Introduction

Diagnosis of alveolar bony defects such as fenestration and dehiscence before orthodontic treatment is beneficial for orthodontists due to several reasons (Leung, Palomo, Griffith, & Hans, 2010). Studies have reported that the incidence of alveolar bone dehiscence and fenestration may cause a gingival recession, decrease bony support of teeth (Xu, Ren, Wang, Sun, & Fang, 2013; Zachrisson & Alnaes, 1974). An unrevealing and undiagnosed buccal alveolar bone defect leads to a greater potential for treatment relapse (Rothe et al., 2006). This leads to unaesthetic finishing of orthodontic treatment and can lead to tooth sensitivity (Samantha & Sridharan, 2016). Orthodontic treatment if not carried out properly, can lead to fenestration and dehiscence (Arvind & Jain, 2020).

Recognition of alveolar bony dehiscence and fenestration was not feasible with traditional 2-dimensional imaging (Krishnan, Pandian, & Kumar, 2015). With the advent of CBCT, it's now possible to view these defects three-dimensionally (Christopher, Marimuthu, C, Devadoss, & Kumar, 2018). Timock et al. reported that the precision and reliability of the buccal bone height, as well as thickness measurements from CBCT, are sustainable and appropriate (Jain, 2014; Timock et al., 2011; Vikram, 2017). Studies have examined the alveolar bony dehiscence using CBCT in patients with cleft lip and palate and those undergoing rapid maxillary expansion and in different malocclusions (Baysal et al., 2013; Buyuk, Ercan, Celikoglu, Sekerci, & Hatipoglu, 2016; Yagci et al., 2012).

However, there has not been significant literature examining alveolar bony defects in adults undergoing orthodontic treatment (Kamisetty, 2015; Viswanath, Ramamurthy, Dinesh, & Srinivas, 2015). It's essential that orthodontists should know the anatomical limits of tooth movement to make them aware of potential periodontal problems that could worsen during orthodontic treatment (Coşskun & Kaya, 2019; Hwei & Thomas, 2014). CBCT has shown to have high specificity and negative predictive value for dehiscence as well as fenestration but a low positive predictive value (Sun, Zhang, Shen, Wang, & Fang, 2015). Leung et al. reported that CBCT value has relatively high accuracy in diagnosing dehiscence and fenestration (Leung et al., 2010). Orthodontists using bony defects data as a precaution prior to treatment should be viewed as an exaggeration to the side of caution rather than giving misinformation. Given that CBCT users comprehend the extent of its accuracy, clinicians can still use the bony defect information within the boundaries of the overestimation limit (Murugesan & Jain, 2020).

The aim of this study was to determine the prevalence of posterior alveolar bony dehiscence and fenestration in adults undergoing orthodontic treatment.

Materials and Methodology

Study design

This was a retrospective study. 20 Adults subjects aged from 18 to 35 years old were chosen from DIAS and their CBCTs were retrieved. Only subjects in whom good quality CBCT were available

Inclusion criteria

• Class 1 malocclusion subjects with minimum crowding

• Subjects undergoing orthodontic treatment without any missing posterior teeth except for third molars

Exclusion criteria

• Obvious pathologies like cyst or tumor, bony pathologies and congenital defects

• Multiple carious lesions, restoration, abfraction, or abrasions.

• History of previous orthodontic treatment.

After applying the inclusion and exclusion criteria, 10 males and 10 females were included in the study.

Sampling method

To minimize sampling bias, simple random sampling was carried out. The investigator A.T. did not have access to the demographic information of the subjects CBCT DICOM files until the study had not been completed.

Bony defect measurement method

All CBCT images were observed and measured using dolphin imaging 11.8 premium software by the same investigator (A.T). The image was aligned using the FH line in such a way that the FH plane is parallel to the floor and the midsagittal plane was perpendicular to the FH plane. The posterior quadrant was observed in a multiplanar view with magnification up to 3 times. Once enlarged, the posterior segment was aligned anteroposteriorly on the axial view.

For the lesion to be identified as dehiscence, it had to be equal to or greater than 2mm in the vertical distance from CEJ. This was done in order to eliminate counting normal bone level as dehiscence, which is usually 1.5-2mm below the CEJ. There was no minimum requirement lesion size to be counted as fenestration. If any amount of bone was denuded on root surface but was not found to be continuous to the marginal bone, it was counted and measured as a fenestration.

Statistical Analysis

All statistical analysis was performed in SPSS. A Chi-square test was done to determine the association of the alveolar bony defects between males and females.

Results and Discussion

A tooth was counted as the one with bony defect when there was the presence of a defect on one side, either mesial or distal, or on both sides. Table 1 depicts the mean widths and standard deviation of bony defects. Table 2 depicts the association of extent of fenestrations and dehiscence in males and females. Figure 1 and Figure 2 represents the association of fenestration and dehiscence in males and females.

In Figure 1, The X-axis represents the width of the dehiscence and Y-axis represents gender. Pearson's chi-square value- 5.49, p value-0.019(<0.05) hence its statistically significant. In Figure 2 The X-axis represents the width of the fenestration and Y-axis represents gender. Pearson's chi-square value-1.818, p-value-0.178(>0.05) hence its not significant.

In the present study, all measurements were done on CBCTs patients requiring orthodontic treatment. On studying the extent of fenestration and dehiscence in males and females, it was reported that there was a significant association of more severity and extent of dehiscence in females than in males. There was no statistically significant association of extent of fenestration between males and females. With regard to patient selection, growing patients had not been included in the study because previous studies have reported that hormonal and functional changes associated with age influence cortical bone thickness (Papadopoulos, 2014; Usui, Uematsu, Kanegae, Morimoto, & Kurihara, 2007). In our study, CBCT was used since it is the imaging of choice in orthodontics nowadays since a 3-dimensional view of the entire dentition and craniofacial structures but due radiation concerns, CBCT should not routinely be considered in orthodontics (Meena & Kowsky, 2014).

Rupprecht et al. conducted a prevalence study of dehiscence and fenestration in modern American skulls and reported that African-American males and Caucasian females were significantly more likely to have dehiscences, while African-American females were significantly more likely to have fenestrations but this was a craniometric study whereas the present study involved CBCT (Leung et al., 2010). Similarly, Ana et al. reported that the percentage of teeth with considerable bone loss was higher in females, but was not significantly associated (Malčić et al., 2011). Choi et al. reported that adults in crossbite reported higher prevalence to total bony defects and dehiscence, but an association was not performed between males and females (Choi, Chaudhry, Parks, & Ahn, 2020).

The overall consensus in the available literature on this topic agrees with the findings of the present study. The limitation of this study was a small sample size. Since this was a retrospective study, the settings of the CBCT images could not be controlled. As dehiscence and fenestrations do not have a specific geometric shape, changing the orientation of the image can lead to a slight change in the measurements on measuring vertical diameter.

Future scope indicates that investigations should be carried out pre-and post-orthodontic treatment. Study larger sample size, more no. of teeth should be evaluated, and type of malocclusion should be taken into consideration.

Conclusion

Within the limitations of this study, it can be concluded that in females dehiscence defects were wider than males, but no gender association was seen for fenestration.

Funding Support

The authors declare that they have no funding support for this study.

Conflict of Interest

The authors declare that they have no conflict of interest for this study.