Maximum bite force following unilateral fixed prosthetic treatment: a within-subject comparison to the dentate side

Masticatory performance with one missing molar

PURPOSE

This study aimed to evaluate masticatory performance in cases where one molar was missing.

METHODS

Participants were 156 adults with one molar missing from their natural teeth, who were divided into group A (without prosthetic treatment) and group B (with prosthetic treatment). The non-missing side was designated as A1 or B1, and the missing side was designated as A2 or B2. The amount of glucose eluted (AG) when the participants chewed a gummy jelly was measured and used as a parameter for masticatory performance. AG was compared between the non-missing side (A1, B1) and missing side (A2, B2), and between the first molar missing group and second molar missing group.

RESULTS

AG was significantly greater on the dentate side (P < 0.001) and was significantly less in the A2 group when the first molar was missing (P = 0.002). The rate of decrease of AG was 11.1%, 14.3%, and 8.4% in groups A+B, A, and B, respectively.

CONCLUSION

Masticatory performance appears to decrease even with only one missing molar. Although improvement is achieved by prosthetic treatment, performance remains inferior to that on the dentate side.

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.

Effect of botulinum toxin A on pain, bite force, and satisfaction of patients with bruxism: A randomized single-blind clinical trial comparing two protocols

Purpose

The current study aims to evaluate bite force, perception of orofacial pain, and treatment satisfaction of patients with bruxism using two protocols of botulinum toxin A (BTX-A) injections.

Material and Methods

Two groups of patients seeking bruxism treatment and presenting bilateral orofacial pain of muscle origin were randomly created according to BTX-A injection sites: masseter muscle only, bilaterally (3 points in each muscle, 10 U per point), and masseter and temporal muscles (3 points in each masseter muscle and 2 points in each temporal muscle, 10 U per point). The patients were evaluated preoperatively and longitudinally at 15, 90, 120, and 180 days by the use of visual analog scales for pain and treatment satisfaction and a gnathodynamometer for bite force recording.

Results

The final sample included 10 participants in each group. Both groups presented mitigation of pain at 15, 90, 120, and 180 days in comparison with baseline; however, reduction in the posterior bite force was noted only at 15, 90, and 120 days. Quite high treatment satisfaction was reported from both groups at 15, 90, 120, and 180 days. No differences were observed between the groups in all evaluations and study periods.

Conclusion

In general, considering pain relief, reduction in bite force, and treatment satisfaction, both protocols of BTX-A seem to be somewhat equally effective in the short-term management (up to 120 days) of bruxism.

CAD/CAM lithium disilicate ceramic crowns: Effect of occlusal thickness on fracture resistance and fractographic analysis

This study uses fracture tests and fractographical analysis to compare computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate molar crowns with the previous occlusal thickness recommendation of 1.5-mm, the new recommendation of 1.0-mm, and a less invasive thickness of 0.8-mm. After fatigue application, fracture tests and fractographic analysis were conducted. The fracture resistance of CAD/CAM lithium disilicate molar crowns was different depending on the occlusal thickness of the restoration, and decreased with lower the thickness. However, the fracture resistance of crowns of all three thicknesses exceeded the reported maximum bite force in the first molar region after the fatigue process, and can be considered acceptable for use in the clinic.

The effect of anterior repositioning splint therapy on maximum bite forces in patients with disc interference disorders

OBJECTIVE

To evaluate the effect of anterior repositioning splint (ARS) on maximum bite force (MBF) values in patients with disc interference disorders (DID).

MATERIAL AND METHODS

Twenty-two patients with disc interference disorders and 22 healthy subjects participated in to study. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I have been used to diagnose DID patients. All patients received ARS therapy for 6 weeks. The MBF measurement was performed with Flexi-Force piezo-resistive sensors for both healthy subjects and patients before and after ARS therapy.

RESULTS

A significant difference was recorded by the increase of the mean MBF values after the use of the ARS in the patient with disc derangements (p < .05).

CONCLUSIONS

APS therapy is efficient for eliminating pain and increasing MBF of the patients with DID. In addition, the use of FlexiForce sensors may be a practical solution to assess the bite force in the clinical setting.

The Reliability of a New Device for Measuring the Maximum Bite Force

Objective. To test the inter- and intraexaminer reliability of a recently developed instrument for measuring the maximum bite force (MBF). Material and Methods. Sixty patients who were clinically confirmed as having Oral Submucous Fibrosis (OSMF) and 60 healthy controls were included in this study. For each subject, age, gender, weight, height, and body mass index (BMI) were recorded. The maximum bite force was recorded in alternate order with a bite force sensor (D1) and an occlusal force meter (D2). Bite force was measured in the first molar region. Pearson’s correlation coefficient and kappa statistic were applied to assess the reliability between D1 and D2 in the assessment of maximum bite force. The independent $t$ -test was performed to find the statistical significance between the two study groups. The paired $t$ -test was applied to find out the difference between the right and left disease in groups of two devices separately. The one-way analysis of covariance (ANOVA) was performed to find the significant difference between grades of OSMF. Results. The results of the kappa values were $0.8531\pm 0.0724$ and $0.7336\pm 0.0737$ for interdevice reliability in OSMF patients in right and left sides. Similar findings were obtained in right and left sides of healthy individuals ( $0.7549\pm 0.0816$ and $0.9440\pm 0.0806$ ) and in the total sample ( $0.8132\pm 0.0544$ and $0.8303\pm 0.0538$ ). Pearson’s correlation coefficient between two devices revealed a high and significant positive correlation between D1 and D2 separately and in the whole sample. Conclusion. The observations of the present study suggest that the bite force sensor can be used as a reliable device for measuring bite force.

Fracture resistance of maxillary premolars restored with different endocrown designs and materials after artificial ageing

PURPOSE

To evaluate the effect of three different designs and two monolithic ceramic materials on the durability and fracture resistance of endocrowns on maxillary first premolars, in comparison to post-and-core crowns.

METHODS

Fifty-six maxillary premolars were endodontically treated and shortened to a level of 2 mm from the cervical line, and randomly categorized into six endocrown groups and post-and-core crown control group (n=8); E1; endocrowns with flat occlusal table (without ferrule), E2; endocrowns with 1.5 mm circumferential ferrule, E3; endocrowns with 1.5 mm buccal ferrule preparation. Two materials were used for endocrowns: zirconia (4YSZ; Z), and lithium disilicate (L). The control group was restored with zirconia posts, and lithium disilicate crowns. All restorations were bonded using Panavia V5 and its respective primers and underwent thermo-mechanical fatigue with a 10 kg dynamic load for 1,200,000 cycles and thermocycling between 5 and 55 °C. Thereafter all survived specimens were loaded to fracture. The results were statistically analyzed using ANOVA and T-Test.

RESULTS

None of the specimens showed any signs of debonding or fracture caused by the fatigue test. The PC control group showed no statistically significant difference in comparison to groups ZE1, ZE2 and LE2 ( p > 0.05 ). However, it was significantly different from groups LE1, LE3, and ZE3 ( p ≤ 0.05 ).

CONCLUSIONS

Preparation designs and materials affected the fracture resistance of endocrowns. The results showed a superiority of the post-and-core crowns,zirconia/lithium disilicate endocrowns with 1.5 mm circumferential ferrule, and zirconia endocrowns with the flat occlusal table.

Periodontal Clinical Parameters as a Predictor of Bite Force: A Cross-Sectional Study

OBJECTIVE

To investigate the correlation of periodontal parameters and bite force in different stages of periodontitis after phase I periodontal therapy.

METHODS

Periodontal clinical parameters such as mobility, attachment loss, gingival recession, and percentage of bone remaining were recorded at the mandibular first molar region after phase I therapy in subjects categorized according to the stage of periodontitis. Corresponding bite force was recorded at the first mandibular molar region using a bite force device after phase I therapy. ANOVA test was used to assess the significant difference among different groups. Pearson correlation coefficient was used to assess the correlation between measured variables.

RESULTS

The ANOVA test represents that there is no statistical significant difference between the bite force in stage I, stage II, and stage III type of periodontitis. A strong positive correlation was found (r = 0.537) between bite force and percentage of remaining alveolar bone support whereas negative correlation was observed in measured parameters such as mobility (r = -0.0181), attachment loss (r = -0.608), and gingival recession (r = -0.435).

CONCLUSION

Among all periodontal clinical parameters, the percentage of remaining alveolar bone is the strong predictor of bite force and mobility; attachment loss and gingival recession cannot predict the bite force in the first molar region. Bite force is variable in different stages of periodontitis.

Application Solid Laser-Sintered or Machined Ti6Al4V Alloy in Manufacturing of Dental Implants and Dental Prosthetic Restorations According to Dentistry 4.0 Concept

This paper presents a comparison of the impact of milling technology in the computer numerically controlled (CNC) machining centre and selective laser sintering (SLS) and on the structure and properties of solid Ti6Al4V alloy. It has been shown that even small changes in technological conditions in the SLS manufacturing variant significantly affect changes from two to nearly two and a half times in tensile and bending strengths. Both the tensile and bending strength obtained in the most favourable manufacturing variant by the SLS method is over 25% higher than in the case of cast materials subsequently processed by milling. Plug-and-play SLS conditions provide about 60% of the possibilities. Structural, tribological and electrochemical tests were carried out. In vitro biological tests using osteoblasts confirm the good tendency for the proliferation of live cells on the substrate manufactured under the most favourable SLS conditions. The use of SLS additive technology for the manufacturing of dental implants and abutments made of Ti6Al4V alloy in combination with the digitisation of dental diagnostics and computer-aided design and manufacture of computer-aided design/manufacturing (CAD/CAM) following the idea of Dentistry 4.0 is the best choice of technology for manufacturing of prosthetic and implant devices used in dentistry.

Finite Element Stress Analysis of Applied Forces to Implants and Supporting Tissues Using the "All-on-Four" Concept with Different Occlusal Schemes

PURPOSE

The aim of this study was to evaluate stress distributions on implants and alveolar bone due to occlusal load produced during chewing by prostheses prepared according to the All-on-Four concept with different occlusal schemes using a finite element analysis method.

MATERIALS AND METHODS

On standard jaw models, teeth were set in accordance with the basic standards of canine-guided occlusion, group function occlusion, bilateral balanced occlusion (BBO), lingualized occlusion, and monoplane occlusion schemes. Three-dimensional (3D) images of these models were obtained using a surface scanner. Implants, superstructures, the maxilla, and mandible were modeled in the All-on-Four concept with 3D modeling software. Forces were defined on contacts formed in maximum intercuspation, lateral, and protrusive movement position for all 5 occlusion types. Stress outputs were recorded as maximum and minimum principal stresses (P_max , P_min ) and von Mises stress values for the implants.

RESULTS

The highest P_max value for the maxilla was observed in cortical bone in the group function occlusion during lateral movement (15.56 MPa). For the mandible, the highest P_max value was observed on the cortical bone in maximum intercuspation of lingualized occlusion (72.75 MPa). The highest P_min value for the maxilla was observed during the lateral movement in group function and for the mandible in BBO (-29.23 and -86.31 MPa, respectively). The lowest stress values were observed with canine-guided occlusion in all related conditions and on all structures.

CONCLUSIONS

With the limitations of this simulation study, considering stresses on alveolar bone and implants in All-on-Four applications, the use of canine-guided occlusion may be suggested.

Fracture behaviors of monolithic lithium disilicate ceramic crowns with different thicknesses

The present in vitro study assessed the fracture resistance of monolithic ceramic crowns, made from two lithium disilicate glass ceramics with different thicknesses.