT and revealed that MO is a predictable treatment based on the stabilization of the posterior bone resorption.

Impact of rehabilitation versus edentulism on systemic health and quality of life in patients affected by periodontitis: A systematic review and meta-analysis

AIM

To investigate the effect of rehabilitation in fully/partially edentulous patients with stage IV periodontitis on oral-health-related quality of life (OHRQoL) and systemic health.

MATERIALS AND METHODS

A systematic electronic and manual search was conducted. Three authors independently reviewed, selected, and extracted the data. Outcomes were OHRQoL (Oral Health Impact Profile 14 [OHIP-14] and OHIP-49, General Oral Health Assessment Index [GOHAI], visual analogue scale, symptoms registration) and systemic health-related outcomes (incidence and prevalence of systemic diseases, values of systemic disease indicators). Qualitative data were synthesized for OHRQoL and systemic health-related outcomes. Meta-analysis was conducted on available quantitative data.

RESULTS

The search identified 59 articles (6724 subjects in total). OHRQoL improved across all the studies, irrespective of the number of missing teeth, their location, or treatment modality. Meta-analysis showed significant improvement of OHIP-49 (36.86, p < .01) in manuscripts including subjects affected by periodontitis, consistently with the remaining literature (reduction of score points post rehabilitation: OHIP-14 = 10.52, OHIP-49 = 56.02, GOHAI = 5.40, p < .01 for all). Non-rehabilitated subjects exhibited inferior cognitive status, higher medication intake, and frailty. However, our data are limited and should be interpreted with caution.

CONCLUSIONS

Oral rehabilitation improves OHRQoL and, potentially, systemic health in edentulous patients. It is unclear whether these findings may be extrapolated to patients with stage IV periodontitis.

Oral diadochokinesis and associated oro-facial function in young and old German mother-tongue speakers: A cross-sectional study

Objectives

The aims of this study were to compare oral diadochokinesis and to test associations with oro‐facial functional parameters in healthy young and old German speakers.

Background

Oral diadochokinesis is a key component in the concept of oro‐facial hypofunction and relates to tongue and lip motor function but may depend on the linguistic background.

Materials and methods

Healthy German speakers with a minimum of 20 teeth were recruited to form a young (<60 years) and an older group (≥60 years). Oral diadochokinesis was assessed as the number of repetitions/s for the monosyllables /pa/, /ta/ and /ka/ to evaluate movement capacity of the lip, the anterior region of the tongue and the posterior region of the tongue, respectively. Maximum voluntary lip force, maximum voluntary bite force, masticatory performance, maximum voluntary tongue pressure, xerostomia and swallowing function were assessed with validated instruments. Results are presented as median (IQR).

Results

Sixty participants formed the younger group (n = 35, 30.0 years [24.0‐49.0]) and the older group (n = 25, 64.0 years [62.0‐72.0]). Counts/s of /ta/ were different between age groups (younger group: 6.0 vs older group: 5.4) but not for syllables /pa/ (younger group: 6.0 vs older group: 5.8) and /ka/ (younger group: 5.6 vs older group: 5.0). The oral diadochokinesis with /pa/ was overall associated with maximum voluntary lip force; oral diadochokinesis performed with /ta/ was associated with tongue pressure, and oral diadochokinesis with /ka/ with swallowing function. Masticatory performance was not associated with oral diadochokinesis but with maximum voluntary bite force, xerostomia and with maximum voluntary tongue pressure.

Conclusions

The published thresholds for oral diadochokinesis should be reconsidered in non‐Japanese mother‐tongue speakers. However, they still play an important role in the overall concept of oro‐facial functional assessment.

Treatment concepts of horizontally deficient ridges-A retrospective study comparing narrow-diameter implants in pristine bone with standard-diameter implants in augmented bone

OBJECTIVES

To compare clinical and radiological outcomes of narrow-diameter implants (NDI) placed in pristine bone to standard-diameter implants placed in combination with horizontal bone augmentation procedures (SDI+A) for horizontally deficient alveolar ridges.

MATERIAL AND METHODS

For this retrospective study, the outcome of 597 NDI (∅ 3.3 mm, 272 patients), inserted in pristine bone, were compared with 180 SDI (∅ 4.1 mm, 83 patients), inserted in combination with horizontal augmentation procedures. Oral health-related quality of life was assessed in patients available for recall.

RESULTS

After a mean follow-up of 37.6 ± 40 months for the NDI and of 42.4 ± 49 months for the SDI+A, survival rates were 96.1% for NDI and 95.6% for SDI+A. Cumulative 5-year and 10-year implant survival rates were 94.3% and 92.2% for the NDI group and 97.0% and 88.3% for the SDI+A group, indicating no significant difference (p = .89). According to the criteria of Buser et al., an implant success rate of 84.3% was obtained for the NDI and an implant success rate of 81.3% for the SDI+A (p = .79). Regarding oral health-related quality of life, a similar and high patient satisfaction could be observed in both groups.

CONCLUSIONS

NDI without augmentation procedures showed a similar clinical outcome as SDI in combination with augmentation procedures after a follow-up of more than 3 years. Therefore, NDI might be a reasonable alternative in cases of horizontal bone atrophy (no clinical trial registration as patient inclusion started 2003).

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.

Do implant-retained mandibular overdentures maintain radiographic, functional, and patient-centered outcomes after 3 years of loading?

OBJECTIVES

Analyzing whether radiographic, functional, and oral health-related quality of life (OHRQoL) outcomes are maintained over 3 years of implant-retained mandibular overdenture (IMO) function and investigating the bite force associations in the 3rd year of function.

MATERIAL AND METHODS

A longitudinal clinical study in which 24 IMO users were evaluated during a 3-year follow-up period. Patients' posterior area index, masticatory function, OHRQoL and bite force were assessed. The masticatory function parameter ST_X50 reflects the opening through which 50% of the crushed particles would pass, ST_B describes the homogeneity of the bolus, and the masticatory efficiency parameters ME_5.6 and ME_2.8 represent the % of material retained in the 5.6 and 2.8 mm sieves, respectively.

RESULTS

A significant increase in posterior area index (p ≤ .01) was found in all evaluated periods. Minor deteriorations in ST_X50 (p ≤ .01) and ME_5.6 (p ≤ .01) between the 2nd and the 3rd year coincided with improvements in ST_B (p ≤ .01), number of cycles (p ≤ .01), and cycle time (p = .02). The global OHIP-Edent score (p = .02) and the scores in the functional limitation (p = .02), psychological discomfort (p ≤ .01), and handicap domains (p ≤ .01) increased significantly between the 2nd and the 3rd year. Correlations between bite force and cycle time (p = .03) and between posterior area index and ST_X50 (p ≤ .01) and ME_2.8 (p = .02) were also found.

CONCLUSION

Changes in posterior area index, masticatory function, and OHRQoL are still ongoing during the 3rd year of IMO function. Bite force and posterior area index influence the masticatory function outcomes in the 3rd year of IMO function.

Computerised occlusal analysis of mini-dental implant-retained mandibular overdentures: A 1-year prospective clinical study

Occlusal analysis is a substantial tool for the functional improvement evaluation after using implant-retained overdenture comparing to complete denture without dental implant retaining. To evaluate occlusal pattern, chewing force distribution in mini-dental implant-retained mandibular overdentures by computerised occlusal analysis system and to compare patient satisfaction after 1-year function. Thirty-one patients wearing complete dentures were included in the study. Prior to mini-dental implant-retained treatment, all patients were assessed for occlusion and force distribution using computerised occlusal analysis system (T-Scan^® ), and then, all patients received two mini-dental implant-retained mandibular overdentures. Mini-dental implants were immediately loaded using low vertical profile attachments (Equator^® ). T-Scan^® was used to evaluate chewing force and force distribution at 1 day, 3 months, 6 months and 12 months. The patient satisfactions before implant placement and after 1 year were evaluated using questionnaires which included satisfaction of denture quality, psychosocial behaviour and chewing efficiency modified from the validated questionnaires. Clinical evaluation of two mini-dental implant-retained mandibular overdentures showed 100% success rate after 1 year. T-Scan^® demonstrated that maximum occlusal contact force increased continuously. The force distribution; the tooth contact number increased over the period. At 1-year follow-up, overall patient satisfaction was significantly greater than before receiving mini-dental implant treatment (P < .001). Using computerised occlusal analysis, mini-dental implants improve complete denture function significantly in terms of maximum occlusal contact force, tooth contact number without the impairment of force distribution. The oral function of the patients has been enhanced.

A novel method for assessing oral mixing ability based on the spatial clusters quantified by variogram

BACKGROUND

The two-colour chewing test (TCCT) has been widely used for assessing oral mixing ability, a critical component of masticatory performance. Most studies focused on quantifying the evenness of colour distribution. It remained unknown if the variation of colour clustering was a valid index of oral mixing ability.

OBJECTIVE

The study aims to investigate the oral mixing ability based on the spatial clusters quantified by variogram.

METHODS

Fifty older people (15 male/35 female, age: 66.0 ± 7.8 years) were assessed for the TCCT and the colour-changeable chewing gum test (CCGT). For the CCGT, we quantified the degree of colour change (ΔE). For the TCCT, the highest peak in colour histogram (HP), the standard deviation of colour values (SDC) and the range of variogram from colour spatial distribution (VARG) were quantified. The participants were grouped according to the contacts of posterior teeth, as assessed by Eichner Index (EI).

RESULTS

Highest peak, SDC and VARG showed statistically significant differences between the EI groups (two-tailed independent t test P < .05). Higher VARG (ie a lower degree of clustering) was significantly negatively correlated with ΔE (r = -.36, one-tailed P < .01). The binary logistic regression revealed that among the spatial indices (HP, SDC and VARG), only VARG achieved statistical significance in prediction to the EI group. Eliminating other indices was insignificant to the model performance.

CONCLUSIONS

Our results show that the averaged cluster sizes, quantified by variogram, are a valid index for quantifying the TCCT. Compared with other spatial indices, it had the best predictability to the condition of posterior contact.

Is one dental mini-implant biomechanically appropriate for the retention of a mandibular overdenture? A comparison with Morse taper and external hexagon platforms

STATEMENT OF PROBLEM

Limited information is available to clinicians on the use of dental mini-implants (MI) as opposed to standard-diameter implants (SDIs) for the stabilization of implant-retained mandibular overdentures (MOs).

PURPOSE

The purpose of this in vitro and finite element analysis study was to analyze and compare the biomechanical behavior of MOs with either 1 or 2 implants with external hexagon (EH), Morse taper (MT) SDIs, and MIs.

MATERIAL AND METHODS

Thirty photoelastic models (n=30) of each group (n=5) of SDIs (EH-1, EH-2, MT-1, MT-2) and MI (MI-1, MI-2) were fabricated for posterior, peri-implant, and total maximum shear stress evaluation by quantitative photoelastic analysis. One specimen of each group was further used to create the 6 computational models to be analyzed by finite element analysis. The maximum von Mises values and stress maps were plotted for each ductile component. Two types of load were applied to the overdenture: a150-N load bilaterally and simultaneously on the first molar and a 100-N load on the incisal edge of the central incisors at a 30-degree angle. The data were subjected to the 2-way ANOVA test and the Tukey honestly significant difference test (α=.05).

RESULTS

The EH-2 and MT-2 showed the lowest posterior (P<.001) and total (P<.05) mean shear stress values. For peri-implant shear stress, no difference was found among all groups (P>.05). Regardless of the loading area, the MI-1 and MI-2 groups showed the lowest von Mises stress values. However, for implant housing, the MI-1 group, under incisor loading, presented greater stress, followed by MT-1, EH-1, EH-2, MI-2, and MT-2. The attachment was the most overloaded structure, with high values under incisor loading, especially for the groups with 2 implants (MT-2, EH-2) as compared with the other models.

CONCLUSIONS

Biomechanically, regardless of the implant number, MI is a promising rehabilitation method with similar peri-implant shear stress and lower von Mises stress on the implant when compared with SDIs for MOs.

Clinical outcomes and bone-level alterations around one-piece mini dental implants retaining mandibular overdentures: 5-year follow-up of a prospective cohort study

OBJECTIVES

To report on the clinical outcomes of one-piece mini dental implants (MDIs) retaining mandibular implant overdentures (IODs), including marginal bone-level alterations (ΔMBLs), clinical peri-implant parameters, and technical- and biological complications during a 5-year follow-up. The null hypothesis was that ΔMBLs would be equal in subjects older than 65 years relative to younger subjects.

MATERIALS AND METHODS

Four 1.8-mm diameter one-piece MDIs with ball attachments were placed in the interforaminal region of 20 edentulous subjects. The existing complete dentures were converted to IODs. Standardized radiographs of each implant were taken at implant placement (baseline) and during the five-year follow-up. ΔMBLs and potential influencing factors were evaluated, and peri-implant parameters, and biological and technical complications were recorded.

RESULTS

The implant and prosthetic survival rates were both 100%. IODs fractured in seven participants. The overall mean ΔMBL after 5 years was -1.18 mm (standard deviation: 0.79 mm). ΔMBLs per month were most pronounced within the first 3 months after implant placement. ΔMBLs were not influenced by the implant location, the presence of keratinized mucosa, or gender. However, ΔMBLs were significantly smaller in subjects older than 65 years (p = .007).

CONCLUSIONS

One-piece MDIs retaining mandibular IODs with O-ring attachments are a predictable treatment option, providing stable peri-implant bone and soft tissue conditions over a mid-term follow-up. Incorporating a metal reinforcement can prevent denture fracturing when converting a complete denture into an IOD. The presence of keratinized mucosa does not necessarily lead to decreased bone-level changes. Advanced age might be beneficial in terms of peri-implant bone stability.

Evolution of in vivo assessed retention forces in one-piece mini dental implant-retained mandibular overdentures: 5-Year follow-up of a prospective clinical trial

BACKGROUND

The evolution of retention forces in one-piece mini dental implants (MDIs) retaining implant overdentures (IODs) is of major importance, as the male parts cannot be exchanged, due to the implant design.

PURPOSE

To report the evolution of retention forces of one-piece MDIs, retaining mandibular IODs with ball/ O-ring attachments during 5 years assessed in vivo.

MATERIALS AND METHODS

Four MDIs were installed in the interforaminal region and immediately loaded using the existing mandibular complete denture. Directly post-op, at the 1-year and the 5-year follow-up, the retention forces were assessed with a validated strain gauge at each implant site separately.

RESULTS

At the male part, changes could only be observed at implant site 34: During the first year, there was a statistically significant increase, whereas the retention forces were decreased at the 5-year follow-up. At the female part, retention forces decreased significantly over time. Baseline values could be reestablished by exchanging the O-rings. The changes of the retention forces were more obvious in the posterior, compared to the anterior implants.

CONCLUSIONS

Retention forces at the female part decrease significantly over time, when retaining mandibular IODs by MDIs with ball/ O-ring attachments. Baseline values can be reestablished by exchanging the O-rings. At the male part, changes of retention forces depend on the implant location.

A prospective cohort study on survival and success of one-piece mini-implants with associated changes in oral function: Five-year outcomes

OBJECTIVE

To investigate in a prospective cohort study the 5-year post-loading survival and success of one-piece mini dental implants (MDIs) in edentulous subjects with mandibular implant overdentures (IODs) and to report the associated changes of oral function with respect to patient age.

MATERIALS AND METHODS

Independently living edentulous patients were recruited and provided with new complete dentures. After an adaptation period, four one-piece MDIs (diameter 1.8 mm) were installed in the interforaminal region and immediately loaded. At baseline pre-operative (BL), as well as at 1-year and 5-year follow-up examinations, chewing efficiency was assessed with a validated color-mixing ability test and maximum voluntary bite force (MBF) was recorded with a digital force gauge. Implant survival and success were evaluated at 5-year follow-up. Non-parametric tests served to analyze the differences between time points.

RESULTS

Twenty patients participated in the study (5 men and 15 women; age at BL: n = 10 ≤ 65 years and n = 10 > 65 years). All patients were available for a 5-year follow-up (n = 2 in their long-term care facility; n = 1 only by telephone). The survival and success rates were both 100% after 61 ± 5.7 months. Chewing efficiency did not change over the first year (p = 0.167), but was improved at 5 year fup (n = 19) compared to baseline (p = 0.033) and to 1 year (p < 0.001). The MBF (n = 19 at 5-year follow-up) increased continuously over time (p < 0.001), but was less pronounced in the older cohort (p = 0.009).

CONCLUSIONS

Mini dental implants seem to be a successful treatment option for edentulous elderly patients with very high survival and success rates, and serve to improve long-term oral function.

Effect of implant-supported mandibular overdentures versus reline on masticatory performance and salivary flow rates in very old adults-A randomized clinical trial

PURPOSE

To compare the masticatory efficiency (ME), maximum voluntary bite force (MBF), masseter muscle thickness (MMT), and salivary flow rates (SFR) in completely edentulous dependent elders treated either with a conversion of their existing mandibular complete removable dental prostheses (CRDPs) into a two-implant overdenture (IOD) or a conventional reline of the CRDP.

MATERIAL AND METHODS

Participants were randomly allocated into intervention (IG) and control (CG) groups. The IG received two implants in the mandibular canine regions, and their CRDPs were transformed into IODs. The CG received a conventional reline of their mandibular CRDPs. Outcomes were recorded at each recall visit (baseline, immediately, 3 months, 12 months after intervention, and subsequently on an annual basis). Statistical analyses used mixed linear regression models (level of significance: p < 0.05).

RESULTS

The IG comprised 16 participants (age = 85.0 ± 6.2 years), while the CG comprised 16 (age = 84.8 ± 5.4 years), with a mean follow-up of 2.7 ± 2.2 years (range: 3 months-7 years). A significant increase of MBF in the IG was observed with an overall gain of 80 N (p < 0.001) compared with the reline group. There were no significant long-term changes in SFR, MMT, or ME within/between groups.

CONCLUSION

Since dependent elders with mandibular IODs present a significant gain in MBF, but no relative increase in SFR, MMT, and ME, it seems that this increased capacity of MBF is not exploited by the elders during their habitual chewing.

Implant-to-bone force transmission: a pilot study for in vivo strain gauge measurement technique

The experimental determination of local bone deformations due to implant loading would allow for a better understanding of the biomechanical behavior of the bone-implant-prosthesis system as well as the influence of uneven force distribution on the onset of implant complications. The present study aimed at describing an innovative in vivo strain gauge measurement technique to evaluate implant-to-bone force transmission, assessing whether and how oral implants can transfer occlusal forces through maxillary bones. In vivo force measurements were performed in the maxillary premolar region of a male patient who had previously received a successful osseointegrated titanium implant. Three linear mini-strain gauges were bonded onto three different buccal cortical bone locations (i.e. coronal, middle, apical) and connected to strain measuring hardware and software. A customized screw-retained abutment was manufactured to allow for vertical and horizontal loading tests. As to the vertical load test, the patient was instructed to bite on a load cell applying his maximum occlusal force for 20 s and then recovering for 10 s to restore the bone unstrained state; the test was repeated 20 times consecutively. As regards the horizontal load test, the implant was subjected to a total of 20 load applications with force intensities of 5 and 10 kg. During the tests, the recorded signals were plotted in real time on a graph as a function of time by means of a strain analysis software. The described strain gauge measurement technique proved to be effective in recording the forces transmitted from osseointegrated implants to the cortical bone. Horizontal loads caused higher deformations of cortical bone than vertical biting forces; in both situations, the deformation induced by the force transferred from the implant to the bone progressively decreased from the coronal to the apical third of the alveolar ridge. At approximately 9 mm from the implant neck, the effect of occlusal force transmission through osseointegrated titanium implants was negligible if compared to the apical region.

Validation of a purpose-built chewing gum and smartphone application to evaluate chewing efficiency

OBJECTIVES

To validate a purpose-built two-coloured chewing gum (Hue-Check Gum^® ), and to test the accuracy of a custom-built smartphone application for a colour-mixing ability test to assess chewing function.

METHODS

Fully dentate participants (28D-group) and edentulous participants with implant overdentures (IOD-group) were recruited. They chewed a Hue-Check Gum^® for 5, 10, 20, 30 and 50 chewing cycles, respectively. Maximum voluntary bite force (MBF) was assessed with a digital gauge. The specimens were analysed according to their colour mixture (variance of hue, VOH) with a validated software (VOH_scan) and a newly developed smartphone application (VOH_app).

RESULTS

Participants segregated by dental state were significantly different regarding the number of occluding pairs of teeth, age and MBF. VOH_scan showed a negative logarithmic association with the number of chewing cycles, and VOH could be predicted from chewing cycles, MBF and gender. The clearest discrimination between the IOD and the 28D groups was observed for n = 20 chewing cycles; at this point, VOH was distinguishably different with a P-value < 0.0001. The VOH_app was a very good predictor for VOH_scan with 0.80 < pseudo-R²  < 0.83, depending on light exposure and measuring distance. There was, however, a systematic error in the accuracy of the app for inadequately chewed specimens.

CONCLUSIONS

The use of the two-coloured chewing gum would provide a fast, simple and inexpensive method for the assessment of masticatory performance, which could be used in geriatric wards or in private practices without the requirement of specialised equipment or trained staff.

Implant Placement under Existing Removable Dental Prostheses and the Effect on Follow-Up and Prosthetic Maintenance

PURPOSE

The aim of this prospective clinical study was to compare the maintenance interventions required for solely implant-retained overdentures (I-OD) with that of overdentures retained by a combination of telescopic crowns and implants (T/I-OD).

MATERIALS AND METHODS

The participants in this study were 22 patients who initially presented either with a removable complete denture (n = 11) or with an overdenture retained by 1 to 2 telescopic crowns on natural teeth (n = 11). Subsequently, the total number of abutments was increased to 5 to 6 (maxilla) or 4 to 5 (mandible) by placing implants in strategically advantageous regions, generating two distinct groups: I-OD and T/I-OD. Ball attachments were connected to the implants and integrated into the existing denture. The maintenance aspects were analyzed according to the type of treatment (preventive, biological, and technical) and to the severity of treatment (minimal, moderate, and extensive).

RESULTS

During a mean observation time of 6.5 years, the tooth survival rate was 89% (T/I-OD) and the implant survival rate 100% (both groups). The survival rates of the overdentures ranged from 90.9% (I-OD) to 100% (T/I-OD). A mean number of 0.6 (I-ODs) and 2.0 (T/I-OD) treatments were performed for biological reasons; and 8.2 (I-ODs) and 9.6 (T/I-OD) for technical reasons, per patient, during the observation time. From biological aspects, significantly more extensive maintenance was found to be necessary in the T/I-OD group than in the I-OD group.

CONCLUSIONS

The therapeutic concept of implant placement under existing prostheses was promising when performed in indicated cases.

Long-term changes in oral health-related quality of life over a period of 5 years in patients treated with narrow diameter implants: A prospective clinical study

OBJECTIVES

The aim of this study was to assess long-term changes in oral health-related quality of life (OHRQoL) over a period of 5 years in patients treated with narrow diameter implants (NDI) in the mandible for support of an overdenture.

METHODS

In this prospective clinical study, a consecutive sample of 20 edentulous patients who had worn sufficient complete dentures for at least 12 weeks was provided with four immediately loaded one-piece titanium NDIs in the mandible. The German 49-item version of the Oral Health Impact Profile (OHIP) was applied to assess OHRQoL at baseline and all follow-ups (4 and 8 weeks, 3, 6, and 12 months, and 3 and 5 years after treatment was finished).

RESULTS

Before treatment, OHRQoL was substantially impaired indicated by high OHIP summary score (39.9 points). Four weeks after treatment, a substantial treatment-induced drop of OHRQoL impairment was observed (21.8 OHIP points), and at all follow-ups, OHIP scores were lower than at baseline (15.9-26.5 OHIP points; ANOVA: p<.001). Based on mixed-effect linear regression analyses, the treatment-induced effect on OHRQoL improvement over the entire study period was statistically significant for the OHIP summary scores as well as for all four OHIP domains: Oral Function, Orofacial Pain, Orofacial Appearance, and Psychosocial Impact (all: p<.001).

CONCLUSIONS

This study suggests that four immediately loaded NDIs for the support of conventional complete dentures in edentulous patients with substantially impaired OHRQoL may lead to a long-lasting treatment-induced improvement in OHRQoL.

CLINICAL SIGNIFICANCE

The provision of four NDI in the edentulous mandible is a promising treatment option for patients with substantial OHRQoL impairment and a positive attitude towards implant treatment. Furthermore, patients can be informed that improvements in OHRQoL are expected to last for at least 5 years.

The effect of DLC-coating deposition method on the reliability and mechanical properties of abutment's screws

OBJECTIVE

To characterize the mechanical properties of different coating methods of DLC (diamond-like carbon) onto dental implant abutment screws, and their effect on the probability of survival (reliability).

METHODS

Seventy-five abutment screws were allocated into three groups according to the coating method: control (no coating); UMS - DLC applied through unbalanced magnetron sputtering; RFPA-DLC applied through radio frequency plasma-activated (n=25/group). Twelve screws (n=4) were used to determine the hardness and Young's modulus (YM). A 3D finite element model composed of titanium substrate, DLC-layer and a counterpart were constructed. The deformation (μm) and shear stress (MPa) were calculated. The remaining screws of each group were torqued into external hexagon abutments and subjected to step-stress accelerated life-testing (SSALT) (n=21/group). The probability Weibull curves and reliability (probability survival) were calculated considering the mission of 100, 150 and 200N at 50,000 and 100,000 cycles.

RESULTS

DLC-coated experimental groups evidenced higher hardness than control (p<0.05). In silico analysis depicted that the higher the surface Young's modulus, the higher the shear stress. Control and RFPA showed β<1, indicating that failures were attributed to materials strength; UMS showed β>1 indicating that fatigue contributed to failure. High reliability was depicted at a mission of 100N. At 200N a significant decrease in reliability was detected for all groups (ranging from 39% to 66%). No significant difference was observed among groups regardless of mission. Screw fracture was the chief failure mode.

SIGNIFICANCE

DLC-coating have been used to improve titanium's mechanical properties and increase the reliability of dental implant-supported restorations.

How fast can treatment with overdentures improve the masticatory function and OHRQoL of atrophic edentulous patients? A 1-year longitudinal clinical study

OBJECTIVES

The aim of this prospective clinical study was to evaluate the masticatory function (MF) and subjective perception of patients with poor denture-bearing tissue in relation to change and the time required to identify an improvement in these parameters after rehabilitation with mandibular overdentures (MO) by two narrow-diameter two-piece implants.

MATERIAL AND METHODS

Twenty-three edentulous patients were selected for MO installation. The masticatory function (MF) was evaluated with the masticatory performance (MP) and swallowing threshold (ST) tests. In the MP test, each volunteer was instructed to masticate a portion of Optocal (standardized artificial test food) for 40 masticatory cycles. During the swallowing threshold test, the patients were instructed to chew a new portion of Optocal cubes until they felt the desire to swallow. The MF tests were performed while complete denture (CD) wearers (baseline) and 1, 3, 6, and 12 months after MO loading. In addition, the subjective perception was assessed through the questionnaires Dental Impact on Daily Living (DIDL), Geriatric Oral Health Assessment Index (GOHAI), and Oral Health Impact Profile in Edentulous (OHIP- EDENT) at the baseline and 3, 6, and 12 months after MO loading.

RESULTS

A significant improvement in masticatory function (p < .05) was observed already in the first month of loading. Three months after MO loading, a significant improvement (p < .05) was found in the subjective perception of patients. The effect size indicates that the MO had the greatest impact on the domains related to function and comfort of all questionnaires and in relation to psychosocial domain of the GOHAI. The level of patient satisfaction increased significantly after the MO loading and reached >90% satisfied patients at 12 months.

CONCLUSION

The MO improved both the MF of the patient and their oral health-related quality of life and satisfaction regarding the prosthesis in a short time period.

Predictive Parameters of Oral Health Quality of Life in Complete Mandibular Denture Wearers Stabilized by Mini-Implants: A Two-Year Follow-Up Study

The frequent instability of mandibular removable complete dentures affects patient Oral Health Related Quality of Life (OHRQoL). An innovative therapeutic strategy used to improve stability involves placing four symphyseal mini-implants. This study was aimed at assessing OHRQoL over time in subjects in which mini-implants were placed and exploring if certain parameters could predict the evolution of their OHRQoL. The Quality of life of subjects with dentures was assessed using the Geriatric Oral Health Assessment Index (GOHAI) before (T0), 2–6 months (T1), twelve months (T2) and twenty-four or more months (T3) after mini-implant setting. Age, gender and chewing ability were tested as explanatory variables for the change in OHRQoL with time. Thirteen women and six men were included (mean age: 69 ± 10 years). After mini-implant placement, mean GOHAI scores at T1, T2 and T3 increased significantly (p < 0.001). The GOHAI-Add mean score was not affected by age or gender. Baseline chewing ability impacted the “functional” and “pain and discomfort” fields of the mean GOHAI scores (p < 0.05). The OHRQoL was quickly improved after mini-implant placement in complete denture wearers and then stabilized over time. Baseline chewing ability can be used as a predictive parameter of OHRQoL.

Novel Low-Cost Sensor for Human Bite Force Measurement

This paper presents the design and development of a low cost and reliable maximal voluntary bite force sensor which can be manufactured in-house by using an acrylic laser cutting machine. The sensor has been designed for ease of fabrication, assembly, calibration, and safe use. The sensor is capable of use within an hour of commencing production, allowing for rapid prototyping/modifications and practical implementation. The measured data shows a good linear relationship between the applied force and the electrical resistance of the sensor. The output signal has low drift, excellent repeatability, and a large measurable range of 0 to 700 N. A high signal-to-noise response to human bite forces was observed, indicating the high potential of the proposed sensor for human bite force measurement.