Radiographic Assessment of 121 Glass Fiber Post Procedures in 32 Patients Aged 21–60 Years Performed by 6-Year Dental Students During the 2022–2023 Academic Year at the College of Dentistry, Jazan University, Saudi Arabia

Introduction

Rehabilitation of dental structures lost by trauma or caries requires adequate planning based on the clinical situation. The restoration of endodontically treated teeth (ETT) and severely damaged teeth has been a concern of clinicians [1], and researchers continue to seek the most adequate technique and material available in the field to restore such teeth. After endodontic treatment (ET), a proper restorative technique is necessary to ensure coronal seal [2,3] and protect the residual teeth structures [4], which have lost 2 or more walls and need to be restored with posts to increase retention and stability of the final restoration [5,6].

Prefabricated glass fiber posts (GFPs) have been widely used and show a relatively high success rate [7] because their properties are similar to those of dentin [8]. GFPs are more aesthetic, less expensive, and less invasive than metal posts and core systems [2,6]. Moreover, they are cylindrical and have a standardized diameter in accordance with the system. The manufacturers recommend the use of these posts in patients with a sufficient coronal tooth structure remaining [9].

The dental program in the College of Dentistry in Jazan University is a 6-year program. Students practice post preparation and construction throughout preclinical and clinical courses during their 4th and 5th years. The periodic assessment to determine the value of distributed services for patients are a vital signal for health service establishments. This assessment will expand quality of amenities and treatments provided by 6th-year dental students to their patients under faculty supervision. Outcomes gained will also offer authorities strong feedback about the academic organization and performance [10]. The clinical comprehensive course is a 1-year program including all dental disciplines, and it is a 5-session course per week with each session lasting 3 hours. The students are required to complete the course requirements before graduation.

GFPs can create a strong interface between root canal posts and dentin, which is essential for the long-lasting outcomes for ETT restored with a crown [11]. In a randomized controlled trial, GFPs showed good clinical outcomes, similar to cast metal posts [12]. Laboratory research found significant differences in fracture strength and failure pattern of the customized and GFPs [12]. Future surveys should assess the clinical and radiographical procedures performed after RCT and during GFPs construction to gain a broader picture of the experience students are gaining during their program [13].

A series of studies was conducted in the College of Dentistry, Jazan University. In 2017, Al Moaleem et al evaluated and compared the radiographic performance of different types of posts done by 6th-year undergraduate students. After an 18-month follow-up period, the GFPs achieved a success rate of 100% of ETT in comparison with other post types [11–15]. Thereafter, Meshni et al (2018) found that the maxillary and incisor teeth are the most frequently restored teeth with GFPs. Taper-shaped GFPs with one-third width of the root were the most common. Moreover, lengths of GFPs were twice (58%) the natural tooth or crown length. Over 50% of the examined cases showed 3–5 mm of remaining apical GP, while 75% of the cases exhibited no space between the post end and the apical GP [10]. In 2021, Alaki et al stated that 90% of the participants are aware of parallel and tapered posts, whereas 82% chose the use of GFP [12–16]. Recently, a radiographic study carried out by Naim et al (2023) measured the gap between the cemented post and residual GP for different post and core types in procedures performed by undergraduate students. About 65% of tested cases had more than 5 mm of remaining GP, and less than 3% had less than 3 mm of remaining GP. Almost 99% of treated teeth had no gap or spaces between the post end and the remaining GP [13–17]. In the same year, Sayed et al reported that radiographs showed a clinically acceptable outcome in terms of the gap between the post end and the remaining GP [14–18].

Periodic evaluation of the clinical performance of undergraduate students radiographically is mandatory to maintain a high and standard performance of students, as mentioned by the recommended textbooks. Therefore, this study aimed to undertake a radiographic assessment of 121 glass fiber post procedures in 32 patients aged 21–60 years performed by 6th-year dental students during 2022–2023 at the College of Dentistry, Jazan University, Saudi Arabia.

Material and Methods

STUDY DESIGN AND ETHICS APPROVAL:

For this cross-sectional radiographical study, ethics approval was approved by the Research Committee, College of Dentistry, Jazan University (CODJU-2315F on June 12, 2023). Informed consent was obtained from all patients selected for the study. GFPs fabricated by the 6^th-year dental students during the academic year of 2022–2023 were evaluated radiographically. This study was conducted in accordance with the guidelines of the Declaration of Helsinki.

DATA COLLECTION AND INTERPRETATIONS:

The data included in this radiographic study were based on the information presented in the logbook and CS-R4 program (CSR4 Software, Carestream Dental LLC, USA). This system has 1 screen and software program for measurements. The radiographic quality of the GFPs were independently evaluated by 2 experts with same level of experience and certificates, and the result was recorded when there was an agreement between the 2 examiners. The intra-examiner reliability was calculated by rechecking a random selection of 15 periapical X-rays of anterior, premolars, and molars teeth of the total GFPs previously examined. A.S and M. AL agreed in 80% of the cases. After that, the second-round agreement increased to 94%, indicating that the scoring methods were reliable.

DATA SCORING:

The following parameters and their definitions were recorded [19–22]: total number and ages of patients; Arch type (maxillary or mandibular) and tooth type (anteriors, premolars, and molars); post shape (taper or parallel) and post width in relation to width of root mesiodistally (1: 3, 1: 4, and 1: 2); length of post in relation to the crown (2: 1, 1: 1, and 3: 2) and root lengths (2: 3, 1: 1, and 2: 1); amount of remaining GP between 3 and 5 mm, more than 5 mm, extruded beyond the apex, and unsatisfactory condensation; presence of any radiographic abnormality in the root (No) or (Yes) in the form of widening of periodontal ligament, periapical pathosis, deviation of post from the canal, and fitting of post-to-root wall; and presence of spaces between the end of the post and residual GP (yes or no). Table 1 shows the parameters and their definitions.

STATICAL ANALYSIS:

All relevant data of prefabricated GFPs were collected and recorded in a self-designed form. The data were summarized and analyzed as frequencies and percentages using the SPSS (version 23), and associations between variables were determined using chi-square tests. The P value of 0.050 was considered significant.

Results

A total of 32 patients with 121 GFPs were assessed in this cross-sectional study. The participants were treated by 18 male 6th year dental students. The patients were ages 21–60 years, with a mean age and standard deviation of 31.83±9.446 years. The highest number of posts were for the maxillary teeth with 107 (88.4%), followed by 71 (58.7%), 33 (27.3%), and 17 (14.0%) for anterior, premolars, and molar teeth, respectively. All of the posts were tapered in shape. Almost the same GFP width in relation to mesiodistal width of the root was observed: 61 (50.4%) and 56 (46%) for 1: 3 and 1: 4, respectively. In relation to the post length to the length of crown, the highest number was for 2: 1 with 86 (70.1%), which was similar to post length and root length at 85 (70.2%). The amount of remaining GP at >5 mm accounted for more than two-thirds of the total number of posts. Abnormalities were present in 75.2%, whereas 82.6% were associated with absence of space between the GP and post (Figure 1).

Table 2 shows the relation of post width with the tooth type. The highest number and percentage of the GFP width was found in anterior teeth (40, 56.3%) for 1: 4, but it was over 2: 3 among premolar and molars. Anterior teeth recorded the highest number in length of post in relation to crown length (59, 83.1%) and root length (57, 80.3%). All the parameters recorded a significant difference with P values of 0.018 and 0.000. Similar significant P values (0.001) were recorded in relation to the amount of remaining GP, abnormality, and space between residual GP and post end. The remaining GP with >5 mm recorded the highest number among the different types of teeth, especially in anterior teeth (56, 78.9%). The absence of abnormality and the absence of spaces between GP and end of post were recorded in 91 (75.2%) and 100 (82.6%) of the total number of restored teeth, as represented in Table 3.

Figure 2 shows different periapical radiographs of GFPs with their related parameters. Figure 2A shows the 1/3 of post width in relation to mesiodistal width of the root. Figure 2B displays 2/3 of post length in relation to lengths of crown and root. Figure 2C shows the amount of remaining GP and post end. Figure 2D shows the presence of radiographic abnormality, and Figure 2E, shows an absence of the space between post and residual GP.

Discussion

Post space preparation and post cementation are routine and basic skills taught to undergraduates in many dental schools [23,24]. As a graduation requirement, dental students must carry out various clinical procedures, including the placement of post and core in ETT, followed by the final prosthetic restoration [10]. During their clinical years, students perform these procedures according to meticulously designed rubrics for each step. Their faculty mentors closely supervise these procedures to ensure the optimal outcome at each stage of the treatment plan [10]. Thus, these steps ensure a thorough evaluation of students’ practice and skill levels, aiding in the enhancement of their self-assessment ability in each particular dental procedure.

This radiographic cross-sectional study aimed to assess the quality of GFPs performed by the male students at the College of Dentistry, Jazan University during the 2022–2023 academic year. Overall, the results of the current study were in parallel with previous studies [10,23,25] in terms of post width, post length, remaining GPs, and space between GP and post end [17,18].

The findings of the current study showed that 88.4% of the posts were cemented in maxillary teeth, which was consistent with previous studies [10,26–28]. Moreover, we found that anterior teeth followed by premolars were the most treated teeth; this result disagreed with the findings of previous studies [23,25,27,29] reporting that premolars are the most frequently restored teeth with post and cores by undergraduate dental students. This contradictory result could be explained by the fact that they assessed all types of posts, but only GFPs were assessed in our study. However, other studies showed that incisors are the most frequently restored teeth with posts, followed by premolars [10,28]. Students’ choice of teeth for treatment may be influenced by the ease of post preparation and placement. Thus, many students tend to favor treating single-rooted teeth because of the potential for encountering various complications when dealing with multi-rooted teeth, such as perforations and root fractures [30]. This tendency might be a valid explanation for the low percentage of molars treated with GFP in this study. Among the different types of teeth, mandibular teeth were the least frequently retained by posts (11.6%); Meshni et al (2018) and Jamani et al (2005) reported similar findings [10,26]. This result can be due to difficulty in isolation, presence of saliva, and tongue movements that can obscure vision and affect the quality of post restoration [31].

Metal post stiffness may risk root fractures. Recent biomechanical advancements and a focus on aesthetics led to prefabricated non-metallic posts with an elastic modulus close to that of dentine [32–34]. In the present study, tapered GFPs were used in all cases of EET because of the high numbers of tapered GFP systems available for use in dental markets. These posts exhibit superior flexibility, offer mechanical and physical properties that meet acceptable standards, and contribute to a decreased likelihood of root fractures [32,33]. Also, these posts have shown satisfactory clinical performance throughout more than 2 years of practical application [35]. A clinical study determined that the insertion of GFP beneath final restorations enhances the support for restorations, resulting in a decreased likelihood of fractures and failures compared with alternative metallic post types [36,37]. Al Moaleem et al recorded a high success rate of GFPs after a 1.5-year follow-up period radiographically for posts implanted by final-year students. Therefore, most studies recommend the use of GFP whenever possible [15].

There is ongoing debate regarding the optimal post length; certain studies propose that increased post length enhances fracture resistance, while others argue that no correlation exists between post length and fracture resistance [38,39]. Therefore, absolute guidelines for optimal post length are difficult to define. Ideally, the post should be as long as possible without jeopardizing the apical seal or strength and integrity of the remaining root [19,22,28]. Maintaining an apical seal of 5 mm is considered satisfactory [17,18]. In cases of GFP, its length should not be shorter than or equal to clinical crown length [19,22,38,39]. Additionally, an optimal ferrule should be present [40]. Others recommended that post length should be half the root length [19,22,39], midway between the apex and alveolar crest [41].

The diameter of clinically acceptable posts should be one-third of that of roots [19,22,34,41]. About 50.4% of the presented cases evaluated in this study were equal to one-third of the root diameter. This result was similar to that reported by Almaghrabi et al [25], but high values of 82%, 80%, and 89.1% were reported by Meshni et al, Mendonca et al, and Mathar and Almutairi, respectively [10,27,29]. Nevertheless, the results of the current study were higher than the findings of Nimigean et al, who reported 41%. Moreover, a ratio of 1: 4 was reported in about 46.3% of the total cases [34]. This result was attributed to the high occurrence of treated maxillary anterior teeth, leading to the highest percentage of post width, which was prevalent in anterior teeth (56.3%). Anterior teeth post is always higher in width than posts of other tooth types [23,42].

Mechanical stress is concentrated at the alveolar crest during mastication, so the post should always extend beyond the alveolar crest, leaving a space of 4 mm for GP at the apex [19,22]. Fortunately, the post length: crown length ratio of 2: 1 reached 71.1% of the cases in the present study, indicating that it was superior to that reported by Al-Hamad et al and Meshni et al [10,28] but equal to that reported by Almaghrabi et al, who evaluated 661 digital periapical radiographs of posts performed by 6th-year dental students (74% of 2: 1 ratio of post length: crown) [25]. Acceptable length, which equals crown length, was found in 21.5% of the included cases; this number was lower than that reported by Jamani et al (32.14%) and Meshni et al (37.9%) but higher than that by Almaghrabi et al (19%) [10,25,26]. The present findings agreed with those of Alshehri et al (2023), who reported that post length was equal to or more than crown height in all cases (100%) [43].

The present study showed good ratios of post length in relation to root length, that is, 2: 3 and 1: 1 in 70.2% and 26.4% of the cases, respectively. These values were contrary to proportions described by Nimigean et al, who reported a high percentage of short posts (66.07%) in their study [34]. However, our results were similar to the GFPs reported by Jamani et al (2005), who reported that about 70% of the evaluated cases do not exhibit an ideal root canal filling [26]. This observation can be attributed to the high number of GFPs used in our study, the ease of handling during work, and use of rotary systems during canal preparation; most of the restored teeth were single-canal ETT. Recently, Alshehri et al (2023) and Baik et al reported slightly high percentages in relation to the two-thirds root length [23,43].

The length of remaining GP that is needed to maintain apical integrity and a proper apical seal should range from 3 mm to 5 mm [15]. This length was found in 23.1% of the cases in our study; this percentage was lower than that reported by Al Maghrabi et al, who applied similar criteria in their cases [25]. They observed 3–5 mm of remaining GP in 68% of the cases at King Abdulaziz University. Another study conducted at Jazan University reported that 55.7% of the evaluated cases fell within the same range of remaining GP. This result was probably because most of the treated cases in our study were anterior teeth. Thus, leaving >5 mm of GP is justifiable if the post is more than half the root length [23], which explains the high percentage (68.6%) of remaining GP in our study. The condition and amount of the remaining GP were within the recommended and international standard and reached 82.7% (total of more than 5 and between 3 and 5 mm). Similar results were recorded by many previous studies [10,16,23,25].

The presence of gaps between the post and residual GP can have significant consequences. These gaps may contribute to increased microleakage, providing a pathway for microorganisms to infiltrate the root canal system [44]. The size of these gaps is crucial, as large gaps have been associated with a high risk of periapical disease development. Notably, a gap exceeding 2 mm has been identified as a potential trigger for periapical disease in many cases [18].

The presence of gaps between GP and GFP was reported in 17.4% of cases in our study, similar to that reported by Mathar and Almutairi (2020) [29]. However, this value was much higher than that reported by Naim et al (2023), who examined the evolution of gap between cemented posts and residual GP in undergraduate students and reported a percentage of 60% [17]. Therefore, attention must be paid to the elimination of gaps during post placement in endodontic procedures, as well as proper sealing and adaptation of materials.

There are many differences between the current study and the previous study conducted in the same college. The previous study compared between male and females, other type of posts were included, and the number of students was much higher than in this study. Also, the students: supervisor ratio was completely different as the staff to student ratio was 1: 7 in the current study.

One of the limitations of the present cross-sectional radiographical study is the small sample size in comparison with previous studies conducted in the same institute. First, we evaluated the GFPs only. Second, the samples included male students with similar supervisors in relation to clinical experiences and certificates. Third, the total number of male students were lesser in this study in comparison with that in previous bathes.

Conclusions

Maxillary and anterior GFPs were the most tested radiographs. Significant differences with the tested parameters were observed in relation to the location and position of teeth. Post width, post length in relation to crown length or root length, and the amount of remaining GP were acceptable and within the recommended values and procedures in the textbook. Overall, the performance of students in performing GFP radiographically was within a high standard.