Occlusal Bite Force Research Articles

Comparison of Postorthodontic Occlusal Force Distributions between Nonextraction and Extraction Treatment Approaches of Premolars for Orthodontic Treatment by Using T-Scan III System.

To compare bite force distributions in corresponding mouth regions between postorthodontic patients who underwent nonextraction and extraction approaches using the T-Scan III system (Tekscan, Inc, Massachusetts, United States). Thirty-six postorthodontic patients were divided into two groups: (1) 18 subjects with the nonextraction treatment and (2) 18 subjects with the extraction of four first-premolar treatments. The measurements were performed using the T-Scan to collect the occlusal bite force at the maximal intercuspal position to generate the bite force in the anterior region (incisors and canines) and posterior region (premolars and molars), the bite force in individual teeth, and the anteroposterior bite force ratio (A-P ratio). The mean bite force in each region, individual teeth, and the A-P ratio were compared between the two groups by the Mann-Whitney's U-tests. Within-group comparisons of the mean bite force in each region were performed using Wilcoxon's signed rank tests. The bite force in anterior and posterior regions, and the A-P ratio of the nonextraction group show no significant difference compared with the extraction group (p > 0.05). For individual teeth (central incisors, lateral incisors, canines, second premolars, first molars, and second molars), each tooth exhibited nonsignificantly different bite forces (p > 0.05) except for the second molars. The second molars in the nonextraction group had significantly less bite force than in the extraction group (p = 0.001). The comparison of occlusal bite force between the right and left sides showed that in the nonextraction group, the right side had significantly greater force (p < 0.05). In the extraction group, there was no significant difference between the sides (p > 0.05). Both nonextraction and extraction orthodontic treated patients exhibited the similar bite force distribution patterns in regions and individual teeth except for the higher occlusal force on the second molars in the extractions compared with the nonextractions.

Estimation of Maximum Occlusal Bite Force of School-going Children in Different Dentition: A Cross-sectional Study.

Bite force is an important indicator of the clinical state of mastication and its efficiency. Bite force measurement using a gnathodynamometer is a reliable method to assess the biomechanical properties of the masticatory system. It varies with different geographic populations and physiological and environmental factors. To estimate the maximum occlusal bite force (MOBF) in school-going children of Hyderabad city at different dentition periods and to correlate with different variables. A total of 392 school-going children in the age range of 3-13 years were selected following selection criteria (214 males and 178 females). They were divided on the basis of the dentition period. Demographic details along with general physical parameters such as height, weight, and maximum mouth opening (MMO) were recorded in a predesigned proforma. Maximum bite force was measured using a digital bite force instrument. Maximum occlusal bite force (MOBF) was 18.04 N in primary dentition of age 3-5 years, 47.64 N in mixed dentition of age 6-11, and 108.39 N in permanent dentition of age 12-13 years. The magnitude of bite force was observed to be directly proportional to age, height, weight, and dentition period. Males had greater bite force than females in all three dentitions. However, the difference was significant only in mixed dentition (p < 0.05). Of all the dentition bite force was significantly higher in permanent dentition.Bite force showed an inverse relation with body mass index (BMI) in primary and mixed dentition but a positive correlation was seen with permanent dentition. The mean MMO in males was slightly higher when compared to females. It increased with an increase in the dentition stage. Bite force is multifactorial. It has a significant correlation with physiologic and morphologic factors that influence the values of bite force. Mutt NH, Mallela George MK, Nallanchakrava S, et al. Estimation of Maximum Occlusal Bite Force of School-going Children in Different Dentition: A Cross-sectional Study. Int J Clin Pediatr Dent 2023;16(6):804-809.

Biomechanical analysis and comparison between ‘Zeta’ miniplate design and conventional miniplate system for fixation of fracture segments in transition zone of parasymphysis body region of mandible – an in vitro study

The parasymphysis area of the mandible is highly dynamic because it is subjected to both occlusal and muscular forces. As a result, the fractures in this transition zone have a special pattern, posing a challenge for surgeons whether to use one miniplate versus two miniplates, as per Champy's recommendations. The commonest complication resulting to treat this area is mental nerve paraesthesia due to the dissection and stretching of the nerve. Hence, an in vitro research study of a newly designed ‘Zeta’ miniplate is performed, to evaluate the biomechanical behaviour using finite element (FE) analysis and biomechanical analysis along with a comparison study with the conventional miniplate configurations. The results showed that the Zeta miniplate produces the lowest stresses 17.511 MPa and the least total structural deformation of 0.0011 mm after applying the maximum occlusal bite force. On application of torsional load, total structural deformation was 0.0004 mm and von Mises (VM) stress value was 0.24 MPa which was lowest when compared with the two miniplate system. Hence, the newly developed Zeta miniplate is superior in terms of stability. Another benefit of its design is that it helps in preventing mental nerve paraesthesia and tooth root damage while fixing and stabilising the fractured bony segments.

Validation and Analysis of an Integrated Device for Recording Bite Force and Masseter Muscle Activity in Dentate Participants: An Observational Study

Introduction: The success of any prosthetic rehabilitation depends on acceptable occlusion and muscle coordination. Occlusal therapy should be an integral part of restorative and prosthetic treatment. A thorough diagnosis of bite force and muscle activity is required to ensure the patient’s masticatory function and comfort. The current system of digitisation lacks devices for the simultaneous evaluation of muscle activity and occlusal bite force, representing a significant limitation in understanding and managing restorative and rehabilitation therapy. Aim: To assess the efficacy of an ingeniously designed integrated device that records occlusal bite force and muscle activity. Materials and Methods: An observational study was conducted among 112 healthy volunteers in the Department of Prosthodontics at Sri Ramachandra Dental College and Hospital, Chennai, Tamil Nadu, India, for a period of one month and 45 days, from February 5, 2024 to March 20, 2024. The study aimed to validate the efficacy of a device designed to record bite force and muscle action potential simultaneously. The device consists of two key components: a square Forcesensitive Resistor (FSR) that records changes in resistance in response to applied force and a MyoWare 2.0 muscle sensor with Arduino (Advancer Technologies) for measuring the electrical activity of muscles. Study participants, aged between 21 and 35 years, were seated in an upright position. Muscle activity was recorded with surface electrodes placed on the masseter region, following Surface Electromyography for the Non Invasive Assessment of Muscles (SENIAM) guidelines, while a ground electrode was placed on the neck. Maximum Bite Force (MBF) was measured by placing intraoral pressure sensors, with recordings taken in maximum intercuspation three times, spaced one minute apart for each recording. Both muscle activity and bite force were recorded simultaneously. The Pearson’s correlation coefficient was used to evaluate the correlation between bite forces and muscle action potential with standard average values. Results: The results revealed a strong positive correlation between the masseter muscle activity action potential and the bite force values of the right molar (r=0.964, p&lt;0.001), left molar (r=0.980, p&lt;0.001) and incisor (r=0.550, p=0.002). Conclusion: The device synergistically records muscle activation patterns and bite force distribution, displaying the values in an integrated digital interface. The results of the study reveal that this device can serve as a diagnostic tool in prosthodontic treatment planning.

Evaluation of occlusal bite force distribution by T-Scan in orthodontic patients with different occlusal characteristics: a cross sectional-observational study

BackgroundThe aim of orthodontic treatment, apart from esthetic and functional corrections, is uniform force distribution. Hence Occlusal analysis using a T scan gives scope for a precisely targeted treatment plan. The T-scan evaluation of occlusal force, time, and location of contacts from initial occlusal contact to maximum intercuspation enables the orthodontist to sequentially balance the occlusal forces on the right and left sides through specific treatment plan options.ObjectiveThe current study aimed to determine the force distribution in the different individuals by using a T-Scan as well as the net discrepancies of forces generated at a maximum intercuspation position in the first molar region between the left and right sides of the mouth.MethodsThis is a descriptive-correlational study that was carried out in Ras Al Khaimah College of Dental Sciences clinics and Ajman University clinics from January 2020 to September 2022 by using the convenience sampling technique. The T-scan III Novus was employed in this investigation to record multi-bite scans for several patients. T-scan was utilised to examine various malocclusions.ResultsThe present study consisted of 158 participants. Analysis of Variance (ANOVA) showed that there is a statistically significant difference in the percentage of force between the three types of malocclusions (I, II, and III) on the right molar side (B-16 and B-46) (p < 0.05). Moreover, the overall discrepancy showed a statistically significant difference in the three types of malocclusion classifications (p < 0.05). On the other hand, there was no statistically significant difference in the percentage of force between B-26 and B-36 (p > 0.05). Post hoc analysis showed a statistically significant difference in the percentage of force between malocclusion classes I and III on the right molar, with a mean difference of 4.11190 (p < 0.05). Similarly, there was a statistically significant difference in B-46 between Malocclusion Classes I and II, 4.01806 (p < 0.05). Additionally, post hoc analysis showed a statistically significant difference between malocclusion classes I and III, with a mean difference of -4.79841 (p < 0.05) on the right molar.ConclusionThe T-Scan is a useful tool for assessing occlusal discrepancies and can be helpful during treatment planning and follow-up, especially for orthognathic surgery patients. A T-scan could be used in orthodontic therapy in a simple and efficient way. Also, it turned out to be a useful tool for diagnosing problems and gave us new information about how therapies work. In this study, T-Scan showed that it can measure occlusal forces in timing in an objective, accurate, and repeated manner. The current study found that T-Scan was better able to report the difference in the percentage of force on the right molar side than on the left side.

An In Vivo Study Using T-scan III Occlusal Analysis System: Does the Extraction Pattern Affect the Final Occlusion in Orthodontics?

The assessment of an orthodontic patient's occlusion throughout the treatment and after debonding permits the orthodontist to improve functional occlusion through interventional tooth movements, thus rendering the overall treatmentmore efficient in terms of stability and masticatory efficiency. This study aimed to evaluate the effect of four first premolarextractions during orthodontic treatment on the distribution of bite force using the T-scan III system (Tekscan Inc., Boston, MA). We aim to evaluate the effect of four first premolarextractions during orthodontic treatment on bite force distribution. Ten patients (mean age: 16 ± 2.72 years), who would be treated orthodontically with four first premolar extractions to treat their teeth crowding, were selected for this study. The T-scan III system was utilized to measure the occlusal bite force of the patients before and after treatment, and the findings were compared. There was a non-statistically significant decrease in the occlusal bite force's mean in the arch's anterior segment from 24.45% (± 8.50%) to 14.25% (± 12.93%) after the orthodontic treatment. A non-statistically significant increase in the occlusal bite force in the posterior right segment of the arch from 37.64% (± 18.13%) to 41.65% (± 11.52%) was found after the treatment. The occlusal bite force in the posterior left segment of the arch increased insignificantly from 30.53% (± 20.00%) to 43.95% (± 13.22%). There was an even distribution of bite force on both sides of the arch by the end of the treatment. Orthodontic treatment helps to achieve a functional occlusal balance by assisting in the uniform distribution of biting force on both sides of the arch. There was no statistically significant change in the distribution of bite force recordings collected before and after orthodontic treatment, indicating that the removal of the four first premolar teeth does notimpact the functional aspect of occlusion. The T-scan III system serves as an essential guide during orthodontic treatment to monitor occlusal changes.

Comparative study between patient specific titanium plates versus conventional miniplates for treatment of mandibular fractures: Randomized clinical trial

The aim of the study was to evaluate and assess the clinical stability and efficacy of three-dimensional patient-specific computer-guided titanium plates versus conventional mini plates when used for the treatment of mandibular fractures. Patients with isolated mandibular body fractures were assigned randomly into two equal groups. Group I was treated with patient-specific 3D titanium plates and Group II was treated with conventional mini plates. Outcome measurements included patient satisfaction, pain, occlusion, occlusal bite force and fracture gap distance. All parameters were evaluated at one-week and three-month intervals. The operating time was measured during the surgery. A total of 20 patients were included in the study. Group I (n=10) showed higher values of patient satisfaction and lower pain values than Group II (n=10) at both follow-up intervals. The degree of occlusal derangement showed no statistically significant difference between both groups at one week postoperatively, while both groups showed normal occlusion after 3 months. Occlusal bite forces in Group I were significantly higher than Group II at both follow up intervals. The fracture gap distance was statistically insignificant between both groups at both follow up intervals. The operating time was significantly lower for Group I. Within the limitations of the study, it seems that in the treatment of mandibular body fractures patient-specific plates are preferred over conventional mini plates as they provide more stability, higher biting forces and shorter operating time with highly acceptable outcomes and promising results.

Bite force of children and adolescents: a systematic review and meta-analysis.

This systematic review aimed to assess bite force measurements in children and adolescents and to study the various devices that measure Maximum Voluntary Bite Force (MVBF). This systematic review included observational studies and experimental studies in children and adolescents (upto 19 years of age) which evaluated MVBF using a bite force measuring device. Studies on participants with systemic conditions were excluded. Databases such as PubMed, Embase, LILACS, and the Cochrane library were searched until September 2022, for which screening and quality assessment were performed. Newcastle-Ottawa, modified Newcastle-Ottawa and ROBINS-I tools were used to assess the Risk-of-bias. All observational studies reporting overall bite force values of participants were included for meta-analyses. A total of 8864 participants (3491 males and 3623 females) were included from 61 studies. Meta-analyses were conducted to evaluate mean average bite force value for each included dentition using R software v2.4-0. Estimation was done to derive an average BF value for variables such as age (dentition), gender, side, site, device and ethnicity. MVBF values were reported as mean average in the form of MLN with 95% CI (Confidence Interval). Using a random-effects model, 29 forest plots were generated. I2 values varied between 90% and 100%. Bite force ranged from 246.22 N (220.47; 274.98) to 311.72 N (255.99; 379.59) and 489.35 N (399.86; 598.87) in primary, mixed, and permanent dentitions, respectively. Six different sites for recording bite force and 11 different types of devices were reported with portable occlusal bite force gauge being the most common device. Outcomes of this review provide useful baseline reference values of bite force for clinicians and researchers.

Temporomandibular Joint Disorders among Implant Patients in Relation to Bite Force

Background: The installation of dental implants may impair the temporomandibular joint’s ability to operate by altering bite force. Aim: The aim of this study was to compare dental implant patients with partially and fully dentate patients in terms of temporomandibular joint issues related to maximal bite force measurement. Materials and Methods: Ninety patients with dental implants aged 50–60 years old were compared to 90 with partial and 90 with complete dentition patients who were age and gender matched. The incidence and severity of temporomandibular joint problems among patients were assessed using Helkimo anamnestic and clinical dysfunction indices. By using a biting force sensor, maximum occlusal bite force was measured in accordance with the manufacturer’s instructions as reported at a US-based corporation. Statistical analysis of data was performed using the Statistical Package for the Social Sciences (SPSS) software program, version 22.0 (SPSS, Chicago, Illinois). Results: According to the data, patients in the fully dentate group had larger percentages of Helkimo anamnestic symptom-free and clinically no dysfunction than those patients in implant and partially edentulous groups. Patients in the partially edentulous group were more likely to have Helkimo anamnestic mild and severe symptoms, as well as clinical mild, moderate, and severe dysfunction than patients in the other two groups. These data, however, did not show a statistically significant association. Data analysis revealed that maximum bite force measurements were significantly different between groups for all Helkimo anamnestic and clinical indices. Conclusion: Following oral implant therapy, the function of the temporomandibular joint was affected. In addition, bite force measures decreased as temporomandibular disorder symptoms became more severe.

Review of several clinical factors that affect the occlusal bite forces

Occlusal bite forces are the most critical consideration factor in treatment planning. Measurement methods ofocclusal bite forces were developed in a century, and affected factors are studied in many experiments. Gender, age, shapes of facial morphology, teeth position, periodontal states, etc., are revealed affective aspects of theocclusal bite forces. The dental clinician should make a treatment plan by considering occlusal bite forces and would predict the patient's prognosis. In clinical procedures, several specific factors that include endodontic treatment, implant treatment, and com-plete denture prosthesis cause severe results after treatments. If clinicians do not consider these factors before the treatment procedures, extraction of the tooth, implant, and dismission of the complete denture are struggled by patients. These factors (endodontic treatment, Implant, complete denture prosthesis) cause the changes of occlusal bite forces, and then consideration of these changes makes a great result of treatment. The purpose of this study was to summarize the parts that clinicians can refer to based on reviewing studies on complex factors that affect occlusal bite force.

Evaluación de la fuerza de mordida molar en dentición temporal cariada y no cariada en niños de 4 a 6 años

Objetive: The aim of the study was to evaluate the maximum molar bite force in children aged 4 to 6 years with and without dental caries. Material and Methods: This cross sectional study was carried out from May 2018 to December 2018. A total of 288 children aged between 4 to 6 years were randomly selected from six different primary schools in Chennai city, India and divided into two groups of 144 children each, based on the presence and absence of caries: Group A children with non-carious dentition and Group B children with carious dentition. Bite force measurement was performed using standardized custom made occlusal force gauge. Statistical analysis used: Data were expressed as the mean ± SD. Student’s t‑test (two tailed, independent) and ANOVA were used to find the significance of study parameters between the groups. Results: Occlusal bite force of non-carious dentition (367.94 ±33.71N) was higher than the carious dentition (326.73±27.83N) and it was statistically significant (p≤0.01). Overall occlusal bite force of boys (350.44±35.84N) was significantly higher than that of girls (344.22±38.25N). Flush terminal plane molar relationship showed higher occlusal bite force (380.54±27.36N) followed by mesial step (350.82±22.25N) and distal step (310.63±20.82N) molar relationship. Conclusion: Non-carious dentition showed significantly higher bite force than carious dentition in children 4 to 6 years of age. Boys had higher bite force than the girls and flush terminal plane molar relationship showed higher bite force than mesial and distal step molar relationship.

Does Orthodontics Extractions Negatively Affect The Occlusal Bite Force Of An Individual - A Quasi-Experimental Study.

Orthodontics is said to be that branch of dentistry which takes into consideration the facial growth, dentition development as well as occlusion. It is also concerned with the prevention as well as the rectification of the occlusal anomalies. The aim of this study was to determine the occlusal bite force (OBF) changes during fixed orthodontic treatment up to a period of 9 month in Class I patients treated with extraction and non-extraction treatment protocol. It was a Quasi-experimental study conducted from 13th March 2018 to 20th March 2019 in the orthodontic department on 90 subjects which were divided into a treatment group {extraction (30), non-extraction (30)} and controls (n=30). Bite force was measured with an OBF gauge at 6 different intervals before starting the treatment to the ninth month of the treatment. The changes in OBF were assessed using r-ANOVA test. Post-hoc Bonferroni was used for multiple comparisons in bite force levels at different treatment stages. The mean difference in OBF between treatment groups was evaluated by independent t-test. Significance for all tests was predetermined at p value of ≤0.05. The mean OBF significantly increased in both the extraction and non-extraction treatment groups (p<0.001) in comparison to the controls. The mean change in OBF was comparatively greater in the non-extraction group as opposed to the extraction group, but the difference was not statistically significant (p=0.468). Orthodontic treatment has a positive effect with a gradual increase in the OBF values in subjects treated with extraction and non-extraction fixed mechano-therapy. This indicates that well-aligned arches can have an impact on the functional occlusion, hence, enhancing the bite force levels.

Comparison of settling of occlusion in modified and full coverage thermoplastic retainers using T-scan

Objectives: The main intent of the study was to evaluate and compare the occlusal bite forces after settling between conventional and modified thermoplastic retainer groups using T-Scan. Material and Methods: This study comprised a total of 20 patients, who approached the retention phase after completion of fixed orthodontic therapy. After debonding (T0), occlusal analysis using the T-Scan system was done at centric occlusion. Group I (control) – 10 patients received the conventional thermoplastic retainer and Group II (experimental) – 10 patients received the modified thermoplastic retainer. Patients were instructed to wear the retainer continuously for 6 months except while eating and brushing. T-scan analysis after 6 months (T6) was done to evaluate the changes in occlusal bite forces. The obtained data were evaluated using STATA/IC software version 16.1 at a predetermined probability value of 0.05 which was considered significant. Results: The result obtained from this study was suggestive of significant improvement in bite force levels at centric occlusion in the modified thermoplastic group compared with the conventional group. Comparing the right (P &lt; 0.17) and left (P &lt; 0.01) posterior region, there was significant increase on the left side. A significant increase at maximum centric occlusion (P &lt; 0.01) was seen in the region of the first molars. The anterior region did not show any improvement (P &lt; 0.62) after 6 months of retention. Conclusion: Partial coverage of thermoplastic retainer significantly improves the occlusal contacts and force levels. The maximum change was seen in the posterior region and the minimum change in the anterior region at centric occlusion.

Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9-12 Years: A T-scan Analysis.

Aim and objectiveCompare and evaluate the muscle activity and the occlusal force between the mixed dentition boys and girls of 9–12 years.Materials and methodsThe study included 15 boys and 15 girls. The occlusal force and activity of the masseter and temporalis muscle were measured with a T-scan device using a sensor, a module to transmit the signals to a computer and the complete data of the bite force and muscle activity with the EMG recordings and data were collected and evaluated.ResultsRelative occlusal force in the primary and permanent molars between the boys and girls showed no significant difference on the left side compared to the right. The electromyography values of masseter and temporalis in boys and girls showed a significant difference in which (TAR and MMR), (TAR and MML), (TAL and MMR), and (TAL and MML) are significant. The overall paired sample statistics showed higher muscle activity in masseter.ConclusionT-scan analysis has proved to be a dependable method for the evaluation of occlusal bite force with the muscle activity interpretation using EMG. This study concluded that there is a difference in the occlusal pattern and muscle activity in the mixed dentition that showed the maximum force was on the permanent molars and the symmetry of EMGs activity in children was on the right masseter comparatively with higher bite values in boys compared to girls.Clinical significanceT-scan is a computerized analysis system that helps in the proper assessment of the patient's occlusion and assists in the proper treatment planning and diagnosis accurately without much effort.How to cite this articlePrabahar T, Gupta N, Chowdhary NR, et al. Comparative Evaluation of Occlusal Bite Force in Relation to the Muscle Activity in the Mixed Dentition Children of Age Group 9–12 Years: A T-scan Analysis. Int J Clin Pediatr Dent 2021;14(S-1):S29–S34.

The Relationship between Dentofacial Vertical Pattern and Bite Force Distribution among Children in Late Mixed Dentition

Background: Digital bite measurement systems such as the T-Scan III allow for the computerized measurement of occlusal force distribution. This study aimed to establish the relationship between dentofacial vertical pattern and bite force distribution among children in late mixed dentition. Materials and Methods: In total, 86 children (45 male, 41 female) aged between 9 and 11 years with short (n = 28), medium (n = 28), and long (n = 30) facial heights were included in this study. The height, weight, age, and gender were recorded. Occlusal bite force distribution and time of occlusal cycle were recorded using a T-Scan III device (Tekscan Corp. Boston, MA, USA). The bite force distribution was compared among facial types using a One-Way ANOVA and post hoc test, a linear regression model with time of occlusion as dependent variable was developed. Results: No significant differences were observed in occlusion time between genders. Children with long facial height had a significantly lower anterior bite force distribution (p &lt; 0.05) and significantly higher posterior bite force distribution (p &lt; 0.05) than those with average or short facial height. Age, gender, height, and weight had no significant association with time of the occlusal cycle. Conclusion: Children with an increased vertical facial height have a more posterior distribution of force than children with average or short facial heights in the late mixed dentition.

Patient-Centered Treatment Outcomes with Full-Arch PEEK Rehabilitation Supported on Four Immediate or Conventionally Loaded Implants. A Randomized Clinical Trial.

This study aims to assess the treatment outcomes (functional and subjective) of full-arch fixed hybrid rehabilitations made of PEEK (poly-ether-ether-ketone) with milled crowns of nano-filled composite (NFC) supported on four to six implants. In this randomized clinical trial, 34 edentate patients in the upper and/or the lower jaws were treated with the fixed hybrid dentures. In 16 patients (47.1% of the sample), the implants were loaded immediately (IL) by means of a provisional fixed rehabilitation made of PMMA (polymethylmethacrylate) screwed on Multi-Unit (MU) abutments connected after emplacement of the implant; however, in the counterparts (n = 18) these MU abutments were covered by healing caps and were left unloaded during two months (conventional loading protocol—CL), when all patients received a fixed hybrid PEEK-NFC rehabilitation on the upper and/or the lower jaw. Treatment outcomes were assessed 12 months after prostheses delivery. Functional outcomes were calculated according to masticatory performance, estimated by mixing ability tests of two colored chewing gums after ten chewing strokes, by the occlusal force/area recorded by pressure-sensitive sheets, and by electromyography of masseters and temporal muscles at maximum biteforce. The subjective outcomes of the treatment were assessed using both the oral satisfaction scale (visual analog scale) and the Spanish version of the Oral Health Impact Profile (OHIP-20). The findings of the present study showed that treatment with fixed PEEK-NFC hybrid prostheses significantly improved the masticatory performance, bite force, occlusal pattern, quality of life, and satisfaction, with the IL group being those with significantly higher occlusal bite forces and greater satisfaction in comparison with CL group. It should be concluded that PEEK-NFC hybrid prostheses can improve several patient-centered outcomes and that loading protocol significantly affects the patient’s self-rated satisfaction.

Occlusal contact of primary dentition at intercuspal position in children with individual normal occlusion

Objective: To record occlusal contact of primary dentition at maximal intercuspal position in children with individual normal occlusion. Methods: A total of 57 children were recruited from patients of the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology. Inclusion criteria were that the subjects were 3-5 years old with no visually detectable caries or pupal and periapical diseases, had complete primary dentition, had individual normal occlusion, had normal function of craniofacial system, were medically healthy, could cooperate with sampling and had obtained written informed consent from the parents or guardians. Finally, forty-seven children aged 3 to 5 years old were enrolled, including 24 males and 23 females. The age, height and weight of all subjects were (4.1±0.7) years old (ranging 3.0-5.8 years old), (103.7±7.2) cm (ranging 90-120 cm) and (17.1±2.5) kg (ranging 12.5-22.5 kg), respectively. Occlusal abilities such as occlusal contact area, average bite pressure, maximum bite pressure, maximum bite force and occlusal balance were measured with Dental Prescale Ⅱ system. Results: Maximum bite force and occlusal contact area at intercuspal position in children with primary dentition were (567.40±223.84) N (ranging 226.7-1 154.6 N) and (18.56±6.54) mm2 (ranging 8.4-41.2 mm2), respectively. There was a significantly strong correlation between maximum bite force and occlusal contact area (r=0.954, P<0.01). Height and weight of children were also positively correlated with their maximum bite force (r=0.397, P=0.022 and r=0.453, P=0.008, respectively). Maximum occlusal bite force and contact occlusal area of boys [(651.80±224.34) N and (20.77±6.97) mm2] were significantly higher and larger than those of girls [(479.34±190.45) N and (16.25±5.27) mm2] (P<0.05). Thirty-two of all 47 children had one occlusal contact point with maximum bite pressure, mostly locating within the primary molar region. Bite forces of anterior and posterior teeth of primary dentition were (124.12±56.99) N and (450.11±205.09) N, respectively, about (21.82±11.40)% and (71.80±21.35)% of maximum bite force of the whole primary dentition. All of the occlusal balance points located in posterior teeth regions. Occlusal contacts were observed at both anterior and posterior teeth of primary dentition with individual normal occlusion. Conclusions: There was a great variation of maximum bite forces of primary dentitions at intercuspal position of children with individual normal occlusion. Maximum bite force of primary dentition was significantly correlated with occlusal contact area, height and weight of children. Occlusal contact points with maximum bite pressure and occlusal bite balance points of primary dentitions mostly located in primary molar regions.

Bite force changes after surgical correction of mandibular prognathism in subjects with increased vertical dimension : Aprospective clinical trial.

Occlusal bite force (OBF) is the most important parameter in assessing biting efficiency. The aim of this study was to record OBF changes after surgical correction of high angle maxillary/mandibular (Max/Mand) classIII patients and to compare these with that recorded in classIII patients with average Max/Mand angle. Initially included were 42patients with severe classIII skeletal malocclusion who were scheduled for orthodontic surgery: group1-22patients with increased vertical relationship scheduled for bimaxillary surgery; group2-20patients with average vertical relationship scheduled for mandibular setback only. OBF measurements before surgery (T0), at debonding (T1) and at least 3months after debonding (T2) were recorded using aportable occlusal force gauge. The following were also measured: maximum OBF (MOBF) achieved by the subject on each side, averaged OBF on each side (AOBF) and maximum OBF at the incisal region (MIOBF). At T2, only 33patients (group 1: 17 and group 2: 16) were included in the analysis due to loss to follow-up. MOBF increased significantly in group1, while no significant changes were detected in group2. MIOBF increased after surgical correction in both groups. Significant increase in MIOBF was observed at T1 (P < 0.001) followed by an insignificant decrease during the observation period (3-6months after treatment; P > 0.05). The two groups differed significantly in MOBF at T1 and T2, while no statistically significant differences were detected between the groups for MIOBF changes at the various time intervals (P > 0.05). The number of posterior teeth with occlusal contacts increased in both groups. Relapse was detected in group1 where the number of posterior teeth in contact decreased during the observation period (T1-T2). OBF greatly improved after surgical correction of the vertical morphology. Correction of high angle mandibular prognathism improves oral function in addition to esthetics.

Influence of Occlusal Bite Forces on Teeth with Altered Periodontal Support: A Three-Dimensional Finite Element Stress Analysis.

Background:Masticatory forces generate various degrees of stress and strain in the periodontium of teeth which determine the clinical functions and load-bearing capacity of the teeth. There are few in vitro studies that have analyzed stress generated due to combined forces acting on the teeth. Thus, the objective of the present study was to do a comparative analysis of the influence of various stresses on the periodontal ligament and alveolar bone of maxillary central incisor with normal bone height and reduced bone height under simulated standard masticatory using finite element stress analysis.Methodology:A 3D model of the tooth was obtained with the help of ANSYS software. These models were subjected to various oblique forces, i.e., 100N and 235.9N, applied at 45° angle on the lingual surface of the maxillary central incisor and stress values were recorded in three dimensions. The results from FE analysis were analyzed using 3D Von Mises Criteria.Results:It was observed that in healthy periodontium; it was observed that among the periodontal structure studied, the maximum stress levels were exerted on root followed by cortical bone, cancellous bone, and PDL, irrespective of the force, as compared to the diseased periodontium, in which the bone height was reduced, the maximum stresses were on root followed by cortical bone, PDL, and cancellous bone.Conclusion:The main factor governing the success of any periodontal procedure depends on the height of the remaining bone and the amount of force exerted on to the tooth and the stress generated within the tooth. The finite element method could be of substantial importance in this respect as it can assess the stresses of various occlusal forces on the periodontal ligament, root, cortical bone, and cancellous bone of teeth in a periodontally healthy and diseased state.

Load to failure of high-density polymers for implant-supported fixed, cantilevered prostheses with titanium bases.

To analyze the load to failure of different CAD/CAM high-density polymers (HDPs) and zirconia when titanium (Ti) bases were included in a cantilevered situation. Five specimens were fabricated from five different CAD/CAM polymethyl methacrylate (PMMA) HDPs (Copratemp [CT]; Tempo-CAD [TC]; TD Dental [TD]; M-PM Disc-Pink [MPM]; M-PM Disc-White [MPMW]), and five specimens were prepared from a 3Y-TZP zirconia (FireZr [FZR]) (control). Ti bases (D Master Dental Implants) were cemented onto the specimens (8 mm [thickness] × 7 mm [width] × 30 mm [length]). Each specimen was fixated using a clamp for a cantilever loading distance of 10 mm. The load was applied on the cantilever until failure, and the maximum load to failure values (N) were analyzed by using analysis of variance (GLIMMIX procedure) with a lognormal error distribution in addition to the restricted maximum likelihood estimation method to eliminate the need for equality of variances and Tukey Honest Significant Difference (α = .05). Differences among load-to-failure values of HDPs were not significant (P > .05). However, zirconia had significantly higher load-to-failure values than HDPs (P < .001). The behavior of HDPs and zirconia under loading was different in terms of displacement. HDPs showed weaker but more ductile behavior than zirconia, which is stronger, but more brittle. Tested brands of HDPs performed similarly under loading. Zirconia with a Ti base showed higher strength compared to all tested HDPs with a Ti base. The loads that fractured the specimens with Ti bases were close to the maximum occlusal bite forces recorded in previous clinical studies.