Crown Discoloration as A Sequelae of Traumatic Dental Injuries

Joan  Enabulele; Mohammed Bi

doi:10.31487/j.DOBCR.2019.02.05

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Crown Discoloration as A Sequelae of Traumatic Dental Injuries

A B S T R A C T

Background:Crown discoloration is one of the complications associated with traumatic dental injuries. It is the external expression of changes in the pulp- dentine complex that becomes visible through the translucent enamel. It is a sign of internal damage, but not necessarily irreparable damage.
Objective:: To determine the prevalence of crown discoloration following traumatic dental issues and possible factors associated with crown discoloration
Methods:A prospective cross-sectional study of patients with traumatic dental injuries. The crowns of all anterior teeth were examined for signs of trauma. Visual colour determination was done using visual comparison of the traumatized tooth crown red with the contralateral tooth if unaffected or adjacent unaffected tooth. Tooth crown colour was classified as normal or discoloured. Data was subjected to descriptive analysis in the form of frequencies, percentages, mean, standard deviation and cross tabulations. Chi square was used to determine association between variables with p set at 0.05. Logistic regression was used to identify significant predictors of tooth discoloration following traumatic dental injury.
Conclusion:Crown discoloration is a significant sequela of traumatic dental injury. Level of education is associated with presenting with a discoloured traumatised tooth. Gender, age and level of education are predictors of patients presenting with discoloured traumatised teeth.

Keywords

Dental trauma,crown discoloration,sequelae

Introduction

Traumatic dental injuries (TDIs) are injuries to the teeth and/ or surrounding tissues. The prevalence of which varies from study to study and from country to country. Studies have reported frequencies ranging from 10.2 to 69.2% [1-3]. These variations reflect cultural and environmental difference and the use of different methods of data collection in each study. In Nigeria the prevalence of traumatized anterior teeth in the rural population was reported to be 6.5% while it was reported to be 14.5% in the metropolitan population [4, 5]. Discoloured anterior teeth can be considered as a significant aesthetic impairment which can compromise patients� appearance. Crown discoloration is one of the complications associated with traumatic dental injuries. It is the outward expression of pathology in the pulp- dentine complex which turn out to be visible to the eyes through the enamel due to its translucent nature. Though, it is an insignia of internal damage, it however does not essentially translate to irreversible damage [6].

Tooth crown discolouration might be the consequence of pulp canal space obliteration which occurs due to the filling of the pulp cavity with dark tertiary dentine with resultant tooth crown with less translucent appearance [7]. Formation of excessive irregular dentin in the pulp chamber and along the canal walls may occur following certain traumatic injuries; this is known as calcific metamorphosis [8]. When the permanent teeth have a greyish hue, it is suggestive of pulp necrosis, while a yellowish hue shows that widespread calcification may have occurred [9]. When the pulp is necrosed, there is release of disintegration by-products that may infiltrate tubules and discolour the surrounding dentine. The degree of discolouration is directly linked to how long the pulp has been necrotic [10]. A red discolouration may appear almost immediately after a luxation injury. This discolouration is predicted to occur when a minor luxation injury severs the veins in the apical foramen and the arteries continue to carry blood into the pulp [6]. Successive disintegration of blood gradually results in a bluish or bluish/brown discolouration.

Acute trauma to an erupted tooth can cause intra-pulpal hemorrhage giving it a reddish tinge. This discoloration can change to grey-brown in a matter of days as the pulp becomes necrotic. Bacterial, mechanical or chemical irritation to the pulp may also result in tissue necrosis and the release of disintegration by-products that infiltrate the tubules with subsequent discolouration of the surrounding dentin. The attendant haemolysis of the red blood cells causes the release haem which in turn combines with the putrefying pulpal tissue to form black iron sulphide [11]. Grossman asserted in 1943 that the depth of dentinal penetration determines the degree of discolouration [12]. The loss of hard dental tissues as a result of osteoclastic activities (root resorption) is either a physiologic or pathologic process taking place internally (pulpally-derived) or externally (periodontally-derived) with subsequent loss of dentin, cementum or bone [13]. Internal inflammatory root resorption (IRR) is branded by progressive loss of tooth substance beginning from the root canal wall [14]. IRR, also known as pink tooth of Mummery, named after the anatomist Mummery, is usually asymptomatic, slowly progressing, and noticeable upon routine radiographic examination or by the clinical sign of a �pinkspot� when it involves the crown or the coronal third of the root canal [15]. The process of resorption is initiated by a variety of stimuli such as trauma, pulpotomy, extreme heat during cutting of dentine, chronic inflammation of the pulp following caries, periodontal infections, orthodontic treatment, calcium hydroxide procedures, vital root resections, tooth transplantation, crack tooth [16].

There is a paucity of studies on factors associated with crown discoloration following traumatic dental injuries. Hence this study which is aimed at determining the prevalence and pattern of crown discoloration following traumatic dental issues. It also will assess possible factors associated with crown discoloration.

Materials and Methods

This was a prospective cross-sectional study of patients who presented with traumatic dental injuries to the University of Benin Teaching Hospital. The data for the study was obtained by using an interviewer administered questionnaire which consisted of five sections: socio-demographic characteristics, mechanism of injury determined through the history, findings on examination and investigation (pulp sensibility testing and radiographs) and tooth shade assessment. The patients were examined with the initial examination being systematic and comprehensive. The crowns of all anterior teeth were examined for signs of trauma. Visual colour determination was done using visual comparison of the traumatized tooth crown red with the contralateral tooth if unaffected or adjacent unaffected tooth. Tooth crown colour was classified as normal or discoloured. The discoloured crowns were documented as yellow, red, grey or dark. Two examiners who did not have history of colour blindness were trained for this assessment.

The data so obtained was subjected to statistical analysis using IBM SPSS version 21.0. The statistics carried out were descriptive analysis in the form of mean, standard deviation, frequencies, percentages, and cross tabulations. Chi square was used to determine association between variables with p set at 0.05. Logistic regression was used to identify significant predictors of tooth discoloration following traumatic dental injury.

Figure 1: Presenting complaints among the participants

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Figure 2: Aetiology of the traumatic incident among the participants

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Results

A total of 161 participants with a total of 279 traumatised teeth were recruited for the study. There was slight female preponderance with male female ratio of 1:1.01. Most (73.9%) of the participants had tertiary education and 71.4% were single. Almost half (49.1%) of the participants were dependents and most of them were less than 40 years old (Table 1). The participants age ranged from 17 to 69 years with a mean age of 30.7�11.3years. The time elapsed between the traumatic incident and presentation for treatment ranged from 1 day to 40 years post traumatic incident with mean time elapsed of 6.9years �9.14years. The most common presenting complaint among the participants was disfigured teeth accounting for 42.2%, pain was reported by 34.8% and discoloured teeth by 6.8% (Figure 1). Various aetiologies were responsible for the traumatic incident. Road traffic accident was the most common aetiology reported (27.3%), this was followed closely by falls (26.7%) while sporting/playground activities was the least reported aetiology accounting for 6.2% (Figure 2). The prevalence of tooth discoloration following trauma to the anterior teeth was 33.5%. There was statistically significant association between the occupation of the participants and presenting with discoloured traumatised anterior teeth. A higher proportion of professionals and skilled workers presented with discoloured traumatised teeth (Table 2). Table 3 shows the association between the presenting complaint as well as the aetiology of the traumatic incident and presence of discoloured traumatised anterior teeth among the participants. All participants whose presenting complaints were either swelling or discoloured teeth all had tooth discoloration, and this was statistically significant. The aetiology of the traumatic incident had no significant association with the presence or absence of a discoloured traumatised tooth.

Table 1: Socio-demographic characteristics of the participants

Characteristics	Frequency	Percent
Age group (years) ≤ 25	68	42.2
26-40	68	42.2
>40	25	15.5
Gender Male	80	49.7
Female	81	50.3
Highest level of Education Primary	6	3.7
Secondary	36	22.4
Tertiary	119	73.9
Marital status Single	115	71.4
Married	46	28.6
Occupation Professional	11	6.8
Skilled worker	46	28.6
Semi-skilled worker	8	5.0
Unskilled worker	17	10.6
Dependents	79	49.1
Total	161	100.0

Table 4 shows that the mean time elapsed between the traumatic incident and presentation for treatment was higher for those whose traumatised teeth became discoloured than those whose teeth were not discoloured, a difference which was statistically significant (P=0.001).

Logistic regression performed showed that 66.5% of the overall percentage was correctly classified. The model did a good job of predicting crown discoloration of traumatised teeth among the participants (Omnibus test of model coefficient 0.000). The Cox and Snell R Square was 0.314 while the Nagelkerke R Square was 0.435 indicating that between 31.4% and 43.5% of the variability in the dependent variable was explained by the model. Hosmer-Lemeshow test (0.95) showed that the model was well-fitted. The result of the model building after the predictor variables were introduced into the analysis showed that the model was doing a better job of correctly predicting the outcome than when no predictor variable was built into the model (overall percentage78.3). The higher the age of the participants the less the likelihood of having traumatised teeth becoming discoloured. The odds for a female to have traumatised teeth becoming discoloured was 2.642 times higher than the odds for a male and this was statistically significant (p=0.03). The odds for a semi-skilled worker to have traumatised teeth becoming discoloured was 3.759 times higher than the odds for a professional and this was statistically significant (p=0.03). Gender, profession and time elapsed were predictive of traumatised teeth becoming discoloured (Table 5).

Table 2: Association between socio-demographic characteristics and presence of crown discoloration

Characteristics	Crown discoloration		Total n (%)
Characteristics	No n (%)	Yes n (%)	Total n (%)
Gender Male	53 (66.3)	27 (33.8)	P=0.96 80 (100.0)
Female	54 (66.7)	27 (33.3)	81 (100.0)
Age group (years) ≤ 25	50 (73.5)	18 (26.5)	P=0.1 68 (100.0)
26-40	39 (57.4)	29 (2.6)	68 (100.0)
>40	18 (72.0)	7 (28.0)	25 (100.0)
Occupation Professional	6 (54.5)	5 (45.5)	P= 0.016 11 (100.0)
Skilled worker	23 (50.0)	23 (50.0)	46 (100.0)
Semi-skilled worker	8 (100.0)	0 (0.0)	8 (100.0)
Unskilled worker	12 (70.6)	5 (29.4)	17 (100.0)
Dependents	58 (73.4)	21 (26.6)	79 (100.0)
Highest education Primary	6 (100.0)	0 (0.00	P=0.204 6 (100.0)
Secondary	23 (63.9)	13 (36.1)	36 (100.0)
Tertiary	78 (65.5)	41 (34.5)	119 (100.0)
Marital status Single	80 (69.6)	35 (30.4)	P=0.187 115 (100.0)
Married	27 (58.7)	19 (41.3)	46 (100.0)
Total	107 (66.5)	54 (33.5)	161 (100.0)

Table 3: association between presenting complaint, aetiology of the traumatic incident and presence of crown discoloration

	Crown discoloration		Total n (%)
	No n (%)	Yes n (%)	Total n (%)
Complaint Pain	39 (69.6)	17 (30.4)	P<0.0001 56 (100.0)
Swelling	0 (0.0)	11 (100.0)	11 (100.0)
Discoloured teeth	0 (0.0)	11 (100.0)	11 (100.0)
Fractured teeth	54 (79.4)	14 (20.6)	68 (100.0)
Mobile teeth	5 (83.3)	1 (16.7)	6 (100.0)
Shocking sensation	9 (100.0)	0 (0.0)	9 (100.0)
Aetiology Falls	24 (55.8)	19 (44.2)	P= 0.405 43 (100.0)
Road traffic accident	32 (72.7)	12 (27.3/	44 (100.0)
Sporting/playground activities	6 (60.0)	4 (40.0)	10 (100.0)
Interpersonal violence	14 (66.7)	7 (33.3)	21 (100.0)
Domestic/Industrial accidents	17 (65.4)	9 (34.6)	26 (100.0)
Eating hard foods	14 (82.4)	3 (17.6)	17 (100.0)
Total	107 (66.5)	54 (33.5)	161 (100.0)

Table 4: Association between mean time elapsed between traumatic incidence and presentation and presence of crown discolouration

Crown discolouration	N	Mean time elapsed (days)
No	107	1376.14±2473.53
Yes	54	4827.81±3643.86

P=0.001

Discussion

Discoloured anterior teeth present considerable cosmetic impairment and especially among the young adult where appearance and acceptance mean a great deal. There is thus, an increase in the demand for the treatment of this condition. With increasing awareness among the population and newer materials available to the dentist, more patients will present for management of this aesthetically compromising problem. Crown discoloration is a sign of complications associated with traumatic dental injuries. It has been shown that complications such as pulp necrosis, root resorption and pulp canal obliteration are associated with crown discoloration [17]. The prevalence of discoloration observed in this study was 33.5% a value lower than that reported in a previous study on primary teeth which reported that 46% of traumatised teeth became discoloured two weeks after injury [18]. The prevalence in this study is much higher than that reported in literature [19-21]. It is, however, comparable to a previously reported study [21]. Previous literature reporting low incidences looked at specific causes of discoloration such as tetracycline stains; Koleoso et al., looked at discoloration generally in children and not restricted to those with traumatic dental injury [19, 21]. Ibiyemi et al. compared actual discoloration with self-perceived discoloration and reported a prevalence of 43%, which is comparable to that reported in the present study [22]. Our study reported a statistically significant relationship between the occupation of the participant and presenting with a discoloured tooth. This is probably because of increased awareness that comes with higher education as well as the ability to afford the cost of treatment.

Table 5: Predictors of the traumatised tooth becoming discoloured

*reference category: male, professionals, primary, single

Characteristics	B	P-value	Odds ratio	Confidence interval
Age	-0.047	0.21	0.954	0.89 - 1.03
Gender Female	0.972	0.03	2.642	1.10 - 6.34
Occupation Skilled workers	0.312	0.78	1.366	0.15 - 12.21
Semi-skilled workers	1.324	0.03	3.759	1.14 – 12.40
Unskilled workers	-21.253	0.999	0.000	0.000
Dependents	0.105	0.908	1.111	0.19 – 6.57
Education Secondary	-17.731	0.999	0.000	0.000
Tertiary	1.051	0.09	2.860	0.57 – 9.65
Marital status Married	-0.409	0.58	0.665	0.16 – 2.85
Time elapsed	-0.000	0.000	1.000	1.00 – 1.00
Constant	-1.181	0.43	0.307

The findings of this study show that the aetiology of the traumatic incident had no significant association with the presence or absence of a discoloured traumatised tooth however certain complaints were associated with tooth discoloration. This shows that tooth discoloration is an outward expression of an inner injury associated with complications arising from the traumatic incident and not a sign of an external force.

This study also revealed that the time elapsed between the traumatic incident and presentation for treatment was higher for those with discoloured teeth. This is probably because the colour changes manifest over time. A high proportion of study participants (42.2%) presented to the clinic on account of pain. This implies that most patients will still not present unless there is obvious discomfort. This supports a previous report that crown discoloration alone post-trauma may not be sufficient to cause persons to seek professional treatment [17]. Furthermore, it is possible that the awareness of the availability of treatment options for discoloured teeth may be low. As 81.9% of participants in a previous study claimed that they did not know that discoloration could be treated [23]. Thus, creating awareness that early presentation of traumatic dental injuries obviates development of negative outcomes is still very essential.

Our study also revealed that the higher the age of the participant, the less the likelihood of presenting with a discoloured traumatized tooth. This may be due to the fact that older adults present earlier before discoloration occurs due to the disfigurement as a result of a fractured tooth while the younger patient will need the consent and funds from parents before they can attend clinic. Therefore, the longer the time elapsed between the traumatic incident and presentation for treatment will cause the products of necrosis to cause discoloration of the tooth. The finding that more females than males presented with discoloration may be explained by a cultural and social factor in our environment where females tend to be more particular about their appearance and thus will present more often to the clinic on account of this. However, previous studies presented no gender predilection to discoloration [22, 23].

Conclusion

Crown discoloration is an aesthetically significant sequelae of traumatic dental injuries. Many patients will not present unless there is pain following a traumatic episode. Creating awareness about this discoloration following late presentation of trauma is needed. Gender, age and level of education are predictors of patients presenting with tooth discoloration.

h5>Conflicts of Interest

The authors have no conflicts of interest.

Article Info

Article Type

Research Article

Publication history

Received: Mon 01, Apr 2019
Accepted: Fri 03, May 2019
Published: Sat 29, Jun 2019

Copyright

© 2023 Joan Enabulele. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hosting by Science Repository.
DOI: 10.31487/j.DOBCR.2019.02.05

Author Info

Joan Enabulele Mohammed Bi

Corresponding Author

Joan Enabulele
Department of Restorative Dentistry, School of Dentistry, University of Benin, Benin City, Edo State, Nigeria

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