Background:In pediatric dentistry, fixed space maintainers are crucial for preserving the space in edentulous areas following premature tooth loss and promoting the healthy development of the dental arch, maxilla, and mandibula. A vital aspect in ensuring the long-term functionality of the space maintainer is the selection of the appropriate luting agent. Conventional glass ionomer cements (GIC), known for their chemical properties and biocompatibility, are widely regarded as safe and effective luting agents. Despite the prevalent use of resin cements (RCs) in modern dentistry, studies examining the effects of fixed space maintainers (FSMs) luted with resin cements (RCs) on periodontal status are lacking.

Material:This split-mouth design study involved 31 children aged 6 to 10 years who prematurely lost their mandibular second primary molars. The left mandibular first molars were bonded with FSM High-Q-Bond Band™ self-adhesive resin cement, while the right molars were bonded with Meron (conventional glass ionomer cement). Gingival Index (GI), Plaque Index (PI), and Periodontal Probing Depth (PPD) were measured before luting and at the 1-week follow-up. Gingival crevicular fluid (GCF) was collected from the abutment teeth using Periopaper® strips before luting and at the one-week follow-up. ELISA was then performed to measure the levels of the proinflammatory cytokine Interleukin-18(IL-18). Statistical Analyses involved the Mann-Whitney U test for comparing two groups of qualitative and quantitative variables, and the Wilcoxon Signed Ranks test for assessing differences between two dependent quantitative variables. A significance threshold of p < 0.05 was used for statistical inference.

Introduction Fixed space maintainers (FSMs) are important preventive orthodontic devices used in pediatric dentistry. These devices are specifically designed to preserve the spaces left by premature tooth loss or planned tooth extractions. Maintaining these spaces is crucial for guiding the proper eruption of permanent teeth, contributing to a child's healthy dental development. Pediatric dentists are the most frequently consulted professionals during this stage, and their preventive practices significantly impact the preservation of the edentulous space during the transition from mixed dentition to permanent dentition.

The primary objective of all types of space maintainers in primary and mixed dentition is to preserve arch length by preventing space loss within the dental arch. Space loss may occur as a result of the mesial migration of teeth positioned distal to an edentulous area through tipping, or due to the distal drifting of teeth that remain mesial to the edentulous region. The type and design of space maintainers employed to preserve the edentulous spaces resulting from premature loss of primary teeth are contingent upon various factors. These factors include the number of teeth that have been lost in the affected area, the stage of the child's dental development, and the specific dental arch where the space maintainer is to be applied. Considering all these factors, FSMs are the most preferred option among the various types of space maintainers, as they remain unaffected by jaw or dental arch conditions.

Preventing malocclusions in a developing child due to the premature loss of primary teeth is crucial. This can be accomplished by using a space maintainer as soon as possible after a tooth extraction. This can protect the space left by the missing tooth and help maintain the proper arch length as the child continues to grow. FSMs need to remain cemented in the mouth for an extended period, as even a matter of days can be significant in this process. To achieve optimal results, the cementation process must be conducted with durable luting cement. Traditionally, it has been advised to cement FSMs using conventional glass ionomer cement (GIC). However, over the past decade, resin cement (RC) has become increasingly prevalent due to significant advancements in bonding technology and the rising adoption of adhesive resin cement within dentistry.

While resin cement has been employed to enhance the survival of FSMs, it is crucial to note that research investigating periodontal inflammation in children arising from residual cement following the FSM cementation process is lacking. Numerous inflammatory cytokine biomarkers indicate the presence of gingival inflammation. Pro-inflammatory cytokines, tumor necrosis factor(TNF-α), anti-inflammatory cytokines, and host factor metalloproteinases play significant roles in regulating inflammatory responses. Interleukin-18 (IL-18) is a significant pro-inflammatory cytokine belonging to the Interleukin-1 (IL-1) family. It is essential in the immune response to infections and various diseases. The function of IL-18 in the inflammatory response is to facilitate the expression of adhesion molecules on endothelial cells, thereby increasing the recruitment of immune cells to the site of inflammation. The accumulation of IL-18 in regions that are persistently exposed to irritants triggers chronic tissue damage, facilitating the progression of the disease's pathogenesis. The role of IL-18 in immune regulation and inflammation suggests that it may serve as a potential biomarker for tracking the progression of various diseases. Studies have indicated that the expression levels of IL-18 are significantly elevated in gingival crevicular fluid and gingival tissue samples associated with gingival inflammation and periodontal diseases.

Gingival crevicular fluid (GCF) is recognized as the primary medium for analyzing alterations in the local tissue environment, thereby facilitating the assessment of periodontal health and disease. This fluid is instrumental in understanding the physiological changes occurring in periodontal conditions. The noninvasive collection of biomarkers in GCF is an essential diagnostic method for accurately assessing gingival health in clinical settings.

Upon re-evaluating the FSM treatment protocol in light of this information, it becomes clear that FSMs are frequently cemented within the gingival pocket in cases where they come into contact with the gingiva. Current literature remains unclear about inflammation effects in the periodontal sulcus caused by the use of resin cement for luting space maintainers. The null hypothesis of this study posits that FSMs luted with conventional GIC and those luted with resin cement result in identical alterations in IL-18 levels within the GCF of pediatric patients.

Inclusion Criteria:

• Children who have not received any antibiotic treatment in the past four months,
• Children who do not have any underlying systemic diseases.
• Children who are not required to take medication regularly,
• Both girls and boys between the ages of 6 and 10.
• The second primary molar teeth (75 and 85) were extracted from patients due to caries and associated periapical pathologies.
• The presence of the succeeding tooth germ.
• Pediatric patients exhibiting Angle Class I occlusal relationships.
• Children without skeletal abnormalities.
• Existence of the antagonistic tooth of the abutment tooth.
• Children and their parents willing to participate in the study and attend the control session one week later were included.

Exclusion Criteria:

• The patient presents with periodontal disease.
• Children with cognitive disabilities, including autism and attention deficit hyperactivity disorder, as well as those with mental health conditions such as cerebral palsy and Down syndrome.
• Children and their parents who did not meet the specified criteria were excluded from the study.