## 4 Discussion  
The present study was based on the null hypothesis that periodontal parameters, GCF volume and GCF cytokine (IL-6 and TNF-\(\alpha\)) levels in patients treated with lumineers would be comparable before and after treatment. It was observed that ceramic luminescent treatment showed similar clinical periodontal parameters and GCF cytokine profile (IL-6 and TNF-\(\alpha\)) levels from baseline to 24-week follow-up. Therefore, the postulated null hypothesis was accepted. Multiple explanations for these outcomes include ceramic biocompatibility, oral hygiene improvements, socio-economic status of patients, and expertise of treatment providers. Primary use of lumineers were emphasized to the advantage of patients who did not want their teeth to be prepared [5]. Lumineers, due to their higher esthetics, biocompatibility, and clinical longevity, are considered as an alternative to complete-coverage restorations [24]. Studies suggest that researches are focused mostly on esthetic and technical aspects of ceramic veneers [25; 26]. However, investigations pertaining to gingival and periodontal outcomes of ceramic lumineer restorations are limited and showed heterogeneous results. In addition, an appreciation of restoration and periodontal interface is critical in determining the successful clinical outcomes and to ensure satisfactory function, form and esthetics of the dentition [27]. GCF levels of inflammatory cytokines (IL-6 and TNF-\(\alpha\)) have found to be increased in different inflammatory conditions. Cytokine balance plays an important part in stability and early progression of inflammation, however their detrimental role in progression of periodontal disease is gaining strength [15; 17; 28]. Macrophages and T-cells secrete TNF-\(\alpha\), which play important role in early induction of periodontal inflammation. Furthermore, it may synergistically stimulate human gingival fibroblasts to enhance IL-6 secretion. Elevation of both IL-6 and TNF-\(\alpha\) causes periodontal and gingival breakdown via disturbances in lipid metabolism [29]. It is also suggested that IL-6 exerts its influence by myeloid cell differentiation, up-regulation of B lymphocytes and T cell populations [17]. IL-6 therefore amplifies the host response and regulates periodontal tissue homeostasis through stimulation of osteocl activity and growth of periodontalopathogenic bacteria [30]. Moreover, increased IL-6 levels are reported in periodontitis and a significant decrease in its level following periodontal therapy indicates its role as an early disease onset biomarker for periodontal inflammation [17; 31]. Figure 4: Comparison of IL-6 and TNF-\(\alpha\) pg/mL as observed at baseline and different follow-up durations in patients treated with lumineers. The results of the present study demonstrated that PI and BOP scores at week 4 were significantly higher from the baseline. There are multiple reasons accredited to this outcome. Considering the esthetic requirement, most of the lumineers' margins in the present study were placed subgingivally or equigingivally, this might have caused reversible damage to the junctional epithelium and connective tissue [32]. Furthermore, subgingival margin tends to accumulate more plaque and exerts potentially undesirable effects on the health of surrounding tissues. Moreover, the role of soft tissue manipulation during margin preparation, gingival retraction, and impression making cannot be neglected. In addition, a direct relationship exists between over contouring and soft tissue inflammation, as it causes plaque accumulation and soft tissue disturbance due to change in emergence profile. Furthermore, undetected excess cement in the sulcus area might also have contributed to this outcome [33]. Interestingly, PI and BOP findings become comparable to the baseline at week 12 and 24. In addition, PPD and CAL remains unaffected after lumineer placement and appeared comparable to baseline at 4, 12, and 24 weeks follow-up.