Introduction

A dull smile has social repercussions. Demand for improved and beautiful smiles has become integral to dental procedures [1]. Many people, especially young females, are concerned about their smiles because the first thing people notice when meeting a new person is their smile [2]. In the present era, patients increasingly demand a perfect smile due to a shift in priorities and the impact of the media [3, 4].

Since teeth color is interrelated to each individual's aesthetics, teeth discoloration is frequently reported among patients seeking aesthetic treatment [5]. The practice of whitening the teeth is known as bleaching. Through bleaching, oxidation occurs within the enamel, making it look lighter than before [6]. Bleaching is a minimally invasive process used to treat discolored teeth [7].

The popularity of teeth whitening has climbed many-fold with the availability of over-the-counter bleaching agents. Recent advances in aesthetic dentistry have led to a wide selection of teeth whitening products. These include toothpaste, dentifrices, and gels. In addition, lifestyle habits like smoking, and consumption of black tea and coffee, may lead to darker-colored teeth [8]. Generally, bleaching products are classified into two categories, i.e., home and in-office bleaching products. Besides hydrogen peroxide, which is widely used as a bleaching agent, chlorides, peroxides, and chlorine are sometimes also used. Along with the active agent, inactive constituents such as glycerine to maintain moisture, gelling to enhance the viscosity, preservatives such as methyl or sodium benzoate to prevent bacterial growth, and flavoring agents to improve taste are also used in the product [9].

A past survey revealed that 25.6% of the dental patients used saline, and 10% used lemon as a home-based dental whitening agent [10]. Another study showed that the patients were inclined to choose advertised and home bleaching products compared to professional bleaching [1]. In addition, a survey of the association between age, sex, level of education, marital status, and type of work on the perception and knowledge of patients regarding teeth whitening products has been reported previously [5].

Despite the benefits of teeth bleaching, there are evident side effects such as increased teeth sensitivity [11], irritation of gingivae and mucous membrane [12], weakening of the dentin and enamel damage [13], and demineralization of the teeth surface [1] and most of Saudi Arabia's population is unaware of the adverse effects of teeth bleaching. Therefore, this cross-sectional study aims to assess the knowledge of at-home and In-office teeth bleaching and their adverse effects amongst the general population in Saudi Arabia.

Materials and Methods

This analytical cross-sectional survey-based study was designed and targeted across Saudi Arabia to measure the population's knowledge of at-home and in-office teeth bleaching. A non-probability convenience sampling method was adopted to collect the data from individuals aged ≥18 and collected from March 2021 to May 2021. Participation in this survey was voluntary. Informed consent was taken from the participants, and the purpose of this study was explained before participants' enrollment. The confidentiality of the participants was assured throughout the study without collecting personal identifier information.

An online structured questionnaire was developed using Google forms. The authors of this study shared the survey link using e-mails, WhatsApp, and other social media applications with their contacts. The online questionnaire made it impossible to submit the form without filling in the entire field. Therefore, the participants were encouraged to roll out the survey further to achieve maximal participation. Ethical approval (FUGRP/2021/219/386/384) for the study was obtained from the Research and Innovation Center of Riyadh Elm University, Riyadh, Saudi Arabia.

This cross-sectional study with a snowball sampling method was conducted in all of Saudi Arabia. A modified close-ended questionnaire in Arabic/English was available for the participants. No personal data except gender, age, and level of education would be collected from the participants.

A modified questionnaire based on previous research conducted by Alshamrani and Wahid was used to meet the current research requirements [2]. The questionnaire comprised of three parts:

Part 1: Four questions related to socio-demographics (Age, gender, educational level and  area)

Part 2: Five questions on causes of teeth discoloration and sources of information

Part 3: Seven items on knowledge about teeth bleaching, including at-home and in-office teeth bleaching methods.

Part 4: Six items on knowledge of adverse effects of teeth bleaching.

Pilot testing of the questionnaire demonstrated excellent reliability (Cronbach's alfa=0.91) and face validity.

Statistical analysis

Descriptive statistics of frequency distribution and percentages were calculated for all the categorical variables. The chi-square test assessed the relationship between categorical variables. A p-value of less than 0.05 was considered significant for all statistical purposes. Statistical analysis package IBM-SPSS version 25 (Armonk, NY: USA) was used for the data analysis.

Results and Discussion

A total of 2065 participated in this study. The number of male and female respondents was 45.6% and 54.4%, respectively. Nearly 64.3% of the study participants were aged between 20-30 years, and 44.7% of participants had a postgraduate level of education. Moreover, 47.9% of the subjects belonged to the central region of Saudi Arabia (Table 1).

Table 1. Demographic variables of the study participants (n=2065)

Knowledge of Causes of teeth discoloration

Table 2. Knowledge of teeth-discoloration causes among study participants

When asked about the causes of teeth staining, 88.2% of the study participants mentioned tea, coffee, smoking/tobacco, and shisha as all causes of teeth staining. In addition, nearly 27.7% and 59.6% of subjects agreed that antibiotics (tetracycline and doxycycline) and aging causes teeth staining. Moreover, more than half, 51.5%, of the participants attributed teeth staining to intrinsic and extrinsic causes (Table 1).

Knowledge and source of information on teeth-bleaching among study participants

Almost 99.3% of the study participants were knowledgeable about teeth bleaching. The primary source of information for the study participants was advertisements (34%), followed by dentists (33.3%) and family friends (Figure 1).

Almost half  (48.9%) of the respondents were aware of products (Toothpaste, White strips, and gels) used at home for teeth whitening. In addition, 89.1% of the study participants agree that dentist-supervised bleaching is more effective than home bleaching, and 41.5% knew that the beaching of teeth under dentist supervision is usually a one-day process. Moreover, 67.2% of subjects knew that dentist-supervised bleaching concentrated bleaching agents are used compared to home-based bleaching products (Table 3).

Table 3. Knowledge of teeth bleaching among study participants (N=2065)

Nearly 61.5% of the study participants mentioned that they know the adverse effects of home-based whitening/bleaching products. However, when asked about the adverse effects of the dentist's supervised whitening/bleaching products, 62.2% responded positively. In addition, study participants were knowledgeable about the temporary teeth-whitening of bleaching products (83.8%), teeth sensitivity (81.2%), wearing of enamel surface (60.7%), and gum and mucus membrane irritation (64.6%), following the bleaching treatment (Table 4).

Table 4. Knowledge of adverse effects of teeth bleaching

Table 5. Knowledge of teeth bleaching and adverse effects across different demographic variables