Mouth opening range for Jordanian population and its relation to gender, age, height, and weight

Mirvet Mohammed Hawwa

doi:10.4103/sidj.sidj_3_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 6 | Issue : 1 | Page : 12-15

Mouth opening range for Jordanian population and its relation to gender, age, height, and weight

Mirvet Mohammed Hawwa
Department of Oral and Maxillofacial Surgery, Wadi Al-Seer Comprehensive Medical Center, Jordanian Ministry of Health, Amman, Jordan

Date of Submission	31-Jan-2022
Date of Acceptance	05-Apr-2022
Date of Web Publication	27-Jun-2022

Correspondence Address:
Dr. Mirvet Mohammed Hawwa
Department of Oral and Maxillofacial Surgery, Wadi Al-Seer Comprehensive Medical Center, Jordanian Ministry of Health, Amman 11810
Jordan

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/sidj.sidj_3_22

Abstract

Aim: Maximum mouth opening (MMO) is an important parameter in the assessment of several clinical situations, and its measured value is documented to have gender, age, and anthropometric variation.
Background: This study measures the average value of MMO in a sample of the Jordanian population. MMO might be different for different regions of the world and is important for all dental disciplines. We attempt to find correlations between MMO and body characteristics such as gender, age, body weight, and height.
Materials and Methods: A total of 565 Jordanian patients (191 males and 374 females; aged 3–70 years) were randomly selected for this cross-sectional study. Mouth opening was measured using a calibrated ruler between the incisal edges of the upper and lower central incisors (interincisal length), and weight and height were measured using a medical scale. In addition, age and gender were recorded. Patients were informed of the study and agreed to participate. Statistical differences of MMO between male and female patients in each age group were assessed using the t-test, the correlation between the MMO and body weight and height was assessed using a Pearson correlation coefficient and simple linear regression using the SPSS program.
Results and Conclusions: The mean MMO across the sample was 45 ± 4.78 mm with a range of 36–61 mm. The mean MMO in males was 45.7 ± 5.2 mm, varied from females, which was 44.65 ± 4.4 mm in all age groups with the level of significance of (P = 0.013). No significant relation was found between age and MMO with a P of (>0.05), but a significant correlation was found between MMO and body weight and height with a P of (<0.01).

Keywords: Age, body height, body weight, gender, maximum mouth opening

How to cite this article:
Hawwa MM. Mouth opening range for Jordanian population and its relation to gender, age, height, and weight. Saint Int Dent J 2022;6:12-5

How to cite this URL:
Hawwa MM. Mouth opening range for Jordanian population and its relation to gender, age, height, and weight. Saint Int Dent J [serial online] 2022 [cited 2023 Jun 5];6:12-5. Available from: https://www.sidj.org/text.asp?2022/6/1/12/348383

Introduction

The maximum distance between the incisal edge of the maxillary central incisors and the incisal edge of the mandibular central incisors at the midline when the mouth is open as wide as possible is defined as maximum mouth opening (MMO). MMO is very important in the diagnosis of several clinical conditions such as temporomandibular joint (TMJ) disorders, odontogenic infections, facial trauma, neurological disorders, hyperplasia of coronoid process, pharmacological side effects, oral and neck cancers, radiotherapies, myopathies, oral malignancies, and rheumatic diseases.^{[1],[2],[3],[4],[5]} In addition, its value has been recognized in preoperative assessment before intubation for general anesthesia and before any dental or oral surgical procedure to determine access and visibility.^[6],[7] MMO is also important in following up on patient's undertreatment to check their progress and has a known implication in patient's normal life.

MMO is quite variable and can be related to many factors such as gender, age, and many anthropometric characteristics of a patient such as race, body height and weight, cranial base size, mandibular size, and joint condition.^{[2],[5],[8],[9],[10],[11],[12]} Few studies have been performed worldwide to determine the normal MMO in healthy individuals,^[13],[14] but more studies are required to quantify the variations between different populations. That is why we aim in this study to measure the MMO and to find its correlation to gender, age, and body weight and height in a randomly selected sample of Jordanian patients.

Materials and Methods

A total of 565 randomly selected Jordanian patients with an age range of 3–70 years old (191 male patients and 374 female patients) attending a comprehensive public health center (seeking dental treatment) were enrolled in this study. This public health center is considered a training center and provides health services within a large region in the city of Amman (the capital of Jordan). Patients agreed to participate in the study and demographic information was recorded.

Patients with missing teeth or incisor prostheses, severe attrition, orthodontic treatment, infection, history of facial trauma, tumor, TMJ symptoms, developmental facial anomaly or congenital anomaly affecting stature and systemic diseases such as rheumatoid arthritis or osteoarthritis, and pregnant women were excluded from the study.

The distance between the mesioincisal edge of the upper right central incisor and the mesioincisal edge of the lower right central incisor was used to calculate the mouth opening. MMO was measured using a calibrated fiber ruler while the patient seated comfortably in an upright relaxed position, gazing forward, and was instructed to open his or her mouth as wide as possible. Weight and height were taken using a medical scale. Single examiner (the author) made the clinical examination and interviews with patients.

Statistical analysis

Collected data were entered into a spreadsheet in SPSS software (Version 16.0; SPSS Inc., Chicago, IL, USA) for statistical analysis. Student's t-test was used to assess the statistical difference between MMO for males and females. Another t-test was used to assess the significant difference between MMO in each age group and MMO between males and females in each age group. Pearson correlation coefficient and a simple linear regression were used to assess the correlation between body weight and height and MMO.

Results

MMO was measured in 565 Jordanian patients (191 males and 374 females) with a mean age of 21.46 years. The average MMO for all patients was 45.01 ± 4.78 mm, and the average MMO for males (45.71 ± 5.29 mm) was statistically larger than the MMO of females (44.65 ± 4.46 mm; P = 0.13). There was an increase in the MMO value for patients in the 3–42 years old, followed by a decrease in this value after the age of 42 years, as shown in [Figure 1], but the t-test did not show that this difference was statistically significant (P > 0.05).

Figure 1: Comparison between mean male and female MMO values by the age group. MMO: Maximum mouth opening

Click here to view

[Figure 1] shows the comparison between mean male and female MMO values by the age group. There was a positive significant correlation between MMO and height (Pearson's correlation coefficient r = 0.242; P < 0.0001) as well as between MMO and weight (r = 0.209; P < 0.0001). Data are shown in [Figure 2] and [Figure 3].

Figure 2: Scatter and linear regression diagrams of MMO associated with height. MMO: Maximum mouth opening

Click here to view

Figure 3: Scatter and linear regression diagrams of MMO associated with weight. MMO: Maximum mouth opening

Click here to view

[Figure 2] shows scatter and linear regression diagrams of MMO associated with height.

[Figure 3] shows scatter and linear regression diagrams of MMO associated with weight.

From the linear regression model, equations were inferred by calculating regression coefficient and intercept for both height and weight as shown in the following equations: MMO (mm) =0.0539 × Height + 37.163 (P < 0.0001) and MMO (mm) =0.0391 × Weight + 42.996 (P < 0.0001). Hence, it was estimated that for every 10 cm or 10 kg, there is an increase in MMO of 0.5 mm or 0.4 mm, respectively.

Discussion

The normal range of mouth opening is a variable that shows up in all aspects of dental practice, especially maxillofacial and plastic surgery since it is both a diagnostic tool and a goal to achieve after treatment (i.e., to restore normal mouth opening). Hence, this value needs to be known by dentists and surgeons. The normal range of MMO was studied in some populations, but a limited number of studies were conducted in Middle Eastern countries.

Care should be taken when positioning the patient's head before making MMO measurements, as MMO can increase as head position changes from retracted to natural to forward position.^{[15],[16],[17]} That is why all patients were seated in a natural relaxed position looking forward before taking our own measurements. The methods described in the literature for measuring MMO are numerous. In this study, interincisal distance attained during active mouth opening by the patient was used, even if it underestimates the vertical distance traveled by the mandible in patients with a deep bite. This is because clinical importance lies in the functional opening of the mouth that actually affects chewing and dental treatment, not the distance that the mandible travels.^{[1],[2],[18],[19]}

Many tools have been described to measure the maximum interincisal distance. However, it was found that the ruler is an easier way and more accurate than the Willis gauge that requires a longer time and leads to fatigue and less cooperation from the patient.^[20] The mean value of MMO in our overall Jordanian subpopulation is 45.01 ± 4.78 mm (45.71 ± 5.29 mm in males and 44.65 ± 4.46 mm in females). These values are coherent with those obtained for the Saudi Arabian population,^[13] Swedish population,^[14] and Mexican population.^[21] Variations between studies in the mean value of MMO are due to sampling size, racial differences, facial morphology, and methods used to measure this value.

Male MMO is different from female MMO (especially in the younger age group), this is probably due to differences in mandibular size and whole skeleton,^[1],[2],[22] even though joint mobility is greater in females^[23] and the angle of opening at TMJ is higher.^{[18],[24],[25]} This conforms with our study, where we found a significant difference between males and females in all age groups, especially between 23 and 42 years old (P < 0.001). It is worth mentioning that some studies found no such gender difference.^[24],[26] Our study showed a trend of increasing MMO from 3 to 42 years old that is explained by the development of temporomandibular eminence.^{[19],[27],[28]} After that, MMO gradually decreases with the aging process as explained by skeletal muscle atrophy, declining strength, and degenerative changes as patient ages.^{[8],[18],[19]}

The correlation between MMO and either weight or height is debatable in literature. Some authors found that body height was strongly correlated with MMO.^{[10],[28],[29],[30]} Others found the correlation between MMO and both height and weight,^{[4],[22],[26],[28]} while Ying et al.^[12] found a significant correlation between MMO and weight but not height. However, Gallagher and Reicheneder et al. failed to find any association between weight and MMO.^[2],[11] In our study, a positive correlation was found between MMO and height (r = 0.242; P < 0.0001), and between MMO and weight (r = 0.209; P < 0.0001).

Limitations of this study include that the examined patients were recruited from a pool of patients seeking dental management in our department that represents one area of Jordan. Another is that radiographic images of TMJ were not collected to exclude any asymptomatic patients with mouth limitations, albeit a history of the absence of symptoms of temporomandibular dysfunction or trauma was taken to minimize this possibility. A larger sample and more areas of Jordan need to be studied to obtain nationwide results including more underlying factors such as cranial base length, mandibular size, and angle to confirm these findings.

Conclusions

Within the limitations of this study, we found a correlation between MMO and gender, height, and weight.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Cox SC, Walker DM. Establishing a normal range for mouth opening: Its use in screening for oral submucous fibrosis. Br J Oral Maxillofac Surg 1997;35:40-2.
2.	Chaudhary F, Ahmad B. Normal range of maximum mouth opening in Pakistani population: A cross-sectional study. J Int Oral Health 2019;11:353-6. [Full text]
3.	Sforza C, Tartaglia GM, Lovecchio N, Ugolini A, Monteverdi R, Giannì AB, et al. Mandibular movements at maximum mouth opening and EMG activity of masticatory and neck muscles in patients rehabilitated after a mandibular condyle fracture. J Craniomaxillofac Surg 2009;37:327-33.
4.	Li XY, Jia C, Zhang ZC. The normal range of maximum mouth opening and its correlation with height or weight in the young adult Chinese population. J Dent Sci 2017;12:56-9.
5.	Zawawi KH, Al-Badawi EA, Lobo SL, Melis M, Mehta NR. An index for the measurement of normal maximum mouth opening. J Can Dent Assoc 2003;69:737-41.
6.	Paix AD, Williamson JA, Runciman WB. Crisis management during anaesthesia: Difficult intubation. Qual Saf Health Care 2005;14:e5.
7.	Williamson JA, Webb RK, Szekely S, Gillies ER, Dreosti AV. The Australian Incident Monitoring Study. Difficult intubation: An analysis of 2000 incident reports. Anaesth Intensive Care 1993;21:602-7.
8.	Benevides S, Araújo RC. Determining the mandibular range of motions in children from Bahia state. Rev CEFAC 2016;18:95-103.
9.	Venkatraman A, Kaval F, Takiar V. Body mass index and age affect maximum mouth opening in a contemporary American population. J Oral Maxillofac Surg 2020;78:1926-32.
10.	Placko G, Bellot-Samson V, Brunet S, Guyot L, Richard O, Cheynet F, et al. Normal mouth opening in the adult French population. Rev Stomatol Chir Maxillofac 2005;106:267-71.
11.	Reicheneder C, Kardari Z, Proff P, Fanghaenel J, Faltermeier A, Römer P. Correlation of condylar kinematics in children with gender, facial type and weight. Ann Anat 2013;195:243-7.
12.	Ying QV, Bacic J, Abramowicz S, Sonis A. Cross sectional: Normal maximal incisal opening and associations with physical variables in children. Pediatr Dent 2013;35:61-6.
13.	Al-Dlaigan YH, Asiry MA. Maximum mouth opening in Saudi adolescents. J Int Oral Health 2014;6:45-9.
14.	Patel SM, Patel NH, Khaitan GG, Thanvi RS, Patel P, Joshi RN. Evaluation of maximal mouth opening for healthy Indian children: Percentiles and impact of age, gender, and height. Natl J Maxillofac Surg 2016;7:33-8. [PUBMED] [Full text]
15.	Eriksson PO, Häggman-Henrikson B, Nordh E, Zafar H. Co-ordinated mandibular and head-neck movements during rhythmic jaw activities in man. J Dent Res 2000;79:1378-84.
16.	Toro-Ibacache V, Zapata Muñoz V, O'Higgins P. The relationship between skull morphology, masticatory muscle force and cranial skeletal deformation during biting. Ann Anat 2016;203:59-68.
17.	Visscher CM, Huddleston Slater JJ, Lobbezoo F, Naeije M. Kinematics of the human mandible for different head postures. J Oral Rehabil 2000;27:299-305.
18.	Olufunmlayo OF, Oluwatosin AJ. A pilot study of the maximum interincisal distance among adult Northern and Southern Nigerians. Niger J Basic Clin Sci 2019;16:24-31.
19.	Sheppard IM, Sheppard SM. Maximal incisal opening – A diagnostic index? J Dent Med 1965;20:13-5.
20.	Wood GD, Branco JA. A comparison of three methods of measuring maximal opening of the mouth. J Oral Surg 1979;37:175-7.
21.	Koruyucu M, Tabakcilar D, Seymen F,Gençay K. Maximum mouth opening in healthy children and adolescents in Istanbul. Dent 3000 2018;6:122-4.
22.	AlHammad ZA, Alomar AF, Alshammeri TA, Qadoumi MA. Maximum mouth opening and its correlation with gender, age, height, weight, body mass index, and temporomandibular joint disorders in a Saudi population. Cranio 2021;39:303-9.
23.	Muto T, Kanazawa M. The relationship between maximal jaw opening and size of skeleton: A cephalometric study. J Oral Rehabil 1996;23:22-4.
24.	Loster J, Groch M. Assessment of the range of mandibular movements as related to gender in Polish young adult non-patients. J Stomatol 2016;69:146-52.
25.	Stålnacke C, Ganzer N, Liv P, Wänman A, Lövgren A. Prevalence of temporomandibular disorder in adult patients with chronic pain. Scand J Pain 2021;21:41-7.
26.	Steinmassl O, Steinmassl PA, Schwarz A, Crismani A. Dental age is more appropriate than chronological age for evaluating the mandibular movement range in children. J Craniomaxillofac Surg 2017;45:1201-4.
27.	Choi H, Kim C, Lee D. Measurement of maximum mouth opening in 2 to 6 year-old Korean children. J Korean Acad Pediatr Dent 2015;42:242-3.
28.	Landtwing K. Evaluation of the normal range of vertical mandibular opening in children and adolescents with special reference to age and stature. J Maxillofac Surg 1978;6:157-62.
29.	Fatima J, Kaul R, Jain P, Saha S, Halder S, Sarkar S. Clinical measurement of maximum mouth opening in children of Kolkata and its relation with different facial types. J Clin Diagn Res 2016;10:ZC01-5.
30.	Kumar A, Hooda A, Gulia J. Measurement and evaluation of the normal range of maximal mouth opening and its correlation with age, body height, weight, and gender in the young Indian population. J Oral Health Community Dent 2018;12:14-9.