TITLE - COMPARATIVE EVALUATION OF STREPTOCOCCUS MUTANS ADHESION, ORAL HYGIENE STATUS, AND CLINICAL SUCCESS IN PRIMARY MOLARS RESTORED WITH PREFORMED STAINLESS STEEL CROWNS, TITANIUM-NITRIDE COATED STAINLESS STEEL CROWNS, AND VITRIFIED COMPOSITE CROWNS: A RANDOMIZED CONTROLLED TRIAL

INTRODUCTION - Stainless steel crowns (SSCs) have been widely used to restore primary teeth that are badly decaying and carious, and teeth requiring pulp therapy procedures or where other restorative materials are ineffective. SSCs are considered one of the best full coverage restorative materials because of easy placement as they are inexpensive, and have the desirable longevity. Braff stated that SSCs were significantly superior to multi-surface amalgams in the restorations of primary molars. Despite its poor aesthetics, it has been extensively used due to its resistance. The development of periodontal disease and secondary caries is thought to be significantly influenced by the adherence and colonization of oral microorganisms on dental surfaces and restoratives. According to research done both in vivo and in vitro, Streptococcus mutans (S. mutans) is one of the bacteria that are isolated from plaque samples from natural to artificial surfaces during the early stages of the development of caries. The first step in a microorganism’s colonization process is the organism’s adherence to a host surface. Accordingly, the assessment of Streptococcus mutans adherence on dental surfaces and restorative materials is crucial to the effective completion of these procedures. Surface-related characteristics, such as roughness, free surface energy, surface tension, wettability, hydrophobicity, hydrophilicity, electrostatic interactions, and microhardness, are among the necessary materials used in dental restorations. These characteristics are clinically significant because they may have an impact on plaque accumulation and staining. Microorganisms will cling more readily to surfaces with higher surface free energy; conversely, a more hydrophobic surface will result in less predicted adherence of microorganisms9. For primary teeth, the prefabricated crowns are available in various sizes and have a well-defined contour. Traditional prefabricated SSCs are widely utilized, and one of the most common issues connected to SSC is gingival tissue inflammation. Bacterial plaque causes gingivitis surrounding restorative materials10. Despite the extensive use of stainless steel crowns in the Pediatric patients, one cannot ignore the fact that they lack antimicrobial properties. Therefore, Titanium nitride coated crowns have been introduced recently. The crown seems bright and golden because of the titanium-nitride coating. The coating might contribute to the surface’s increased hardness. Also, Biradar R. et al (2024) concluded that the microbial adhesion of Streptococcus mutans and plaque accumulation was seen less on the Titanium-coated SSC when compared with conventional SSC, which was statistically significant11. Recently, new preformed aesthetic crowns have been introduced in the market which are manufactured using laser sintering procedure and consist of Vitrified Composite. They have similar flexural modulus as that of natural tooth. They also claim to be highly antibacterial and plaque resistant; however, the comparison of adhesion of microorganisms, especially Streptococcus mutans on Pediatric vitrified composite crowns against Titanium-coated stainless-steel crowns has not been reported before and towards this aim; Also, comparative clinical durability of these crowns has not been evaluated yet. Therefore, we aim to conduct a randomized trial to compare the Streptococcus mutans adhesion, oral hygiene and clinical success of conventional preformed stainless steel crowns with Ti-coated stainless steel crowns and vitrified composite crowns on primary molars.

METHODOLOGY - 

Study Design:

Multi-arm, prospective, randomized controlled trial.

Study Setting:

Conducted in the Department of Pediatric and Preventive Dentistry and Microbiology Laboratory after ethical clearance.

Study Population:

Children aged 4–8 years requiring pulpectomy in primary molars.

Sample Size:

60 teeth (20 per group), calculated using OpenEpi software, considering a 15% dropout rate.

Sampling Technique:

Simple random sampling using AI-generated random allocation tables.

Group A: Stainless Steel Crowns

Group B: Vitrified Composite Crowns

Group C: Titanium-Nitride Coated Stainless Steel Crowns

Inclusion Criteria:

Children aged 4–8 years

Primary molars indicated for pulpectomy with sufficient remaining tooth structure

Cooperative patients (Frankl’s positive behavior)

Written parental consent

Exclusion Criteria:

Special needs children

Severely decayed or infra-occluded teeth

Malocclusions, parafunctional habits

Allergies to local anesthetics, chromium, or nickel

Subject Withdrawal:

Voluntary exit, non-compliance, or meeting exclusion criteria later.

Study Materials:

Three types of crowns: stainless steel, titanium-nitride coated, vitrified composite.

Procedure Overview:

Pulpectomy followed by crown placement per standard guidelines for each crown type.

Crown cementation:

SSCs and TiN crowns: Glass ionomer cement

Vitrified composite crowns: Composite cement with etching and bonding

Outcome Measures:

Streptococcus mutans adhesion: Evaluated at baseline, 3, 6, and 12 months via plaque sampling, cultured on MSB agar.

Oral Hygiene Status: Plaque and Gingival Index recorded at each follow-up.

Clinical Success: Assessed using Modified USPHS criteria for retention, occlusion, crown integrity, occlusal wear, marginal adaptation, anatomical form, and secondary caries.

Follow-up Period:

Baseline, 3 months, 6 months, and 12 months.

Data Recording:

Systematic documentation at each follow-up.