Knowledge, Awareness, and Use of Stainless-Steel Crowns Among Dental Professionals in Sana’a City, Yemen

Introduction

Dental caries is a common disease among young children [1]. According to the World Health Organization, dental caries affects 60–90% of schoolchildren in developed and developing countries [2–4]. Dental caries remains a chief health issue in Yemen, as it is in other developing countries, and its incidence continues to increase [2,5].

Primary teeth play an important role in chewing and speaking and act as a natural space maintainer in the dental arch, so taking care of decayed teeth is important [6]. The treatment of extensively decayed primary teeth involves various challenges for pediatric dentists, such as saving remaining tooth structure, and obtaining parent approval [7].

Stainless-steel crowns (SSCs) are among the most durable, retentive, and inexpensive restorative supplies now available [8]. In general, SSCs are the first choice for restoration of caries-related defects in primary teeth, and they have been the most effective and efficient method of tooth restoration in pediatric dentistry [9,10]. SSCs are also considered as a favorable restoration method for primary molars with 2 surface lesions and larger carious lesions because of their notable clinical success [11–13]. In addition, they are utilized to restore fractured teeth, multi-surface caries, and post-endodontic restoration in young permanent and pediatric dentition [14–19]. Despite their full coronal coverage [20], the main disadvantage of SSCs is their silvery metallic appearance [20–22].

Traditionally, full caries removal and tooth preparation were regarded as necessary before fitting SSC, typically requiring local anesthesia [8,23,24]. Subsequently, the Hall technique was introduced, which involves placement of SSC over carious primary molars without the injection of local anesthesia, tooth reduction, or caries removal [25]. This technique can be used for treating young children with limited attention spans or as a way to improve patient cooperation [24,26].

SSCs has better durability and longevity than amalgam and tooth-colored restorations in primary dentition [27]. Recently, Joshi et al and Alqadi et al (2023) reported that SSCs showed better longevity [28] and radiographical outcomes [29] than the other restorative materials on primary molars. Cementing of SSCs on permanent molars is an extremely effective long-term temporary restorative dental treatment that conserves severely damaged molars in adolescents until definitive prosthetic treatment [30].

Overall, SSCs have shown consistently high success rates during clinical and questionnaire-based studies [20,31], as mentioned in studies used conventional or Hall techniques [8,26,32,33], or in retrospective, prospective, observational, or randomized control studies [13,24,34]. However, despite approval and indication for clinical use, SSCs are rarely utilized by general dentists [34–41].

Many studies have assessed knowledge, awareness, and use of SSCs globally [21,22,35,38,42,43]. Other studies have used SSCs clinically to restore primary and permanent molars and have compared the performance of SSCs with that of other restorative materials [23,36–38,40,41]. All of the abovementioned studies concluded that SSCs are effective for restoring molar teeth.

A school-based survey conducted in the Sana’a governorate of Yemen discovered that schoolchildren in Yemen had a high incidence of dental caries and a huge number of untreated decayed deciduous teeth [44]. Also, there is little information available on success rates of SSCs as a restorative treatment for primary teeth, their use in clinical practice, and the reasons for parents’ unwillingness to have SSCs used in their children. Therefore, the current survey study aimed to assess the knowledge, awareness, and use of SSCs by dental professionals in children in Sana’a City, Yemen.

Material and Methods

STUDY DESIGN AND ETHICAL CONSIDERATION:

The present cross-sectional study was designed to assess the knowledge and practice of dental practitioners in the use of SSCs in Sana’a City, Yemeni. Ethics approval was gained from the Medical Research Ethics Committee of at Sana’a University (PE: 05/05/2024). Participants were provided with a summary of the study’s objectives along with the questionnaires to obtain their consent. The study was conducted in compliance with the Declaration of Helsinki guidelines [45].

INCLUSION AND EXCLUSION CRITERIA:

This study included both genders of Yemeni dental professionals practicing dentistry in government hospitals or private dental clinics in Sana’a, Yemen. We excluded non-Yemeni dental professionals and dentists who do treat primary teeth.

SAMPLE SIZE CALCULATION:

The sample size for the current study was determined on the basis of the number of dental practitioners in Sana’a City, Yemen, with the effect sample calculated at 95% power and a significance level of α=0.05 [46]. A total of 604 dental professionals were randomly selected from dental clinics, dental colleges, and government and private hospitals.

STUDY SETTING AND POPULATION:

A cross-sectional, face-to-face questionnaire study was performed for dental professionals from September 2023 to May 2024. Copies of questionnaires were sent through WhatsApp to different groups at different clinics and colleges. A simple random sampling technique was used to obtain samples from different geographical areas in Sana’a City by utilizing a computer and software.

QUESTIONNAIRE TOOLS AND DATA COLLECTION:

A questionnaire survey was modified from previous similar studies [21,22,35,38,43]. It was used as an instrument for data collection, and the participants were assured that all information was confidential and protected. The questionnaire was translated into Arabic with the assistance of a native Arabic speaker, and then the questions were exposed to forward and backward translation into English [46].

The validity, reliability, and clarity of the questionnaire was confirmed by administering it to 20 volunteers from different dental professions who were asked to respond to the questionnaire and to comment on its clarity, content, and brevity. The participants could select more than 1 answer for each question, could only complete the questionnaire once, and all questions had to be answered. The answers were directly documented and collected from the respondents.

QUESTIONNAIRE PARTS:

The questionnaire was anonymous and had 3 parts. The first part was related to the characteristics of participants, such as gender (male and female), academic qualification (BDS, MSs, and PhD), specialty (general dentist, pedodontics, prosthodontist, and other specialty), working experience (up to 5 years, 6–10 years, 11–20 years, and ≥21 years), and type of work place (private, general, or specialized public hospital).

The second part was related to knowledge and awareness of SCC questions and consisted of 7 questions: “Which indications would oblige you to use SSCs in primary teeth?”, “Which indications would oblige you to use SSCs in permanent teeth?”, “What are the most important advantages of the use of SSCs in your opinion?”, “Have you faced challenges related to the use of SSCs?”, “What are the main barriers to your use of SSC”, “Why would the parents of your patients reject the use of SSCs”, and “How do you know about SSC restorative technique”.

The third part included questions related to SSC practice and consisted of 3 questions regarding the “use of SSCs in clinical practice,” “number of children treated per week,” and “number of SSCs used per week.”

In addition, there was a question related to mode of education and gaining information related to SSCs (lecture, illustrated guidelines, hands-on course, video demonstration, and webinar). There was also a question regarding to the age range of children receiving SSC restorations (>3 years, between 3–6 years, and <6 years). To obtain more information on the practice of participants in the use of SSCs, question related to type of education were asked. After collecting the answered questionnaires, the answers were numbered and arranged in an Excel sheet for statistical analysis.

STATISTICAL ANALYSIS:

Data were manipulated using SPSS version 25. Incidence distributions were utilized for descriptive statistics. The confidence interval (95% confidence level was used) and chi-square test were used to test the associations between dentists’ demographic characteristics and the use of preformed metal crowns (PMCs), as well as to compare general versus pediatric dentists with regard to the number of children treated and SSCs used per week. Statistical significance was set at P<0.05.

Results

PARTICIPANT CHARACTERISTICS:

Of the 700 questionnaires distributed, 627 responses were received, and 23 respondents were excluded because of incomplete answers. A total of 604 questionnaires were completed, with a response rate of 86.3%. Of the participants, 229 (37.9%) were male, 494 (81.8%) had bachelor’s degrees, 110 (18.2%) were dental specialists (MSc or PhD), and only 15 (2.5%) were pedodontists. Of the respondents, 17 (2.8%) had more than 20 years of professional experience and 347 (57.5%) had less than 5 years of experience, 228 (74.2%) of the participants were working in private dental clinics or hospitals, and only 49 (8.1%) were working in specialized hospitals (Figure 1).

Most respondents (73.7%; n=445) did not use PMCs in their clinical practice, and only 26.3% (n=159) of the dental professionals reported using readymade SSCs in their clinical practice. The use of PMCs was significantly linked with having a dedicated degree in pediatric dentistry, whereas only 120 (24.3%) of general dental practitioners reported using SSCs, and more than three-quarters of pedodontist used SSCs (80.0%, P<0.05). In addition, this study showed a statistically significant relationship (P<0.05) between the academic qualifications of dentists and use of SSCs in daily dental practice. Dentists with a PhD were more likely to use SSCs than dental professionals with other qualifications such as MSC and BDS (Table 1).

KNOWLEDGE- AND AWARENESS-RELATED QUESTIONS:

Of the 159 SSC users, 100 (62.9%) indicated they used SSCs in primary molars after pulp therapy, followed by deep multi-surface caries (75, 47.2%), while 72 (45.3%) and 71 (44.7%) stated that they used SSCs in permanent teeth, endodontically-treated molars, and deep multi-surface caries. The most common challenge of use of PMCs in clinical practice was problems in crown alteration (109, 68.6%), followed by aesthetic appearance (61, 38.4%) and crown detachment (23, 14.5%). In addition, among those who reported using SSCs, 127 (79.9%) learned this restorative technique at college, 21 (13.2%) were self-taught, and only 8.8% learned this restorative technique through media programs (Table 2).

Among the 604 contributors, maintaining function and occlusion (454, 75.2%) was the most frequently reported advantage of readymade SSCs, followed by long durability and a good prognosis (268, 44.4%). In response to the question “What are the main barriers to use of preformed metal crowns,” among the 445 respondents who reported not using SSCs, 141 (31.7%), 130 (29.2%), 128 (28.8%), 118 (26.5%), 95 (21.3%), 80 (18.0%), and 42 (9.4%) answered lack of practical training in the use of performed SSCs, non-compliance by children, aesthetic concerns, lack of knowledge of SSCs, unawareness of SSCs, lack of materials and equipment, and low charge/low input–output ratio, respectively. In relation to the problems associated with parents’ refusal to use SSCs, of the 604 participants, 223 (60.9%), 155 (42.3%), 100 (27.3%), and 56 (15.3%) answered that parental rejection was due to a deficiency of understanding of the benefits, price and cost, an aesthetic reason, and non-compliance of children, respectively (Table 2).

PRACTICE-RELATED QUESTIONS:

In this study, 12 (80.0%) out of 15 pediatric dentists and 120 (24.3%) out of 494 general dentists used the SSC restorative technique. The number of children per week who received SCC services by pediatric dentists was higher than that of general dentists, whereas more than two-thirds of general dentists treated less than 5 children per week. In addition, most pediatric dentists treated 4 or more children per week, and the difference was statistically significant (P<0.05). Moreover, the number of SSCs used per week by pediatric dentists was higher than that used by general practitioner dentists. Half of pediatric dentists used more than 5 SSCs per week, whereas 87 (72.5%) of the general dentists used less than 2 SSCs per week (P<0.05) (Table 3).

With regard to multiple-response questions, of the 604 respondents who indicated that they would like additional training material and practical courses on using SSCs, 209 (43.9%) and 196 (41.2%) selected video demonstrations and hands-on courses as the preferred type of education or training, respectively (Table 4). Table 5 shows that most children (86, 54.1%) who received SSC restorations were 3–6 years of age.

Discussion

To the best of our knowledge, this survey is the first to assess knowledge about and clinical practice using SSCs among a group of dental professionals in Sana’a City, Yemen. The outcomes of this survey showed that SSCs are not widely used among Yemeni dental practitioners, with 26.3% of the respondents using SSCs in their practice. This finding is consistent with the earlier studies [22,34,35,38]. In a study conducted among dentists in Norway and Finland, only 12.0% and 12.9%, respectively, reported using readymade SSCs in their clinical practice [35]. By contrast, a study conducted in Chengdu City, China, found that most dentists (69.6%) did not use readymade SSCs to restore decayed primary molars [22,36]. Among dentists in Germany, 34% regularly used readymade SSCs [34], whereas only 3.0% of participants in the United Kingdom routinely used SSCs, 15% used them infrequently, and 82% never used them [38].

Table 1 shows a significant difference (P<0.05) between academic qualifications and specialty with the use of PMCs in clinical practice. This result is consistent with a previous study [22]. Dental practitioners with high academic qualifications are more likely to use the SSC system, which could be associated with SSC technique training at various stages of education. The present study documented that pediatric dentists (80%) were more likely to use SSCs than general dentists (24.3%), and this finding is consistent with other studies [22,35]. This difference was due to the lack of training among dental general practitioners. Pediatric dentistry postgraduate clinical education tends to focus on prefabricated metal crowns (PMCs) more than in undergraduate education. Thus, specialized dentists obtain more practical exercise under senior supervision, and more often use general anesthesia during treatment. According to Tseveenjav et al (2018), SSCs are used more commonly with general anesthetic treatments [39].

We found that pediatric dentists used SSCs to treat more children per week than general dentists (P<0.05), which suggests that the use of SSCs and inadequate training of general practitioners was weak in treating and managing young patients. These findings agree with the results of recent studies [22,47]. Shelton et al (2019) hypothesized that such a variance caused from lack of SSCs training of undergraduates and in continuing education courses after graduation [47]. Apart from professional training, pediatric dental consultants have an advanced, qualified understanding of children’s oral problems, have more experience in treating young patients, and are more familiar with the PMC technique [22,35,36].

In the present study, the main barrier to use of readymade SSCs among dentists was the lack of practical training (31.7%). This finding is consistent with the result of Uhlen et al (2021) [35] but not with the other results [22,34]. This result could be due to the limited clinical practice of undergraduate students in the use of PMCs, the low number of suitable pediatric patient cases that the dental students treated, and the lack of interest by general dentists in continuing education programs that provide practical training in the use of readymade SSCs. Threlfall et al (2005) reported that some dentists feel they have not received enough training during their undergraduate studies to perform SSCs [38]. Kowolik et al (2007) showed that general dentists are not interested in continuing education courses on use of PMCs [42].

Non-compliance by children was stated as the second barrier against SSC in this study, with 29.2% of dentist believing that it was a cause for their reluctance to use this technique. A similar issue was analyzed in a previous study, which examined dental practitioners’ views on using SSCs [38]. In addition, many of the dentists who did not use SSCs believed that a child would find it difficult to tolerate the procedure [38,47]. A further restriction to the use of SSCs was aesthetic concerns (28.8%), in comparison with the study carried by Santamaria et al (2018), in which the lack of aesthetics was the main reason for use of SSCs (43.5%) [34]. This result may be due to the lack of acceptance by the parents and their children of the appearance of metal crowns, which was one of the reasons for the parents’ refusal to use readymade SSCs in this study. In a study conducted by Threlfall et al (2005), the participating dentists mentioned that the parents did not like the appearance of the SSC; thus, SSC was not used [38].

A secondary care-based study also examined parents’ and children’s acceptance of SSCs. However, very few complaints (<6%) concerning the crowns’ look were made [48]. Maciel et al (2017) revealed that children seem to like the appearance of SSCs and tend to prefer a crown over other commonly used restorative materials [49]. Santamaria et al showed a good level of acceptance of crowns, with 88% of parents expressing satisfaction with the procedure [34]. Therefore, the appearance of metal crowns might be of more concern to aesthetically-oriented dentists than to parents or children.

In addition, the deficiency of knowledge about SSCs was reported as another barrier against SSC by 26.5% of respondents in this study, although 80% of the participating dentists said that they learned this restorative technique in college. The same barrier (lack of knowledge) was also the main barrier to use of readymade SSCs among dental practitioners in China, accounting for 41.7% [22], and only 10.9% of them learned this restorative technique in college. On the contrary, according to Santamaria et al, only 14.5% of German dentists thought the absence of knowledge about SSCs prevented them from using it [34]. These results emphasized the need for learning how to fit SSC restorations. The importance and knowledge of the SSCS technique should be taught during undergraduate education to facilitate its implementation. This will encourage dental undergraduates to acquire and apply the technique methodically during resident training in pediatric dentistry.

This study found that the main reason for parents’ rejection of using SSCs was the understanding of the benefits (60.9%), followed by prices (42.3%). This finding is in parallel with the outcome of a previous study [22]. Therefore, before beginning treatment, dentists should emphasize to parents the basis for the SSC restorative approach. Gaining the trust and understanding of children and their guardians is largely dependent on the attitudes and actual statement of dentists [50]. Furthermore, increasing public awareness of the value of pediatric dental health and disseminating children’s oral health knowledge are of great importance. The cost was the second most common reason (42.3%) for parents rejecting SSC restoration because of the financial difficulties faced by parents caused by the low per capita income and poor economic situation in Yemen. Of the participating dentists in this study, 62.9% thought primary molars after pulp therapy were the main indication for using PMCs, followed by deep multi-surface caries (47.2%). This result is inconsistent with the outcome of studies carried out earlier in other countries [22,34,35].

On the contrary, Bedre and Gurunathan (2019) found that 60.7% of dentists agreed that restoring primary teeth with crowns after pulpal treatment is necessary [43]. In permanent molars, endodontically-treated molars and deep multi-surface caries were frequently selected by dentists as main indications for using readymade SSCs in the current study, accounting for 45.3% and 44.7%, respectively, which is in contrast to that of Uhlen et al [2021], who found that among dentists in Norway and Finland, dental developmental defects were the most often chosen indication for PMCs (85.5% and 70.7%, respectively) [35].

We found that 68.6% of respondents indicated that the difficulty of crown adjustment was a major challenge. This result was consistent with other research [35]. This result may be due to the lack of practical experience with the use of SSCs among general dentists, as the results of this study indicated that most general dentists treated fewer children and used fewer crowns per week compared with pediatric dentists. The second most commonly mentioned challenge with the use of PMCs was aesthetic concerns (38.4%), which is consistent with the study of Uhlen et al [35]. Aesthetic concerns have been reported as a barrier to the use of readymade SSCs by dentists and parents, as parents desire a better aesthetic appearance. Similarly, other studies have reported that poor esthetics hinders the use of performed SSC [34,38].

However, a study found that most children and their parents viewed SSC positively and expressed slight or no concern about their color and appearance. The authors suggested that these results may inspire dentists who have been reluctant to use preformed SSCs because of aesthetic concerns [48]. As shown in Table 2, the most frequently reported advantage of SSCs among dentists was maintaining function and occlusion (75.2%). This finding is consistent with the results of the previous study conducted in Norway and Finland [35,36].

Most of the participants indicated that they would like more material and practical training courses on how to use SSCs. The results obtained from this study are consistent with those found by Uhlen et al. [35]. As shown in Table 2, the lack of practical hands-on courses was the most common reason for dentists not using SSCs. In addition, this finding shows the motivation and interest of dentists. The most popular type of education or training preferred by respondents in this study was video demonstrations, accounting for 43.9% of dentists, followed by a hands-on course (42.2%). These findings are inconsistent with those of the study conducted in Norway and Finland, with the majority choosing hands-on training as their chosen education format, accounting for 56.6% and 43.4%, respectively [35]. These findings support the lack of adequate clinical training. Thus, few children received SSC restorations (Table 5).

Children aged 3–6 years received SSC restorations, which accounts for 54.1% participants, with just 6.3% being younger than age 3. This result is similar to the findings obtained earlier [22]. SSC restoration is effective in crowning of primary molars for children under age 3 years [51], but the conventional way of placing SSCs is more difficult than the Hall technique, which requires more cooperation from young patients [38]. This limitation prevents children under age 3 from receiving SSC restorations.

This study has also some limitations. First, it focused on different dental professionals at Sana’a City, Yemen, and it did not include dentists from another governorate. Second, no comparative studies from neighboring countries were included to assess societal differences in knowledge, mentalities, and awareness. In addition, the questionnaire did not have open-ended questions. Finally, the questions did not cover all aspects of the knowledge, awareness, and practice of SSC use.

Conclusions

We found that SSCs are not widely used by general dental practitioners in Sana’a City, Yemen. The main barrier to SSC use among dentists was insufficient training, whereas parents’ rejection of SSCs was due to the absence of understanding of the benefits.

Most participants in this study were interested in getting more evidence and education about the use of preformed metal crowns. Therefore, dental education should have more emphasis on SSCs, and there is a need for practical courses for general dentists, reinforced by continuing education programs.