Evaluating Factors Influencing Periodontal Bone Loss Using Cone Beam Computed Tomography: A Retrospective Study

Introduction

Periodontal diseases are inflammatory conditions affecting the gingiva and the dental supporting tissues [1,2]. Inflammation and bacteremia resulting from periodontal diseases directly or indirectly affect the systemic health of patients [3]. Therefore, periodontal diseases are also recognized as a global public health problem that affects the overall quality of life and health of individuals [4].

The inflammatory response initiated in the gingiva due to host–microorganism interaction spreads to the supporting tissues of the teeth, leading to destruction of periodontal ligament fibers and alveolar bone loss [5,6].

The changes in the alveolar bone are crucial, as they often result in tooth loss. Alveolar bone levels and bone mineral density are regulated by systemic and local factors. This maintains the balance between bone formation and destruction. If this balance shifts toward destruction, bone height and density decrease [7].

Due to the specific nature of periodontal diseases, bone destruction is not uniform across all teeth and is variable. Studies of regions with alveolar bone loss have shown that tooth type, bone level, and the individual’s age are key determinants [8,9]. Elucidating how destructive periodontal diseases progress across different age groups, teeth, and tooth surfaces provides valuable insights for prevention and treatment planning, as well as for tailoring specific approaches for regions with greater attachment loss [10–13].

Diagnosis of periodontal diseases is mainly based on clinical signs and symptoms. However, when bone loss is involved, radiographs play a crucial role as an adjunct to clinical examination [14]. Digital and traditional radiographs are the primary diagnostic tools for these conditions [15,16]. Although these methods offer advantages such as low radiation dose and cost effectiveness, they also present substantial limitations, including magnification, distortion, and superimposition. Consequently, 2-dimensional imaging methods are insufficient for tracking changes in alveolar bone over time or for determining the architecture of bone defects [17–19].

Studies have demonstrated that cone beam computed tomography (CBCT) technology provides a novel perspective in the evaluation of periodontal diseases [20–22]. CBCT has been reported to exhibit high diagnostic accuracy in determining the extent of alveolar bone loss [9,23].

In this study, we aimed to measure periodontal bone loss in individuals of various age groups, using CBCT, and to investigate the distribution of these values by age, sex, jaw type (mandible or maxilla), tooth type, and tooth surface (mesial or distal). Moreover, we investigated whether a relationship exists between tooth surface width, measuring buccolingual (BL) and mesiodistal (MD) widths at the cemento-enamel junction (CEJ), and bone loss in areas with advanced bone destruction. Although there are various radiological studies in the literature evaluating the relationship between periodontal bone loss and factors such as age, sex, and tooth type, studies assessing this relationship using CBCT are quite scarce. To the best of our knowledge, no study has evaluated the relationship between the cervical width of the tooth surface and periodontal bone loss.

This study, which was performed on a large number of teeth with CBCT, is very important in terms of accurate diagnosis of periodontal diseases, determination of prognosis, and region-specific treatment planning. Therefore, we believe that our study is unique and will contribute substantially to the literature.

Material and Methods

STATISTICAL ANALYSIS:

Data obtained from the examined CBCT images were analyzed using a licensed IBM SPSS 21 software package. Normal distribution of variables was assessed using the Shapiro-Wilk and/or Kolmogorov-Smirnov tests, depending on the sample size. A significance level of 0.05 was applied; variables were considered to not follow a normal distribution if P was <0.05 and to follow a normal distribution if P was >0.05.

If the variables did not follow a normal distribution, the Mann-Whitney U test was used for comparisons between 2 groups and to compare the severity of alveolar bone level (mm) between men and women. The Kruskal-Wallis H test was used for comparisons among more than 2 groups (Dunn test). It was used to compare the severity of alveolar bone level (mm) between the examined sites, maxillary and mandibular teeth. Furthermore, the Bonferroni test was used for multiple comparison correction. Pearson chi-square analysis was used for nominal variables to examine relationships between groups.

The Spearman correlation coefficient was applied to evaluate relationships between non-normally distributed variables. Results were interpreted with a significance level of 0.05, where P of <0.05 indicated a significant difference and P of >0.05 indicated no significant difference.

Results

A total of 1000 CBCT images were examined, of which 200 CBCT images meeting the desired criteria were included in the study. Patients aged between 19 and 66 years were divided into groups with equal numbers of individuals in each age group and sex. Regarding tooth type, 23.9% were molars, 28.59% were premolars, 15.89% were canines, and 31.63% were incisors. The total number of observed teeth was 4929, with the highest number (1336 teeth) found in the 19–29 age group, accounting for 27.1% of all teeth. Among individuals aged 50 years and above, the number of observed teeth was 1115.

In the present study, the average periodontal bone loss was observed to be 0.21 mm in the 19–29 age group, 0.64 mm in the 30–39 age group, 1.51 mm in the 40–49 age group, and 1.75 mm in the ≥50 age group. The mean bone loss value significantly increased with age (P<0.05; Table 1).

A statistically significant difference was observed between sexes in terms of mean bone loss values. The mean bone loss was significantly lower in women than in men (P<0.05). The mean value was 0.82 mm in women and 1.15 mm in men (Table 2).

There was no statistically significant difference between jaw groups in terms of mesial bone loss values (P>0.05). However, distal surface bone loss in the mandible was significantly lower than that in the maxilla. In other words, bone loss was greater in the distal regions of the maxilla than in the mandible (P<0.05; Table 3).

A statistically significant difference was observed in terms of mesial bone loss values among different tooth types (P<0.05). Mesial bone loss in mandibular premolars, maxillary premolars, and maxillary incisors was significantly lower than that of mandibular incisors and maxillary molars. Moreover, the mesial bone loss in mandibular molars, mandibular canines, and maxillary canines was significantly lower than that of maxillary molars. Among the teeth with mesial bone loss, mandibular molars and mandibular incisors showed the highest levels of bone loss after maxillary molars (Table 4).

A statistically significant difference was also observed in distal bone loss values among tooth types (P<0.05). Distal bone loss in all tooth groups was significantly lower than that of maxillary molars. Following the maxillary molars, the mandibular incisors showed the highest distal bone loss (Table 4).

When mean bone loss values were evaluated, a statistically significant difference was observed among tooth types (P<0.05). The mean bone loss values for all tooth groups were significantly lower than that of maxillary molars. Following the maxillary molars and mandibular incisors, the mandibular molars exhibited the highest mean bone loss (Table 4).

No statistically significant relationship was observed between the mean bone loss values and MD and BL width in mandibular molars and maxillary molars (P>0.05). However, a statistically significant relationship was found between mean bone loss values and MD width in mandibular premolars and mandibular incisors (P<0.05). This relationship was weak and inverse (mandibular premolar r=−0.189; mandibular incisors r=−0.250). As the MD width of mandibular premolars and mandibular incisors decreased, the mean bone loss values increased (Table 5). Similarly, a statistically significant relationship was observed between the BL width and the mean bone loss values in mandibular premolars and mandibular incisors (P<0.05). This relationship was weak and inverse (mandibular premolar r=−0.166; mandibular incisors r=−0.170). As the BL width of mandibular premolars and mandibular incisors decreased, the mean bone loss values increased (Table 5).

In maxillary premolar teeth, a statistically significant inverse and weak relationship was found between the mean bone loss values and BL width values (r=−0.193, P<0.05). As the BL width of maxillary premolars decreased, the mean bone loss values increased. However, no significant relationship was found between MD width and bone loss (Table 5).

In mandibular canine teeth, a statistically significant relationship was found between the mean bone loss values and MD width values (P<0.05). This relationship was weak and inverse (r=−0.164). As the MD width of mandibular canines decreased, the average bone loss values increased. No statistically significant relationship was found between the mean bone loss values and BL width values in mandibular canines (P>0.05; Table 5).

Discussion

AGE AND SEX DIFFERENCES:

In a study conducted by Albandar between 1988 and 1994 to investigate the prevalence of periodontal disease in the United States, the prevalence of attachment loss was reported as 8% in the 30–39 age group and 35.3% in the 60–69 age group [31]. Eke et al conducted a study between 2009 and 2010 with large patient groups to assess the prevalence of periodontitis in adults over 30 years of age. They observed that the risk and prevalence of periodontal disease were higher in older age groups than in younger individuals. They also reported a higher prevalence of periodontitis in men than in women [32]. Cross-sectional epidemiological studies have shown that the prevalence of periodontitis increases with increasing age [33]. Furthermore, it has been reported that periodontal status among women is better than that of men in all age groups [31,34].

In the present study, the mean bone loss observed was 0.21 mm in the 19–29 age group, 0.64 mm in the 30–39 age group, 1.51 mm in the 40–49 age group, and 1.75 mm in the ≥50 age group. Periodontal bone loss increased with increasing age. The mean loss observed in women was 0.82 mm, compared with 1.15 mm in men. Mean bone loss was higher in women.

These results are consistent with those of studies evaluating the risk factors and prevalence of periodontal diseases [32,33]. The reasons for these sex differences are thought to be related more to poorer oral hygiene and less dental-visit behavior among men than to any genetic factor. In addition, smoking is a major risk factor for periodontal disease, and the global prevalence of smoking is greater in men than in women. Therefore, sex-related differences in smoking behavior should be considered when comparing estimates of periodontitis prevalence between men and women. Recent evidence also supports the importance of sexual dimorphism in the pathophysiology of plaque-induced periodontal disease.

VARIATIONS BY TEETH TYPES:

The extent of periodontal disease affecting different regions of the dentition, different teeth, and different surfaces of the same tooth varies and shows changes [11,12].

In a 17-year longitudinal study conducted by Airila-Månsson et al in 2005, the teeth most significantly affected by periodontitis were maxillary molars, whereas mandibular incisors were another group most affected [35]. In a study by Müller and Ulbrich, bone loss was found to be more pronounced on distal surfaces than mesial surfaces in younger age groups, specifically in the 19–29 and 30–39 age groups. Bone loss was greater in the maxilla than in the mandible, with molar teeth showing the highest loss [36].

Salonen et al observed that the most bone loss occurred in maxillary molar and mandibular incisor teeth, with the least bone loss in maxillary canine teeth. Bone loss was more pronounced in the maxilla than in the mandible. Individually, statistically significant differences were observed between mesial and distal surfaces, with more bone loss occurring on distal than on mesial surfaces [37].

In the present study, the highest average bone loss values were observed in the maxillary molar teeth. These were followed by mandibular incisor and molar teeth, respectively. The average bone loss for maxillary molar teeth was 1.24 mm, making them the teeth with the most periodontal bone loss. The second most bone loss was observed in mandibular incisors, with a bone loss of 1.11 mm. These findings are consistent with studies reporting a higher prevalence of periodontal bone destruction in maxillary molar and incisor teeth than in other tooth types, and they support these studies [35–38]. In the present study, no significant difference was observed between the jaws regarding mesial surfaces, and the average bone loss on distal surfaces was higher in the maxilla than in the mandible. This supports studies that also report the highest bone loss in the maxilla and on distal surfaces [35–38]. The first upper molars contain a larger number of roots, furcation, and shorter root on the distal surface. These anatomical tooth characteristics can facilitate the retention of plaque and impair plaque removal and access of instruments to distal sites. The areas in the mouth where plaque and calculus accumulate the most are usually the upper molars and lower incisors. Accumulation of calculus and dental plaque is a major risk factor for periodontal diseases.

VARIATIONS BY TOOTH SURFACE WIDTH:

In the present study, the relationship between bone loss and BL and MD width in the CEJ of different tooth types was also evaluated. In our literature review, we did not find any studies examining the effect of root surface area or tooth surface width on periodontal bone loss. By measuring the MD and BL width in the cervical region of the tooth using CBCT, the present study provides unique insights in evaluating the effect of this width on periodontal bone loss. The starting point of our study was previous research on root surface area and attachment level [39]. Based on these studies, we evaluated whether there is any relationship between BL and MD width at the CEJ and bone loss.

No significant correlation was found between MD and BL widths of the maxillary and mandibular molars and bone loss values measured in the proximal regions. However, statistically significant relationships were found between the MD and BL widths and the average bone loss values in the mandibular premolar and incisor teeth. As the MD and BL widths of these teeth decreased, the average bone loss increased. The lower incisors and premolars are the smallest teeth in the mouth and have the shortest roots. These teeth present deeper root concavities. When a vertical force is applied to a single-rooted tooth, it is seen that the tooth is embedded into the alveolus parallel to its long axis. In contrast, single-rooted teeth have a mechanical disadvantage of not being sufficiently resistant to horizontal forces. Such a force tries to move the tooth in the alveolus according to the direction of the force. The decrease in MD and BL widths in the cervical region in single-rooted teeth with smaller dimensions and the increase in the rate of bone loss may be related to root morphology and the distribution of chewing forces.

In the maxillary premolar and incisor teeth, there was a significant relationship between BL width and the average bone loss. As the BL width of these teeth decreased, the average bone loss values increased. However, no significant relationship was found between MD width and bone loss.

In the mandibular canine teeth, a significant relationship was observed between MD width and bone loss, but no relationship was found with BL width. As the MD width of the mandibular canine teeth decreased, the average bone loss values increased. In other tooth groups, no significant relationship was observed between MD and BL widths and periodontal bone loss. In a study conducted by Despeignes, it was noted that one of the most important factors influencing tooth stability is the size of the root surface area supported by bone [40]. It was stated that a decrease in the root surface area means fewer periodontal ligament fibers attaching between the cementum and alveolar bone, and a smaller attachment area. According to the study, the same amount of bone loss does not produce the same result for all tooth types. The length, morphology, and surface area of the tooth root affect the outcomes [40]. There is a strong correlation between periodontal bone loss and the severity of inflammation. Therefore, recent studies have suggested that measuring the periodontal surface area affected by inflammation can be useful in periodontal diseases [41]. However, in chronic periodontitis, inflammation extends beyond the root surface to the surrounding tissues, and it has been reported that the amount of inflammation cannot be evaluated solely by the root surface area [42]. Therefore, an increase in tooth surface width alone does not allow an inference to be made regarding increased inflammatory burden [42].

Mowry et al reported that a decrease in root surface area is associated with periodontal attachment loss, but this relationship is not directly proportional [43]. In the present study, bone loss increased as MD width and BL width decreased in teeth with smaller dimensions, such as mandibular incisors and mandibular premolars. However, for larger teeth, such as molars, no relationship was found between MD and BL widths and bone loss. These results are consistent with the studies conducted by Despeignes and Mowry et al.

The present study was conducted retrospectively, and the lack of clinical examination and medical history data, such as oral hygiene status, presence of systemic diseases, and smoking habits, are important limitations. However, in the present study, bone loss in the mesial and distal regions of each tooth, along with the MD and BL widths of each tooth in the cervical region, was measured using CBCT in a total of 4929 teeth across 8 different tooth types. The sample size of our study was sufficient, and the power analysis yielded a power level of 99%. The findings of the present study provide valuable information regarding the prevalence of bone loss in the population, changes in bone loss across tooth types, differences by sex, and the relationship between the cervical width of the tooth and periodontal bone loss.

Conclusions

Within the scope of these findings and the limitations of our study, it can be stated that periodontal bone loss is influenced not only by age, sex, and tooth type but also by the width of the tooth surface in the cervical region. Alveolar bone loss increased significantly with increasing age. The highest level of bone loss was observed on the distal surface and in the upper molars. Alveolar bone level increased as MD and BL width values of the lower premolars and lower incisors decreased. In the upper premolars and upper incisors, alveolar bone loss increased as BL width values decreased.

Considering this information in periodontal treatments, implementing region-specific treatment planning, and providing additional information to patients on this matter may contribute to the success of periodontal therapies. However, this study was conducted retrospectively using CBCT images, and further studies supported by clinical observations are needed to validate these findings.

Data Availability Statement

Data supporting the reported results are available from the corresponding author upon reasonable request.