Use of Arch Bars versus IMF-Screws in Maxillomandibular Fixation of Mandibular Fractures: A Randomised Prospective Study

Abstract

Background:

Traditionally, arch bars are used for mandibulomaxillary fixation (MMF) following mandibular fractures. Intermaxillary fixation screws (IMFS) are a suitable alternative to mitigate the drawbacks of arch bar fixation.

Aims and Objectives:

We compared the use of arch bars versus IMFS for treatment of mandibular fractures including evaluation of sonographic findings and the patients’ quality of Life (QoL).

Study Design:

This is a randomised prospective study.

Setting:

The study was conducted at the Department of Oral and Maxillofacial Surgery, University of Maiduguri Teaching Hospital.

Materials and Methods:

Fifty patients with mandibular fractures were recruited and randomly divided into two groups, 25 each in the arch bars and IMFS treatment groups. The parameters evaluated were as follows: mouth opening, malocclusion, pain, fracture healing using an ultrasound scanner, operating time, wire-prick injuries, oral hygiene, and QoL.

Results:

There was a significantly higher pain score by the 3^rd and 6^th postoperative weeks (P = 0.015 and P = 0.003, respectively) and shorter operating time (P < 0.001) in the IMFS group, while a notable higher wire-prick injury (P < 0.001) and poor oral hygiene (P = 0.25) were observed in the arch bar group. An ultrasound scan at 6 postoperative weeks showed complete hyperechoic bridging callus in (61.5%) the arch bar group and (50%) in the IMF screw group, with no statistically significant difference. Regarding the QoL, patients treated with arch bars had more difficulty in continuing with their normal diet and indicated “they will not undergo the same treatment again.” On the other hand, IMFS patients had significantly isolated themselves because of feelings of bad mood, and their sleep and speech patterns were significantly affected.

Conclusions:

Although some similarities were observed in both groups, this study observed that IMFS addressed some of the limitations associated with arch bars such as prolonged operative time, wire-prick injury, and poor oral hygiene. Therefore IMFS is relatively safer and can be used for long-time MMF.

Trial registration number:

PACTR202408851121914.

Date of registration:

04 July 2024, “retrospectively registered.”

Clinical trial registry:

Pan African clinical trials registry.

Introduction

The mandible is the prominent and mobile facial bone.[1,2] It contributes considerably to facial aesthetics and function. However, it is one of the most commonly fractured bones following trauma to the craniofacial complex.[3,4] Patients with mandibular fractures often face several problems that may impact their facial appearance, oral and masticatory functions, quality of life (QoL),[5] and depression.[6] Treatment of mandibular fractures requires adequate reduction, fixation, and immobilisation through the close or open technique. Traditionally, close reduction (CR) and mandibulomaxillary fixation (MMF) have been achieved using arch bars,[7,8] particularly in low-resource environments.[9] Several associated challenges have, however, been reported with this modality of treatment. This includes increased risk of puncture injuries to the operators, increased operative time, trauma to the oral soft tissues, compromised oral hygiene, and impaired pulmonary function.[8,10,11,12]

The introduction of intermaxillary fixation screws (IMFS) – a bone-borne device introduced by Arthur and Bernando in 1989 –[13] has addressed some of these issues associated with arch bars.[14] They have since been used as an alternative to arch bars in treating mandibular fractures.[7] Consequently, many studies have compared the use of arch bars and IMFS in the management of mandibular fractures.[8,10,14,15] However, most of these studies only make use of objective clinical signs assessed by the clinician.[10,11,16] Moreover, objective treatment outcome measures have been challenged that in most instances, they do not correlate with the patient’s perception of health and general wellbeing, and hence their QoL.[17]

This study investigates the efficacy of IMFS in comparison with that of arch bars. Specifically, the intent is to compare both the objective treatment outcomes measured by the clinicians and the subjective assessment outcomes according to patients providing a comprehensive picture of the treatment outcomes of the two different treatment methods.

Materials and Methods

This randomised prospective study compared objective treatment outcomes and QoL in patients with mandibular fractures treated with CR and MMF using either arch bars or IMFS. This study was performed in line with the principles of the Declaration of Helsinki. Ethical approval was granted by the Institutional Ethical Committee, and informed consent was obtained from all individual participants included in the study.

Inclusion criteria

Patients were recruited into this study based on the following inclusion criteria; mandibular fracture that is simple, unilateral, undisplaced, or minimally displaced that occurred in the symphysis, parasymphysis, or body of the mandible.

Exclusion criteria

However, multiple, comminuted, or pathologic fractures and patients with associated head injury, systemic debilitating diseases, or known tobacco smokers were excluded from the study.

Sample size calculation

The sample size was determined using the formula:

Assuming alpha = 0.05

Power = 0.80 (beta = 0.20)

where n = sample size per group

a = 1.96

b = 0.842

σ= 3.4 (Sudheesh KM et al[18])

n ≈ 20 subjects per group

20% increase to allow for subject dropout

Approximately 25

Therefore, n = 25 subjects per group

Randomisation

A total of 50 adult patients aged 18–65 years were included in the study. Using a table of random numbers (RAND Cooperation 1955), a consecutive order of participants were randomly allocated serially into two treatment groups, A and B, representing those treated with arch bars and IMF screws, respectively.

Operative technique

The patients in the arch bar treatment (group A) had their mandibular fractures manually reduced under local anesthesia (2% lignocaine 1:100,000 adrenaline (Alphacaine 100) (DFL industria Comercio S.A Brasil). An appropriate dental occlusion was used as the clinical guidance of satisfactory fracture reduction. Prefabricated Erich arch bars are contoured to fit the dental arch curvature and thereafter ligated to the external surface of the dental arch by passing 0.5-mm soft stainless steel wires around the necks of the teeth, with one end of the wire passed under the arch bar, and the other end was passed over the arch bar. The wires are then twisted tightly to individual teeth to hold the arch bars. MMF was achieved using wires inserted between the cleats of the upper and lower arch bar. The wires are first pulled, tightened, and then cut in a way so that the sharp ends of the wire are twisted and angled into the interdental area to avoid any soft tissue laceration [Figure 1].

Figure 1.

Mandibular parasymphysial fracture treated with arch bar fixation

The patients in the IMF screw treatment (Group B) had their mandibular fractures manually reduced under local anesthesia. A stab incision was made at the mucogingival junction, followed by the drilling of the alveolar bone with a 1.5-mm drill bit to allow for the placement of IMF screws. A total of four IMF screws were inserted (Johnson and Johnson DePuy Synthes IMF screw; 2.0mm IMF screw, self-drilling, 8 and 12 mm), one in each quadrant either medially or laterally to the canine root in the maxilla and also in the mandible. Additional screws were inserted on the contralateral side, one in the maxilla and one in the mandible, while avoiding the roots of the teeth and the mental nerve in the mandible. However, the number and position of the IMF screws were sometimes adjusted, depending on the fracture type and location. Adequate reduction of the fracture was established before the screws placed in the maxilla and mandible were ligated together with a 0.5-mm soft stainless steel ligature wire in a vertical and X-pattern according to the technique described by DePuy Synthes CMF.[19] to achieve proper dental occlusion [Figure 2].

Figure 2.

Mandibular parasymphysial fracture treated with intermaxillary fixation screws

The screws and arch bars were left in place for 6 postoperative weeks.

All the MMF procedures and postoperative evaluations were performed by the first author, while all the sonographic examinations and interpretation were performed by the third author.

The primary objective outcome assessed includes the following:

• I.Maximum interincisal distance: measuring the distance from the mesio-incisal edge of the upper central incisor to the mesio-incisal edge of the lower central incisor using a vernier calliper to measure the degree of postoperative mouth opening.
• II.Patient’s occlusion: we ask and guide the patients to close their teeth as possible to establish their pre-trauma occlusion based on the molar–incisor association, and MMF is then achieved using the same established maxillar–mandibular relationship. After releasing the MMF in the 6^th postoperative week, the patient’s occlusion is then evaluated based on the previous record of occlusion coupled with the patient’s satisfaction with his occlusion. The outcome is, therefore, graded as present or absent of occlusal derangement (as noted by the examiner or complaint by the patient).
• III.Postoperative pain was assessed using the Numerical Rating Scale (NRS). Subjects were asked to circle the number between 0 and 10 that fit best to their pain intensity, 0 represents “no pain at all,” whereas the upper limit represents ‘the worst pain ever possible,’ and records were taken on the day 1, day 3, week 3, and week 6 postoperatively.
• IV.Evaluated postoperative fracture healing using an ultrasound scanner (USS); GE logic S8 equipped with a broadband linear transducer, frequency 6–15 MHz at the immediate postoperative period and weeks 3 and 6. During the scan, the ultrasonic probe is placed at the lower border of the mandible at the fractured site perpendicular to the long axis of the related teeth [Figure 3]; on the image displayed on the screen, the fractured bone surfaces and contiguous healthy bone will be captured. Then, the measurement of the fracture gap was taken from edge to edge of the adjacent healthy bone in millimetres using an ultrasonographic Calliper. In addition, qualitative evaluation of bone union was performed and categorised as complete, partial, or absence of a hyperechoic bridge at weeks 3 and 6.

Figure 3.

Patient undergoing scanning of the mandibular symphyseal fracture (Note: the position of the probe at the fractured site perpendicular to the long axis of the associated teeth)

The secondary objectives’ outcome measures include operating time, wire puncture injuries, oral hygiene (using the simplified oral hygiene index by Greene and Vermillion scale 1964), screw fracture and screw-covered mucosa, paresthesia, and infection.

For the subjective outcome, evaluation was done by the self-report English questionnaire designed by Savin and Ogden.[20] The questionnaire comprised five domains: social isolation, isolation from work, functional domain, appearance, and satisfaction. The questionnaire was completed at postoperative weeks 1, 3, and 6.

Statistical analysis

Data collected were entered into SPSS for Windows (version 21.0 SPSS Inc. Chicago, IL, USA). The Mann–Whitney U test was used to compare the differences between continuous and ordinal variables, and the Wilcoxon Signed-Rank test was used to compare the postoperative mouth opening and fracture gap within the group. The chi-square test was used to compare categorical variables. For all the tests, P value <0.05 was considered statistically significant.

Results

Fifty-six patients met the inclusion criteria for this study; however, two patients declined to participate (one each from each group), while four (one from group A and three from group B) were not able to complete follow-up appointments and were excluded. Fifty patients consisted of 44 male patients and six females, and the median age of patients was 25.5 years, which was observed to be similar in the two groups with no statistically significant difference (P = 0.969) [Table 1].

Table 1.

Distribution of patient’s age and sex

	Arch bar (n = 26)	IMF screw (n = 24)	Total (50)	P value
Age (years)	25.5 (15.5)	25.5 (11)	25.5 (12)	0.969*
Sex	26	24	50	0.627‡
Male	23	21	44
Female	3	3	6

Results presented as median (Interquartile range)

^*Mann–Whitney U Test

^‡Chi-square test X²

Comparison of treatment outcome and arch bar versus IMFS

The median working time for placement and removal of IMFS was significantly shorter than that in the arch bar (P < 0.001) [Table 2]. The median maximal interincisal opening at 6 weeks was similar in both groups (IMFS – 41 mm; arch bar – 44 mm), and this improved further to (48 mm and 47.5 mm, respectively) by the end of 8 weeks. Postoperative pain analysis showed no significant difference in the pain scores at 1 day and 3 (P = 0.087 and P = 0.490, respectively) in both groups [Table 2]. However, a statistically significant higher pain score was observed in patients in the IMFS group when compared with the arch bar group at the end of 3^rd weeks and 6^th weeks (P = 0.015 and P = 0.003, respectively).

Table 2.

Comparison of objective treatment outcomes between arch bar and IMF screw subjects

Variable	Arch bar	IMF screw	P value
Mouth opening
Preoperative	33 (7.0)	30 (11)	0.261
6 weeks postoperative	44 (6.3)	41 (8.5)	0.605
8 weeks postoperative	47.5 (11)	48 (5)	0.822
+P Value	<0.0001	<0.0001
Occlusal derangement	0 (Yes)	1 (YES)	0.225‡
Pain (NRS)
Preoperative	4.5 (1)	5 (2)	0.199
1 day postoperative	2 (0)	2 (1.75)	0.087
3 days postoperative	0 (1)	0 (0)	0.490
3 weeks postoperative	0 (0)	0 (0)	0.015
6 weeks postoperative	0 (0)	0 (1)	0.003
Ultrasound evaluation of healing:
Healing Gap (mm)
Immediate postoperative	1.4 (1.45)	1.8 (0.93)	0.272
3 weeks postoperative	0.8 (0.70)	1.0 (0.82)	0.081
6 weeks postoperative	0.0 (0.88)	0.2 (0.40)	0.910
P value	<0.001	<0.001
Hyperechoic bridge (3 weeks)			0.514‡
Absent	5 (19.2%)	5 (20.8%))
Partial	20 (76.9%)	19 (79.2%))
Complete	1 (3.8%)
Hyperechoic bridge (6 weeks)			0.412‡
Absent	0	0
Partial	10 (38.5%)	12 (50%)
Complete	16 (61.5%)	12 (50%)
Insertion and removal time (mm)
Insertion time	70 (9)	20 (7.5)	<0.001‡
Removal time	20 (5)	8 (4.5)	<0.001‡
Wire-prick injury/ Gloves perforation	21	1	<0.001‡
Oral hygiene			0.025‡
Good	0	1
Fair	8	15
Poor	18	8
Screw covered by mucosa	-	11
Screw fracture on insertion	-	1
Infection	1	0	0.520‡
Paresthesia	0	0
Iatrogenic injury to dental root	-	0

Results presented as median (Interquartile range)

^*Mann Whitney U Test

^‡Chi-square test X²

⁺Comparison between 6 and 8 weeks postoperative mouth opening (Wilcoxon Signed-Rank Test) bold values= significant (P < 0.05)

Immediate postoperative ultrasound assessment shows a baseline gap of 1.4 mm and 1.8 mm for the arch bar and IMFS, respectively. There was evidence of gradual bone healing in both groups at 3 and 6 weeks [Figure 4]. At 6 weeks, complete hyperechoic bridging callus was observed in two out of every three patients in the arch bar and one in every two patients in the IMFS group.

Figure 4.

Ultrasound scan assessment of fracture healing (IMFS); a1. Immediate postoperative fracture gap. a2. partially formed callus at the fracture area (arrow indicating callus formation) at 3rd week. 4a3. complete healing of the fractured mandible (arrow indicating callus formation) at 6th week. Ultrasound scan assessment of fracture healing (arch bar group); b1. Immediate postoperative fracture gap. b2. partially formed callus at the fracture area (arrow indicating callus formation) at 3^rd week. b3. complete healing of the fractured mandible (arrow indicating callus formation) at 6^th week

The wire prick injury or glove perforation to the operators during arch bar fixation was found in 21 patients (57.14%) and only one in the IMFS group (P < 0.001) with a statistically significant difference (P < 0.001). On the 6th postoperative week, the oral hygiene status was poor in 69.2% of arch bar patients compared to the 33.3% of those in the IMFS group. Eleven (45.8%) patients in the IMFS group had screw heads covered by mucosa [Table 2].

Comparison of quality of life in the arch bars versus IMF screw group

Table 3 contains data for dichotomous variables. Patients at week 1 reported social isolation in both groups; however, patients who underwent IMFS fixation had significantly reported a feeling of a bad mood as the reason for isolation (P = 0.048), compared to those in the arch bar group who reported appearance as a major reason for isolation (P = 0.093). In the 6^th week, patients in the arch bar group reported less willingness to undergo the same treatment compared to the IMFS group (P = 0.050).

Table 3.

Comparisons of QoL between Arch Bar and IMF Screw Subjects (for dichotomous variables)

	Week 1	p value	Week 3	p value	Week 6	p value
	Percentages		percentages		percentages
Socially isolated:
1a. Did you continue your normal daily activities?	0.0% vs 8.3%	0.225	53.8% vs 41.7%	0.389	73.1% vs 66.7%	0.621
1b. Did you continue your daily sports activities and hobbies?	0.0% vs 12.5%	0.103	23.1% vs 20.8%	0.848	38.5% vs 45.8%	0.598
Give reason for social isolation:
1c. Pain and/or swelling	73.1% vs 54.2%	0.164	0.0% vs 12.5%	0.103	3.8% vs 12.5%	0.340
1d. Appearance	96.2% vs 79.2%	0.093	84.6% vs 70.8%	0.242	57.7% vs 37.5%	0.153
1e. Bad mood	57.7% vs 83.3%	0.048*	26.9% vs 50.0%	0.093	11.5% vs 0.0%	0.236
1f. Discomfort (flu-like)	76.9% vs 66.7%	0.420	50% vs 50%	1.000	19.2% vs 25.0%	0.623
Isolation of work:
2a. Did you ask for sick leave or did you temporarily stop working?	100% vs 91.7%	0.225	46.2% vs 62.5%	0.247	19.2% vs 25.0%	0.623
2c. Did your operation influence your work?	100% vs 100%	-	57.7% vs 66.7%	0.514	42.3% vs 58.3%	0.258
2d. Did someone accompany you?	100% vs 100%	-	84.6% vs 79.2%	0.721	53.8% vs 66.7%	0.355
2e. Did the person have to cancel his or her job to accompany you?	100% vs 100%	-	88.5% vs 79.2%	0.456	42.3% vs 66.7%	0.084
Satisfaction with the given treatment:
7a. Are you satisfied with your treatment?					100% vs 100%	-
7b. Would you recommend this treatment to someone else?					84.6% vs 95.8%	0.351
7c. Would you undergo the same treatment again?					73.1% vs 95.8%	0.050*
7d. Do you think the problem that needed treatment, is solved?					100% vs 100%	-

Chi-square test performed, percentages of subjects that answered `Yes` (Arch bar vs IMF screw, P value),

^* = significant (P value <

For ordinal variable analysis (week 1), patients who had undergone IMFS treatment were significantly able to continue with a normal diet (P < 0.0001) compared to arch bar group patients, but experienced difficulty in falling asleep (P = 0.038). At week 6, a statistically significant difference was observed in the IMFS group regarding the difference they noticed in their ability to speak when compared with the arch bar group (P = 0.003) [Table 4].

Table 4.

Comparison of QoL between Arch Bar and IMF Screw Subjects (ordinal variables)

No.	Question	Week 1	Week 3	Week 6
3a	Did you continue your normal diet?	<0.001*	0.845	0.327
3b	Did you notice any difference in your ability to taste/ taste perception?	0.621	0.620	0.521
4a	Did you notice any difference in your voice?	0.153	0.455	0.631
4b	Did you notice any difference in your ability to speak?	0.406	0.925	0.003*
4c	When you speak to others, do they understand you?	0.577	0.080	0.220
5a	Did you experience problems falling asleep?	0.038*	0.814	0.572
5b	Did you experience interruptions during your sleep?	0.320	0.428	0.220
5c	Was your sleep refreshing?	0.713	0.518	0.516
6a	Did you experience any change in appearance?	0.557	0.246	0.121
6b	Did you expect this appearance?	0.226	0.375	0.648

Mann–Whitney U test performed.

^* Significant (P < 0.05)

Discussion

This study compared the outcomes of mandibular fractures treated with MMF using arch bars and IMFS from the perspectives of healthcare practitioners and patients. Unlike objective treatment outcomes, the patients’ perspectives of treatment outcomes have received less attention in the literature.[14,21]

There is a paucity of information in the literature assessing the degree of mouth opening using IMFS in the treatment of mandibular fractures. In this study, at 6 weeks, adequate mouth opening was observed in both groups (IID >35mm), and the difference was not significant statistically. Contrarily, Anslem et al.,[22] reported limitation of mouth opening (IID of 23.6 ± 5.8 mm) in patients with IMFS. This difference may be possible because we encouraged and supervised our patients to do some passive jaw exercises at least 15 min before we took the measurement. Limitation in mouth opening is due to disuse atrophy of the muscles related to mastication as a result of this 6-week periods of immobilisation, which can be improved with adequate jaw exercises.[23]

Compared with arch bars, some studies have claimed that the IMFS system does not reliably approximate fractures and cannot evenly distribute the forces between the maxillary and the mandibular teeth when used in the treatment of mandibular fractures.[15,24,25] If the forces cannot be evenly distributed, occlusion problems may occur.[15,25] In our study, a malocclusion rate of 4% in the IMFS was observed and none in the arch bar group. The low incidence of occlusal problems in this study could be explained by the strict inclusion criteria, which limited our cases to only uncomplicated fractures in the tooth-bearing region of the mandible. In similar recent studies, Fernandes et al.,[26] and Park et al.[27] reported no significant differences in occlusal stability between the two treatment groups.

Although pain scores measured in the postoperative day 1 were the same for both groups, some subjects in the IMFS group, however, reported a significant increase in pain at the 3^rd and 6^th postoperative weeks. This could be related to high complications of mucosal overgrowth on the screw heads, with subsequent inflammation setting in. Contrarily, Bergh et al. in their study reported a lower incidence of pain in IMFS to compared to the arch bar group.[10] Mucosal overgrowth is, therefore, observed to be a major disadvantage of using IMFS for prolonged periods in the management of mandibular fracture.

Ultrasound was used for assessment of fracture healing in this study because of its simplicity, non-radiative nature, and rapidity in the observation of fracture healing when compared with plain radiographs.[28] The role of ultrasound imaging is increasingly valued in monitoring bone healing following surgical treatment in long bones,[28,29] with sparse data regarding similar use in the maxillofacial region.[30]

The baseline median fracture gap score for the arch bar group (1.4 mm) was slightly less than that of the IMFS (1.8 mm) during the immediate postoperative period, with no significant difference statistically. Furthermore, at weeks 3 and 6, the median fracture gap score in the arch bar group significantly reduced to 0.8 mm and 0.0 mm, respectively (P < 0.001) and that of the IMFS group decreased to 1.0 mm and 0.2 mm, respectively (P < 0.001). In addition, quantitative assessment of healing by ultrasounds shows that complete bridging callus was observed in (61%) and (50%) of patients in the arch bar [Figure 4b] and IMFS group [Figure 4a], respectively, at postoperative week 6. There was no significant difference between the groups (P = 0.412). Our study has demonstrated that ultrasonography can be used as an adjunct to the clinical assessment in monitoring healing of the fracture of jaw bones, similar to findings of studies in the other part of the body.[31]

This study shows that MMF with IMFS has a significantly shorter duration for insertion and removal. The relatively faster working for IMFS was consistent with the data from previous studies.[11,21,32] Prolonged operative time can increase risks of prolonged exposure of patients to anesthesia, extreme fatigability, and higher costs.[11,33]

The significantly higher incidence of wire-prick injuries or glove perforation to the operators reported in the arch bar group in this study is in line with the findings in several similar studies[8,10] Passing wires interproximally have been suggested to produce a high risk for wire-stick injuries in arch bar fixation.[34] The need to take adequate precautions to prevent the transmission of blood-borne pathogens during arch bar placements cannot be overemphasised.

We recorded a relatively high occurrence of mucosal overgrowth (46%) in IMFS patients similar to previous studies.[10,32] Most studies that reported high rates of mucosa overgrowth placed the screws in the alveolar mucosal region.[14,32] Some studies suggested that the placement of screws at the mucogingival junction could minimise this complication.[19,35] Although all the IMFS in this study were inserted at the mucogingival junction, the large proportion of screw-covered mucosa may be due to our stab-induced incision on the mucosa to facilitate ease of bone drilling and also to our prolonged periods of immobilisation. Therefore, a self-drilling screw, which may not necessarily need an incision to pierce the mucosa and engage the bone, can minimise this complication.

Another complication associated with IMFS fixation is the breakage of the screw on insertion. Coburn et al.[36] suggested that these complications could be avoided by careful and slow drilling under copious irrigation with sterile saline and by not forcing the screw if resistance is encountered. In the present study, only one case of screw fracture was recorded.

We also found significantly poor oral hygiene in the arch bar group, which was similarly observed in previous studies.[32,37] Oral hygiene is easier to maintain when less hardware is covering the teeth, resulting in better oral hygiene scores for IMFS which is a bone-borne appliance.

The QoL aspect of our assessment highlighted that social isolation was present in both groups. The participants experienced social difficulties due to the effects of the treatment on interpersonal relationships and daily activities. The predominant reason varies and includes the feeling of bad mood, which was significantly higher in IMFS patients; although isolation due to an appliance was higher in the arch bar group in week 1, there was a gradual improvement by the 6^th week. The substantial improvement by the 6^th week possibly suggests adaptation to the reality of individual treatment methods.

Similar to the findings by Van Den Bergh et al., at week 1, patients treated with either IMFS or arch bars (92% and 100% respectively) had substantial time off work either by asking for sick leave or stopped working temporarily, and no statistically significant difference was observed. These findings would imply that both treatment methods had similar economic disadvantages, especially on daily income earners who had to stay off the business until fully recovered. Some studies have, however, suggested treatment with IMFS leads to a lower financial impact on the patient when compared with treatment with arch bars.[21]

Reports have shown that long-time MMF for the management of jaw fractures can lead to compromised nutritional intake and consequent weight loss.[38] In the present study, when compared with patients treated with arch bars, significantly more patients treated with IMFS believed that they were able to continue a normal diet and experience fewer problems with eating (P < 0.0001). This is in agreement with the findings by Van Den Bergh et al.

IMFS patients were significantly more affected in their ability to speak at week 6 compared to the arch bar treatment group. The reason may be that pain was also significantly higher in the IMFS group in the 6^th week, which may be attributed to inflammation of the mucosa covering the screw head.

IMFS patients reported significantly more problems in sleeping compared to the arch bar in week 1. This is contrary to the observation by Van Den Bergh et al. The affectation of sleep in the early postoperative period in IMFS patients may be due to the bad mood experience discussed earlier.

Concerning satisfaction with the treatment, 95.8% of IMFS patients said they would undergo the same treatment again compared to 73.1% of patients in the arch bar group (P = 0.050). It would seem that this response is an indication of the degree of discomfort endured by patients in each of the groups. The willingness to repeat the operation in a relatively larger number of patients in the IMFS group could be inferred to mean that the experience had not been unacceptable.

Conclusion

The IMF screw system could be a valid alternative to the arch bar in the treatment of simple mandibular fractures. The present study observed that IMF screws have similar occlusal stability, postoperative degree of mouth opening, and mandibular fracture healing as arch bars when used for long-time immobilisation in the management of mandibular fracture. IMFS can, however, be a preferred treatment option in settings where there is concern of blood-borne disease transmission, oral hygiene maintenance, and when shorter operative time is desired.

Ethical approval

This study was performed in line with the principles of the Declaration of Helsinki. Ethical approval was granted by the Institutional Ethical Committee (UMTH/REC/617)

Consent to participate

Informed consent was obtained from all individual participants included in this study.

Consent to publish

The authors affirm that human research participants provided informed consent for the publication of the images in Figures 1,2,3.

Author contributions

All authors contributed to the study’s conception and design. Conception, study design, and material preparations were performed by Dr. Mukhtar Modibbo Ahmad, Dr Olutayo James, and Dr Abubakar Farate. Data collection and analysis by Dr Ibrahim Kayode Suleiman and Dr Mohammed Adam Sheikh Abdullahi while critical revision and edition by Dr Hector Oladapo Olasoji and Dr Farouk Kabir Umar.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.