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Table of Contents   
ORIGINAL RESEARCH  
Year : 2020  |  Volume : 31  |  Issue : 5  |  Page : 706-711
Influence of personality traits on the intensity of maximum voluntary bite force in adults


1 Research Scholar, Pacific Dental College, PAHER University, Pacific Hills, Udaipur, Rajasthan, India
2 Department of Pedodontics and Preventive Dentistry, Pacific Dental College, PAHER University, Udaipur, Rajasthan, India
3 Department of Conservative Dentistry and Endodontics, Chettinad Dental College and Research Institute, Kelambakkam, Kanchipuram District, Tamil Nadu, India
4 Department of Conservative Dentistry and Endodontics, Ragas Dental College and Hospital, Uthandi, Tamil Nadu, India

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Date of Submission22-Jun-2019
Date of Decision04-Nov-2019
Date of Acceptance07-Jan-2020
Date of Web Publication08-Jan-2021
 

   Abstract 


Purpose: To determine the Maximum voluntary bite force among patients having different personality traits. Methods: In total, 323 patients were given the big-five inventory (BFI) questionnaire to fill and allotted to the various personality traits. The patients in the Agreeableness (n = 62) and Neuroticism traits (n = 62) were included in the study. They were categorized into groups as Group 1a – Neuroticism male (41 patients) and Group 1b – Neuroticism Female (21 patients) and Group 2a – Agreeableness male (26 patients) and Group 2b – Agreeableness female (36 patients). Highest value of the maximal voluntary bite force (MVBF) was recorded using FlexiForce sensor (B 201) (Tekscan, USA). The statistical data were analyzed by independent t-test (P < 0.05). Results: The mean bite force values for Neuroticism male was 778.66 N, Agreeableness male was 699 N, Neuroticism female was 686.24 N, and for Agreeableness female was 565.47 N. Statistically significant differences in the bite forces between the male and female groups of both the groups with the males showing significantly higher bite force values in both groups was seen. Also, the bite force in Neuroticism male was significantly higher than Agreeableness male and bite force in Neuroticism female was higher than Agreeableness female. Conclusion: In this study, the highest bite force was seen in Neuroticism males. Additionally, this study infers that personality has significant influence on the quantum of bite force. Thus, personality assessment of the patient can assist the clinician in planning the appropriate treatment.

Keywords: Big five inventory questionnaire, bite force, personality traits

How to cite this article:
Khan SI, Rao D, Ramachandran A, Ashok BV. Influence of personality traits on the intensity of maximum voluntary bite force in adults. Indian J Dent Res 2020;31:706-11

How to cite this URL:
Khan SI, Rao D, Ramachandran A, Ashok BV. Influence of personality traits on the intensity of maximum voluntary bite force in adults. Indian J Dent Res [serial online] 2020 [cited 2021 Jan 28];31:706-11. Available from: https://www.ijdr.in/text.asp?2020/31/5/706/306451



   Introduction Top


Personality can be defined as “the dynamic organization of the psychobiological systems that modulate adaptation to changing environments through several personality traits, which are long-lasting patterns of how we perceive, relate to, and think about oneself, other people and the world as a whole”.[1] Thus, every person/patient visiting a dental clinic will have a distinct personality. These personality traits predict psychosocial behavior, psychopathology, physical health, and mortality.[2]

There are many scales to assess personality, out of these, the “Big-Five” framework is one of the most commonly recommended and researched model of personality.[3] It uses 44 short sentences based on the marks of the Big Five. The measured characteristics are E (Extraversion, Energy, Enthusiasm), A (Agreeableness, Altruism, Affection), C (Conscientiousness, Constraint, Control of impulse), N (Neuroticism, Negative affectivity, Nervousness), and O (Openness, Originality, Open Mindedness). This BFI has been translated and validated in different languages.

Psychological factors such as stress, anxiety, and mood disturbances; temperamental traits and emotions and social factors such as workplace satisfaction, marital status, cultural and economic conditions, social behaviors, and expectations may have an effect on the physical health status.[4] It has been found that emotional stress is associated with an increased chewing frequency, as chewing is an autonomic behavior in response to stressful conditions, helping in stress-coping mechanisms.[5]

Maximum voluntary bite force (MVBF) is an indicator of the functional state of the masticatory system and the intensity of maximum bite force results from the combined action of the jaw elevator muscles modified by jaw biomechanics and reflex mechanisms. The amount of bite force generated is one of the key influencers on the wear resistance and the clinical performance of restorations.[6] Hence, it is necessary to find out the different factors which interplay in the process of bite force generation.

Although there is sufficient body of evidence proving that personality traits are essential patient's health care, their role have not been sufficiently explored in dentistry. The primary reason for this could be that, the idea of personality and its traits are novel to most dentists; hence, they are mainly overlooked in dental research and practice, in spite of sufficient body of evidence supporting its validity.

Our literature search revealed that there has been no study done till date, to the best of our knowledge, regarding the influence of personality traits in the quantum of bite force generated in humans; hence, we hypothesize that patients with certain personality traits might have increased bite force which may influence the dental status of the patients.


   Materials and Methods Top


The study was approved by the ethics committee from Ragas Dental College, Chennai (ethical clearance number – 20180730), where the study was carried out. The inclusion criteria were age between 20 and 35 years and the presence of full set of permanent dentition (at least 28 excluding third molars) with a bilateral angle class I molar and canine relationship. Patients having large occlusal restorations, presence of endodontically treated teeth, fixed prostheses, or active periodontal disease were excluded. Also, presence of local or systemic, osseous or neuromuscular disease, presence of spontaneous orofacial pain, temporomandibular joint disorder symptoms, large facial asymmetry, and pregnancy were not considered for the study. All patients were required to give informed consent before starting the study.

Big Five Inventory (BFI) as suggested by John OP and Shrivastava S[7] consists of 44 items measuring five trait dimensions of personality – extraversion (eight items), Agreeableness (nine items), conscientiousness (nine items), Neuroticism (eight items), and openness to experience (nine items) – and uses a five-point Likert scale from 1= “strongly disagree” to 5= “strongly agree.” It is designed in such a way that some of the items were strategically formulated backward to control the consistency of the participants (response bias).

Subjects, in accordance with the inclusion and exclusion criteria, were given the BFI-questionnaire (Appendix 1)[7] to fill and were evaluated accordingly with the help of a psychiatrist and allotted to the various personality traits as per the scores. Out of total 323 patients, the patients falling in to the Agreeableness and Neuroticism traits were included in the study for further investigation. The measurements of bite force were recorded with the subjects seated in an upright, looking forward, in an unsupported natural position - sitting in the dental chair with the head not resting anywhere, in a relaxed position. The recordings were done in a single session for each subject using a portable customized bite recording FlexiForce sensor (B 201) (Tekscan). The data were captured in Newtons (N) and displayed on the computer monitor using FlexiForce ELF system (Economical load and force measurement system, Tekscan). In total, 134 patients belonging to Neuroticism (62) and Agreeableness (62) were included in the study. They were categorized into groups as Group 1a – Neuroticism male (41 patients) and Group 1b - Neuroticism female (21 patients) and Group 2a – Agreeableness male (26 patients) and Group 2b – Agreeableness female (36 patients).

Bite force recordings were done bilaterally in first molar region within few seconds of maximal clenching. Recording of the measurements were repeated three times in intervals of about 1 min between each measurement to avoid fatigue on each side. Highest value of the maximal voluntary bite force (MVBF) was recorded among the six measurements and was statistically analyzed. Statistical analysis was performed using SPSS version 20.0 (SPSS; Chicago, IL, USA). The statistical data among the groups were compared by independent t-test (P < 0.05).


   Results Top


The mean bite force values for Neuroticism male were 778.66 N and for Agreeableness male were 699 N. The mean bite force values for Neuroticism female were 686.24 N and for Agreeableness female were 565.47 N [Table 1]. The statistical analysis of the current study shows that there is a significant difference in the bite forces between the male and female groups of both the Neuroticism and Agreeableness with the males showing significantly higher bite force values in both groups. The results also show that the bite force in Neuroticism male was significantly higher than that of Agreeableness male. Similarly, the bite force in Neuroticism female was significantly higher than that of Agreeableness female.
Table 1: Comparison of bite force between male and female among the two groups of neuroticism and agreeableness

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   Discussion Top


The influence of cerebral cortex and subcortical effects in the generation of rhythmic orofacial activity in mastication has been demonstrated.[8] Hence, the action of chewing is not only mediated by local factors but also effectively controlled by central factors.[5]

The hypothesis of the current study investigating the influence of personality on the behavior of masticatory system is in accordance with previous research which investigated the impact of personality on human physiological systems and claimed that the brains internal architecture is unique to different personalities.[9]

Among the various personality test models, the Big-Five-factor model is a widely accepted hierarchical model of personality. This five-factor model stipulates that the five personality traits are to a greater extent a product of biology than a product of life experiences and thus are relatively stable dispositions.[10]

The Agreeableness trait includes characters like being kind, trustful, magnanimous, expressing sympathy, collaborative, affectionate and not showing aggressiveness, whereas the neuroticism trait includes characters such as nervousness, being stressful, often getting angry, fighting behavior, unhappiness, shyness, being aggressive, hasty, and vulnerable.[3] Out of five BFI personality traits, these two personality traits – Neuroticism and Agreeableness were taken for the study as they mostly exhibit characters opposite to each other.

The results of this study state that there exists a strong correlation between the presence of neuroticism-related traits and high MVBF. This is in accordance with the participants of a previous study who measured high on Neuroticism-related traits reported that they often grind their teeth.[11] This frequent use of the masticatory system could have resulted in its increased strength and in increased MVBF.

It has been stated that Neuroticism characteristic individuals are associated with emotional disability and experience high incidence of binge eating habit.[12] On the contrary, Agreeableness trait individuals are pliable, experience less stress, and are readily willing to follow the guidelines for healthy diets thus showing improved physical and psychological health. The increase in MVBF of Neuroticism patient may be attributed to the frequent chewing during stress episodes and binge eating which could have resulted in hypertrophy of the masseter muscle leading to increased MVBF. Masseter muscle hypertrophy is a condition that manifests itself as enlargement of the masseter muscle and can be unilateral or bilateral.[13]

The above correlation is in accordance with the previous study which states that etiology of masseter muscle hypertrophy is associated to many factors, including emotional stress, chronic bruxism, and masseteric hyperactivity.[14] The role of muscles of mastication especially the thickness of masseter and its paramount role in the intensity of generated bite force has already been established.[15]

Furthermore, the increase in bite force may also be attributed to the strength of the underlying jaw bone, which can be explained by wolf's law which states that bone in a healthy person or animal will remodel to the loads placed on it. If loading on a particular bone increases, the bone becomes thicker and stronger and vice versa. According to this biodynamics, chronically stressful patients with stronger hypertrophic masseter muscle influence the underlying jaw bone to become powerful, contributing to overall increase in MVBF.

Additionally, Neuroticism patients are more commonly associated with GAD (generalized anxiety disorder), which result in hyperactivity of temporalis muscle.[16],[17] Hence hyperactivity of temporalis muscle, a component of masticatory system could also be an important factor for the increase in MVBF.

Also, in our study, males are having higher MVBF when compared with females, this in accordance with many previous studies and is attributed to the fact that males have prominent muscular anatomy and strength when compared to females.[18] The masseter muscle in males have type II muscle fibers with more thickness and cross sectional area than that of females[19] contributing to their increased MVBF. Although best efforts are done to minimize the effect of other influential factors like age, socioeconomic factor, and ethnicity on bite force measurements nevertheless these confounders making an impact in the measured MVBF cannot be completely eliminated which can be considered as one of the limitations of this study.


   Conclusion Top


Within the limitations of the present study, the results clearly states that personality has significant influence on bite force. Thus, it can be stated that persons with certain psychological trait have the indigenous ability to generate higher amount of occlusal forces. From a clinical point of view, assessment of personality traits will be useful in recommending a suitable restorative material or appropriate prosthesis design, thereby overall improving the quality of treatment provided.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

The authors declare that there is no conflict of Interest related to this study.


   Appendix - 1 Top


How I am in general

Here are a number of characteristics that may or may not apply to you. For example, do you agree that you are someone who likes to spend time with others? Please write a number next to each statement to indicate the extent to which you agree or disagree with that statement.



I am someone who…

  1. _____ Is talkative
  2. _____ Tends to find fault with others
  3. _____ Does a thorough job
  4. _____ Is depressed, blue
  5. _____ Is original, comes up with new ideas
  6. _____ Is reserved
  7. _____ Is helpful and unselfish with others
  8. _____ Can be somewhat careless
  9. _____ Is relaxed, handles stress well.
  10. _____ Is curious about many different things
  11. _____ Is full of energy
  12. _____ Starts quarrels with others
  13. _____ Is a reliable worker
  14. _____ Can be tense
  15. _____ Is ingenious, a deep thinker
  16. _____ Generates a lot of enthusiasm
  17. _____ Has a forgiving nature
  18. _____ Tends to be disorganized
  19. _____ Worries a lot
  20. _____ Has an active imagination
  21. _____ Tends to be quiet
  22. _____ Is generally trusting
  23. _____ Tends to be lazy
  24. _____ Is emotionally stable, not easily upset
  25. _____ Is inventive
  26. _____ Has an assertive personality
  27. _____ Can be cold and aloof
  28. _____ Perseveres until the task is finished
  29. _____ Can be moody
  30. _____ Values artistic, aesthetic experiences
  31. _____ Is sometimes shy, inhibited
  32. _____ Is considerate and kind to almost everyone
  33. _____ Does things efficiently
  34. _____ Remains calm in tense situations
  35. _____ Prefers work that is routine
  36. _____ Is outgoing, sociable
  37. _____ Is sometimes rude to others
  38. _____ Makes plans and follows through with them
  39. _____ Gets nervous easily
  40. _____ Likes to reflect, play with ideas
  41. _____ Has few artistic interests
  42. _____ Likes to cooperate with others
  43. _____ Is easily distracted
  44. _____ Is sophisticated in art, music, or literature


SCORING INSTRUCTIONS

To score the BFI, you'll first need to reverse-score all negatively-keyed items:

Extraversion: 6, 21, 31

Agreeableness: 2, 12, 27, 37

Conscientiousness: 8, 18, 23, 43

Neuroticism: 9, 24, 34

Openness: 35, 41

To recode these items, you should subtract your score for all reverse-scored items from 6. For example, if you gave yourself a 5, compute 6 minus 5 and your recoded score is 1. That is, a score of 1 becomes 5, 2 becomes 4, 3 remains 3, 4 becomes 2, and 5 becomes 1.

Next, you will create scale scores by averaging the following items for each B5 domain (where R indicates using the reverse-scored item).

Extraversion: 1, 6R 11, 16, 21R, 26, 31R, 36

Agreeableness: 2R, 7, 12R, 17, 22, 27R, 32, 37R, 42

Conscientiousness: 3, 8R, 13, 18R, 23R, 28, 33, 38, 43R

Neuroticism: 4, 9R, 14, 19, 24R, 29, 34R, 39

Openness: 5, 10, 15, 20, 25, 30, 35R, 40, 41R, 44



 
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Bakke M. Bite force and occlusion. Semin Orthod 2006;12:120-6.  Back to cited text no. 19
    

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Correspondence Address:
Dr. Sulthan I R. Khan
Research Scholar, Pacific Dental College, PAHER University, Pacific Hills, Pratap Nagar Extension, Airport Road, Udaipur, Rajasthan - 313003
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijdr.IJDR_517_19

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    Abstract
   Introduction
    Materials and Me...
   Results
   Discussion
   Conclusion
   Appendix - 1
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