Prosthetic Requirement for Laser Crown Lengthening in Chennai Population - A Retrospective Study

Keywords

Endodontic Treatment; Laser Crown Lengthening; Orthodontic Treatment; Prosthodontic Treatment.

Introduction

Numerous clinical situations are encountered by dentists everyday. Few of them are subgingival caries, fractured teeth. Crown lengthening is done to expose sufficient tooth structure to facilitate proper restoration as well as enhance the aesthetic appearance [1]. Various indications for crown lengthening are subgingival caries exposure, access to subgingival root paerforations, correction of gummy smile, exposure of fractured teeth. Most important factor to be considered during crown lengthening is biological width. It is the amount of soft tissue attached to the tooth above the alveolar crest. Biological width should be at the least 2.04 mm. 0.97 mm of epithelial attachment and 1.07 mm of connective tissue attachment with 1 mm of sulcus depth [2].

Based on clinical scenario, procedure is categorised into aesthetic and functional. In some situations crown lengthening is done for both cases. Reasons to do crown lengthening in endodontic or prosthodontic treated patients is that the extension of restorative margin below the biologic width causes gingival inflammation and resorption of crestal alveolar bone [3]. Hence crown lengthening in these patients are done to maintain the health of the periodontium [4]. Aesthetic crown lengthening is done to correct the gingival asymmetry and correction of clinically short crowns which is caused due to altered passive eruption leading to gummy smile [5]. For prosthetic requirements, crown lengthening is done if there is insufficient clinical crown, difficult in placement of finish line [6].

Crown lengthening procedures are accompanied by uses of scalpel or laser [7]. Laser is mostly accepted both by the dentist and patients due to its various advantages. The bloodless nature of laser therapy provides good visualisation for clinicians [8]. Compared to scalpel, lasers can easily reshape oral soft tissue [9]. Lasers produce less wound contraction and minimal scarring [10]. The crown lengthening in the aesthetic zone has progressively increased due to the smile enhancement therapy. It is essential for dentists to understand the diagnostic criteria , treatment planning and biological parameters as well as surgical and restorative protocols to enhance predictable outcomes in the aesthetic zone.

Many clinical studies, in vitro and in vivo studies have been done by our team in saveetha dental college in the department of prosthodontics over the past 5 years [11-25]. Now we are focusing on epidemiological studies. Hence the present study was done to evaluate the prosthetic requirement for laser crown lengthening in the Chennai population.

Materials and Methods

The study was in a University setting. Study includes patients who underwent crown lengthening in the anterior region (aesthetic zone). Sample size is 74. The study was a retrospective unicentric observational study. Ethical approval from university ethics committee. Data was collected from DIAS where the dental and medical history of the patients were recorded. The data tabulation done in excel sheet and transferred to SPSS for data analysis. Chisquare test was done.

Study design

This is a retrospective study conducted in a private dental institution. The patient case records were reviewed for the necessary information by a trained examiner. The advantage of conducting the study in an institutional set up provides easy access to patient records. Among patients who have visited the dental clinic of the institution, the case records of 74 patients were reviewed. A wide age range is selected for the study. The institutional ethical committee provided approval for the study (SDC/SIHEC/2020/DIASDATA/ 0618-0319).

Inclusion criteria

1. Patients who had undergone laser crown lengthening in anterior and premolar region
2. Patients from < 30 years to >51 years of age

Exclusion criteria

1. Incomplete patient data 2. Duplicate patient data 3. Laser crown lengthening in molars

Sampling

A total of 74 case records of patients who underwent laser crown lengthening were reviewed to find out the reason for crown lengthening. Convenient sampling method was used to select the patients for the study. The data obtained from the case records were cross verified with photographs.

Data collection

All the data after thorough checking for duplicates, incomplete entries and cross verification with photographs were entered in Microsoft excel spread sheet in order to organise the data. The variables obtained from the data included age, gender, arch, and reason for crown lengthening. Here the age, gender are the independent variables and, the reason for crown lengthening is the dependent variable.

Statistics

The statistical analysis of the obtained data was performed by the SPSS software version 23.0. The data from the excel spreadsheet was transferred to SPSS software for analysis. Chi square tests were employed in order to find the association between different variables. The p value less than 5% was considered statistically significant. The final results are presented in the form of graphs for further interpretation and discussion.

Results and Discussion

Numerous conditions require crown lengthening such as unaesthetic gingival heights , inadequate crown length, subgingival caries, crown fracture [26]. Crown lengthening can be done if the sulcus depth is more than 4mm [27].

Total of 74 patients were included in this study. All these patients had undergone laser crown lengthening in the anterior or premolar region due to either endodontic, prosthodontic or orthodontic reason. Out of 74 patients 46.25% were males and 55.75 % were females. The mean of the males who underwent laser crown lengthening was 29.35 ± 9.7 and the mean of females who underwent laser crown lengthening was 33.73 ± 13.

The distribution of arch and reason for crown lengthening was studied of which, 40.54% had undergone crown lengthening in the upper arch due to endodontic treatment, 20.27% due to orthodontic treatment and 12.16% due to prosthodontic treatment. 10.81% had undergone crown lengthening in the lower arch due to endodontic treatment, 6.76% due to orthodontic treatment and 6.76% due to prosthodontic treatment. 1.35% had undergone crown lengthening in both the arch due to orthodontic treatment and 1.35% due to prosthodontic treatment. There was no statistical significance found between the association of arch and reason for crown lengthening (p value=0.487; p > 0.05). Crown lengthening due to endodontic treatment, prosthodontic treatment and orthodontic treatment was done more in the upper arch (figure 1).

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The distribution of gender and reason for crown lengthening was studied of which, 25.68% of males had undergone crown lengthening due to endodontic treatment, 10.81% of males due to orthodontic treatment and 9.46% of males due to prosthodontic treatment. 25.68% of females had undergone crown lengthening due to endodontic treatment, 17.57%% of females due to orthodontic treatment and 10.81% of females due to prosthodontic treatment. There was no statistical significance found between the association of gender and reason for crown lengthening (p value=0.678; p > 0.05). Crown lengthening due to endodontic treatment was done more in male and female. Crown lengthening due to prosthetic treatment was done more in males (figure 2).

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The distribution of age and reason for crown lengthening was studied of which, 17.57% of individuals who had undergone crown lengthening due to endodontic treatment were below 30 years, 25.68% of individuals due to orthodontic treatment and 10.81% of individuals due to prosthodontic treatment. 31.08% of individuals who had undergone crown lengthening due to endodontic treatment were between the age of 31 to 50 years, 2.70% of individuals due to orthodontic treatment and 6.76% of individuals due to prosthodontic treatment. 2.70% of individuals who had undergone crown lengthening due to endodontic treatment were above the age group of 51 years, and 2.70% of individuals due to prosthodontic treatment. There was a statistical significance found between the association of age and reason for crown lengthening (p value=0.001; p < 0.05). Crown lengthening due to endodontic treatment was done more between the age group of 31 to 50. Crown lengthening due to prosthodontic treatment was done more in individuals below 30 years. (figure 3)

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The distribution of age and gender of the individuals who undergone crown lengthening was studied of which, 29.73% of the individuals were male and 24.32% of the individuals were females below 30 years of age. 16.86% of the individuals were male and 25.68% of the individuals were females between 31 to 50 years of age. 1.35% of the individuals were male and 4.05% of the individuals were females above 51 years of age. There was no statistical significance found between the association of age and reason for crown lengthening (p value=0.216; p > 0.05). Crown lengthening was done more in males below 30 years. (figure 4)

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This study states that most of the individuals, equally males and females, had undergone crown lengthening for endodontic therapy. Endodontic therapy includes RCT, restoration of subgingival caries, post and core single crown etc. A study by Al Sowygh shows the importance of crown lengthening in restorative dentistry [28]. Gummy Smile has been a restorative challenge for orthodontics to achieve aesthetic smiles. Gingival enlargement has been a common problem in orthodontic patients [29]. Study done by Ifthikhar et al showed the need for aesthetic crown lengthening in the orthodontic population. Arghavan Amini et al stated that individuals who were between the age group of 31 to 50 years need to undergo crown lengthening due to endodontic treatment over other age groups. Individuals with less than 30 years of age preferred crown lengthening due to aesthetic reasons (gummy smile post orthodontic treatment) [30]. This study shows that females had undergone laser crown lengthening more and it's done mostly in the upper arch.

Acknowledgement and Declarations

The authors are thankful to the dental institute for providing a platform to perform the research study. The authors declare no conflicts of interest.