Prevalence and Association of Calcified Pulp Stones with Periodontitis: A Cone-Beam Computed Tomography Study in Saudi Arabian Population

ABSTRACT

This study aimed to identify the prevalence and association of periodontitis and pulp stone (PS) along with the clinical variables. This study assessed the cone-beam computed tomography (CBCT) records to identify the presence of PS and clinical periodontitis records were used to determine the stages of periodontitis. The Chi-square test was used to evaluate the relationship between study parameters. Logistic regression was used to determine the association between PS and periodontitis. A total of 228 CBCT records were conveniently selected for this study based on the inclusion and exclusion criteria. Cohen’s kappa analysis showed near to perfect scores for both examiners. The Chi-square test showed that CBCT records from the age range 41–50 years, male patients, and stage II of periodontitis prevalently showed pulp stones; however, there were no significant differences observed between the PS and clinical variables. However, gender, involvement of tooth, and stages of periodontitis showed significant distribution of the PS. Logistic regression showed that the stages of periodontitis showed no significant association with PS in patients with periodontitis. Moreover, multivariate odds ratio adjustment did not alter the outcome. Periodontitis is not associated with the presence of PS in the current population.

INTRODUCTION

The periodontium and pulp are two closely linked dental structures that could interact physiologically via different canals and pathologically through fissures and fractures.[1,2] In what way any pathology in the pulpal tissue affects the periodontium is explained in literature; however, the contrary scenario is debated and unknown.[3] Many radiographical and histological studies attempt to identify the histological alteration of the pulp when periodontal diseases are present; however, the outcomes were inconsistent including degeneration of pulp, chronic inflammation, and necrosis of pulp.[4,5,6] Calcification of pulp could be manifested by the degeneration of the pulp tissue.

A distinct calcified mass usually identified in the pulp of the primary or permanent teeth is known as a denticle or pulp stone (PS).[7,8] PS could be found in single or multiple teeth in healthy or diseased teeth from tiny particles to immense masses concealed in the whole pulp chamber.[9,10] The exact etiology of the PS is not completely comprehended; nevertheless, different factors such as deep restoration, dental caries, inflammation, aging, orthodontic movement of the teeth, genetic disorder, interruption in pulp circulation, and interaction between pulp and epithelium might play important roles in forming PS.[11] Moreover, hypercalcemia is also an influencing aspect for the formation of PS and it mostly forms while irritated pulp tissue attempts to repair itself.[12]

PS is most commonly observed in the first molars followed by second molars in both arches and least commonly identified in anterior teeth.[13,14] Different studies showed different prevalence rates of PS ranging from 8 to 90%.[6,15] Radiographic studies on PS tend to exhibit a lower prevalence rate compared to histological studies as radiographs are unable to detect calcified masses less than 200 μm.[9,13,16] However, the usage of cone-beam computed tomography (CBCT) has increased in recent years due to the three-dimensional (3D) images, which offer more precise diagnoses in dental treatments. Moreover, previous studies on the detection of PS showed CBCT outweighs the outcome of two-dimensional (2D) findings.[17,18]

In addition, the prevalence of PS was assessed previously in different populations in the different studies which exhibited various outcomes.[19,20,21,22,23,24,25] These variations in prevalence between populations could be the result of ethnic and geographical disparities. As per the literature search, no study has compared the prevalence of PS in Saudi populations related to the stages of periodontitis. Hence, this study aimed to evaluate the presence of PS using CBCT images and to correlate their prevalence with age, gender, and different stages of periodontitis. The null hypothesis of the present study was that there would be no significant difference in PS formation between different stages of periodontitis.

MATERIALS AND METHODS

This retrospective radiographic study was conducted in the College of Dentistry, Prince Sattam Bin Abdulaziz University. The standing committee of bioethics research (SCBR) of Prince Sattam bin Abdulaziz University approved this study protocol (SCBR-111/2023). Moreover, the study was conducted according to the guidelines of the Declaration of Helsinki.

Complete periodontal records and CBCT radiographs of patients with periodontitis who were above 18 years old and whose roots of the permanent teeth were completely developed were included in this study. On the other hand, incomplete periodontal records, teeth with endodontic treatment, radiographs with crowns and bridges that did not allow a clear view of the pulp chamber, and radiographs with artifacts were excluded from the study.

Clinical periodontitis records such as pocket depth, clinical attachment level, and bleeding on probing of the patients were used to measure the stages of periodontitis according to the new classification of periodontal disease.[26] CBCT scans were selected as a convenient sampling technique from the archive of the Department of Radiology, College of Dentistry, Prince Sattam Bin Abdulaziz University, were analyzed for identifying the pulp stone. The presence of pulp stones in the pulp chamber and root canals were analyzed in the sagittal, axial, and coronal planes of the CBCT images [Figure 1].

Figure 1.

CBCT images of pulp stones; (a) Axial CBCT section of mandibular first molar with pulp stones. (b) Axial CBCT section of maxillary molars with pulp stones. (c) Sagittal CBCT section of mandibular second molar showing pulp stones. (d) Sagittal CBCT section of maxillary 1^st molar with pulp stones

All the CBCT images were obtained using Carestream CS 9300 (Carestream Dent LLC, Atlanta, G, USA) with the following parameters: a TFT sensor with a continuous mode scan time of 12-28s, field of view (FOV) of 10 × 10 cm, and voxel size of 180-300μm. Analyzing the images was done using CS 3D imaging software (Carestream Dent LLC, Atlanta, G, USA). The images were evaluated by two expert radiologists with more than five years of experience. A total of 20% CBCT images were assessed two times in two-week intervals by both radiologists for the reliability of the measurement.[27]

Statistical analysis

All statistical analyses were performed using the statistical package for Social Science (SPSS) version 27 (IBM, Armonk, USA). Intra-examiner and inter-examiner reliability was conducted by Cohen’s Kappa statistics. Descriptive statistics were used for the frequency distribution of all the responses. The Chi-square test was used to evaluate the relationship between study parameters. Logistic regression was used to determine the association between pulp stone and periodontitis. The statistical significance level was set at 5%.

RESULTS

A total of 228 CBCT records were conveniently selected for this study based on the inclusion and exclusion criteria. Two independent radiologists assess all the CBCT images, and 20% of CBCT images were assessed two times in two-week intervals for reliability. Cohen’s kappa analysis showed near to perfect scores for both examiners. CBCT records consisted of 135 males and 93 females with an age range from 19 to 60 years (41.88 ± 11.05) old. The age range of the patients was divided into 10-year intervals. The classification of periodontitis was assessed based on the periodontal charting of the patients. All the distributions of the variables are presented in Table 1. It showed that 17.50% of the total CBCT records exhibited the presence of pulp stones.

Table 1.

Frequency distribution of the variables

Variables	Frequency	Percentage
Gender
Male	135	59.20
Female	93	40.80
Age range
≤20	4	1.80
21-30	44	19.30
31-40	55	24.10
41-50	62	27.20
51-60	63	27.60
Stages of Periodontitis
Stage I	69	30.30
Stage II	93	40.80
Stage III	48	21.10
Stage IV	18	7.90
Pulp stone
Present	40	17.50
Absent	188	82.50

The Chi-square test showed that CBCT records from the age range 41–50 years, male patients, and stage II of periodontitis prevalently showed pulp stones; however, there were no significant differences observed between the pulp stones and clinical variables of the selected CBCT records [Table 2]. Moreover, no significant relation was observed between gender and other clinical variables. The distribution of the gender and clinical variables is shown in Figure 2.

Table 2.

The frequency between pulp stone and clinical variables

Variables	Pulp stone (%)		P
	Present	Absent
Age range
≤20	0 (0.00)	4 (1.80)	0.558
21-30	7 (3.10)	37 (16.20)
31-40	7 (3.10)	48 (21.10)
41-50	14 (6.10)	48 (21.10)
51-60	12 (5.30)	51 (22.40)
Gender
Male	27 (11.80)	108 (47.40)	0.289
Female	13 (5.70)	80 (35.10)
Stages of Periodontitis
Stage I	6 (2.60)	63 (27.60)	0.127
Stage II	20 (8.80)	73 (32.00)
Stage III	11 (4.80)	37 (16.20)
Stage IV	3 (1.30)	13 (6.60)

% = Percentage, P=P

Figure 2.

Distribution of clinical variables between (a) gender and stages of periodontitis, (b) gender and age ranges, and (c) gender and presence of pulp stones

Table 3 showed the distribution of the pulp stones and it exhibited that 67.50% of the male patients consist of pulp stones compared to their counterparts. The CBCT records of patients over 40 years old exhibited more pulp stones than those who were <40 years old. The majority of the pulp stones were observed in the first molar, mandible, and left side of the arch. Moreover, 50% of the PS identified in patients who were classified as stage II of periodontitis. One-sample Chi-square test showed that there were significant differences in gender, teeth involved with PS, and the stages of periodontitis.

Table 3.

Frequency of pulp stone distribution

Variables	Frequency	Percentage	P
Age range
21-30	7	17.50	0.145
31-40	6	15.00
41-50	15	37.50
51-60	12	30.00
Gender
Male	27	67.50	0.040*
Female	13	32.50
Arch
Maxilla	14	35.00	0.150
Mandible	18	45.00
Both	8	20.00
Sides
Right	13	32.50	0.218
Left	18	45.00
Both	09	22.50
Tooth involved
1st molar	19	47.50	0.0001*
2nd molar	3	7.50
Both molars	9	22.50
Premolars	3	7.50
Premolars and 1st molar	5	12.50
Premolars and both molars	1	2.50
Stages of Periodontitis
Stage I	6	15.00	0.001*
Stage II	20	50.00
Stage III	11	27.50
Stage IV	3	7.50

P=P, *significant difference (P<0.05)

Logistic regression was used to determine the association between pulp stone and the stages of periodontitis. The statistical association was expressed by univariate odds ratio (OR) and multivariate OR adjusted for age, age range, and gender. The stages of periodontitis showed no significant association with pulp stones in patients with periodontitis [Table 4]. Moreover, multivariate OR adjustment did not alter the outcome; therefore, the background of the patient’s characteristics did not influence the presence of pulp stone.

Table 4.

Association of pulp stone and stages of periodontitis

Clinical variables	Univariate				Multivariate
	OR	95% CI		P	OR	95% CI		P
		Lower	Upper			Lower	Upper
Stage I	-	-	-	0.231	-	-	-	0.412
Stages II	2.827	0.561	14.242	0.208	1.342	0.162	11.132	0.784
Stages III	0.907	0.227	3.624	0.890	0.512	0.097	2.707	0.431
Stages IV	0.808	0.184	3.552	0.777	0.646	0.140	2.972	0.574

OR=Odds ratio, CI=Confidence interval, % = Percentage, P=P

DISCUSSION

This study aimed to evaluate the prevalence of PS using CBCT images and to correlate with age, gender, and different stages of periodontitis. A total of 228 CBCT records were measured to identify the PS in the current study. There were many studies conducted in the past for PS identification using radiographic records.[19-21,23-25,28,29] However, most of the studies used traditional 2D radiographs such as panoramic, periapical, and bitewing. The diameter of the PS needs to be a minimum of 200 μm to detect in the 2D radiographs. Therefore, the definite prevalence rate of PS might alter in 2D radiographic studies. Few studies used CBCT as the measurement tool for the PS similar to the current study.[14,15,22,30,31,32,33]

In general, the aforementioned studies that used CBCT images showed higher percentages of PS compared to the studies, which used 2D radiographs. Tassoker et al.[8] compared the CBCT and panoramic radiographs to detect pulp stones and found a significant difference between 2D and 3D radiographs in detecting PS and recommended CBCT images for assessing PS.

Even though the current study used CBCT images for detecting PS, only 17.50% of radiographs identify PS. The presence of pulp stone is different in different ethnic backgrounds;[34,35] therefore, the prevalence rate should vary. In the Turkish population, the prevalence rate varies from 12 to 63.6%.[16,34,36,37] A similar range was also identified in the Indian population where different studies ranged the prevalence of PS from 14.4 to 58%.[19,25,38,39,40] The current study was conducted on the population of Saudi Arabia. Previous studies in Saudi Arabia showed 14.7%,[24] 28%,[41] and 50.2%,[33] the prevalence rate of pulp stones by Patil et al.[33] conducted the study on adolescent patients in Saudi Arabia; however, other aforementioned studies in Saudi Arabia along with the current study included the records of adult patients only similar with the current study. Therefore, age might play an imperative role in the higher percentage of PS.

The current study included CBCT records from 19 to 60 years of age and divided the age range into 10-year intervals. The outcome of this study showed that the majority of the CBCT records were from the age range of 51 to 60 years and the PS prevalently observed in the age range of 41 to 50 years. However, the age range did not exhibit any significant relation with the PS. This outcome supports the previous studies where the age range did not associate with the presence of PS.[8,15,29,32] However, alternate outcomes were also observed where age range was associated with PS.[7,20,22,24] The studies that showed significant association usually found more PS in the lower age range, unlike the current study.

Among all the included CBCT images in this study, 59.40% were male and gender showed no significant association with the presence of PS. This result supports the previous studies where gender did not play any significant role in the presence of PS.[8,19,21,24,33] On the contrary, a few studies reported that females were more prevalent in PS and showed significant association in the presence of PS.[15,20,22,23,29] This different outcome might be due to the different ethnic backgrounds and inclusion of more female patients than their counterparts. Another study on the Saudi Arabian population showed a similar outcome to the current study where male patients were more prevalently included and identified more PS in male patients.[33] Therefore, future studies with equal distribution of gender might provide more precise outcomes. However, PS was found significantly prevalent in male CBCT records in this study, which is in line with the study outcome by Chen et al.[7]

In this study, most of the PS was found in the mandibular arch. The majority of the previous study showed prevalence in maxillary arch regardless of the significant association.[7,20,22-24,32] Only two studies showed the prevalent number of PS in the mandibular arch without any significant association in line with the current study.[8,33] Outcome of one of the studies between the aforementioned two studies was conducted in the Saudi population similar to this study. Moreover, the left side of the arch exhibited more PS in this study without any significant association. The majority of the previous studies showed the prevalent number of PS in the left side alike to the current study.[8,19,22,24,33] Only a few studies showed a greater number of the PS on the right side of the arch.[7,20,23] However, none of the studies showed any significant association with the PS regarding the side of the arch, which is also supporting the current outcome.

In this study, it showed that PS was observed more prevalently in the first molars than in the other posterior teeth, which is supporting most of the previous studies on PS.[15,19,20,22-25,32,33] However, Tassoker et al.[8] and Ravichandran et al.[21] reported more PS found in mandibular incisors and Chen et al.[7] exhibited more PS on canines. These differences might be due to the total number of teeth assessed and the population variation of the studies. Moreover, there were significant differences observed among all the teeth assessed with PS, which also supports the outcome of previous studies.[15,22-24,32,33] Hence, it could be assumed that molar teeth are more susceptible to form PS that might be due to the larger pulpal orifice and multiple roots present in the molar teeth.

This study also assessed the association of PS with the different stages of periodontitis, which showed that 40.80% of total records were identified as stage II of periodontitis following stage I, stage III, and stage IV. As per the literature search, only one previous study was conducted on PS and different periodontitis and reported a similar outcome as the current study.[29] However, that study was conducted on the Moroccan population and no other study was piloted in the Saudi population. It was tabulated in the current study that 8.80% of the total CBCT records showed stage II periodontitis, whereas 12.60% of total samples showed stage II periodontitis by Nissrin et al.[29] Stages of periodontitis were not significantly associated with the presence of PS in the current population as well as the study by Nissrin et al.[29] However, the current study showed that 50% of the CBCT records within the PS consist of stage II of periodontitis and are significantly prevalent compared to the other stages of periodontitis. Therefore, it might assume that stages of periodontitis play an important role in the formation of PS. However, not many studies were conducted on this topic and more future studies are required to be conducted to come to a precise conclusion.

The current study possesses some limitations. All the CBCT records were included in this study based on the conventional sampling technique; however, appropriate sample size calculation could have provided a precise outcome. Other systemic disease was not considered in this study, which could expand the current outcome. Moreover, this study only included records for adult patients; nevertheless, the inclusion of adolescent patients could provide more insight and comparison to the current study. In addition, the current study did not distinct the presence of PS in pulpal orifice or in the root area. Comparison of the presence of the PS in pulpal sites could enhance the outcome of this study. Therefore, more future studies were recommended to minimize all these limitations.

CONCLUSIONS

In conclusion, even though CBCT records from the age range 41–50 years, male patients and stage II periodontitis prevalently showed pulp stones; however, there were no significant associations observed in the current population.

Author contributions

Conceptualization, methodology, validation, formal analysis, investigation, resources, data curation, writing—original draft preparation, writing—review and editing, visualization, supervision, project administration, funding acquisition: A.S.A.

Institutional review board statement

The study was conducted in accordance with the Declaration of Helsinki and approved by the standing committee of bioethics research (SCBR) of Prince Sattam bin Abdulaziz University approved this study protocol (SCBR-111/2023).

Informed consent statement

Informed consent was waived owing to the retrospective nature of the study.

Data availability statement

The data presented in this study are available upon request from the corresponding author.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.