| Title: Comparative evaluation of microneedling with vitamin C and vitamin C alone in the management of thin gingival phenotype: A split mouth randomized clinical trial. introduction: The periodontium is formed by supporting tissues which invest the tooth i.e., the root cementum, periodontal ligament, bone lining the tooth socket (alveolar bone) and the part of gingiva facing the tooth. [1] The gingiva is the part of the oral mucosa that covers the alveolar processes of the jaws and surrounds the necks of the teeth. [2] Variation in gingival and osseous architecture have shown significant impact on treatment outcomes. Hence gingival phenotype has to be evaluated. Ochsenbein and Ross in 1969 suggested 2 main types of gingival anatomy, flat and highly scalloped. [3] Later on, in 1989 Seibert and Lindhe proposed the term ‘Gingival Biotype’ and defined it as the thickness of gingiva in facio-palatal direction, which was classified as thick flat and thin scalloped. [3] A gingival thickness of ≥ 2mm is considered as thick tissue biotype and <1.5 mm is referred as thin tissue biotype. [4] In 2017, the World Workshop of Periodontics advocated the term ‘phenotype’ instead of biotype.[4] Phenotype refers to the collection of traits or characteristics, it is determined by the interaction of genes and the environment.[2] Gingival phenotype is a combination of gingival thickness (GT) and the keratinised tissue width (KTW) whereas, periodontal phenotype is referred as the combination of gingival phenotype and bone morphotype (buccal bone thickness). [5] A thin gingival phenotype, in addition to a lack of KTW, is more prone to gingival recession.[5] Thick tissue phenotype has been associated with better outcomes following corrective periodontal procedures, such as root coverage with coronally advanced flap. Gingival phenotype has a significant impact on the outcome of the restorative, regenerative and implant therapy. [4] Various surgical and non-surgical methods have been employed to increase gingival thickness that includes pedicle flap, soft tissue grafts and xenogeneic collagen matrix.[6] However, recent advancements in management of thin gingival phenotype include the use of novel non-invasive materials like i-PRF and hyaluronic acid.[5] The concept of microneedling (MN), a minimally invasive technique was developed in 1994 and since 1995 it has been practiced in cosmetic dermatology.[7] Microneedling refers to a non-surgical procedure also known as ‘percutaneous collagen induction therapy’. [7] It was first used in dentistry by Zeliha Betul Ozsagir and co-authors. MN induces microinjuries resulting in minimal superficial bleedings along with creation of wound- healing cascade releasing various growth factors like platelet-derived growth factors, transforming growth factors, connective tissue growth factor and fibroblast growth factors. Thus, the tissue responds to these microinjuries leading to increased body’s own collagen production. Fibroblasts produce collagen and elastin fibres by migrating to the point of intrusion for wound closure. Newly formed fibres thicken the tissue during a process known as neocollagenesis. Fibroblasts also trigger neoangiogenesis by stimulating the proliferation of endothelial cells in the vessels. [8]
Vitamin C, a water-soluble vitamin with abundant antioxidant property, is a cofactor for two enzymes, lysyl and prolyl hydroxylases, responsible for collagen hydroxylation. Its vital role in biosynthesis, function of collagen, and extracellular matrix along with promotion of gene expression of fibroblasts have shown a great potential in regenerative medicine. Due to lack of enzyme L-gluconolactone it cannot be synthesized in humans. Apart from dietary supplements Vitamin C is available as oral tablets, chewable tablets, creams, serum, transdermal patches and injectable form of vitamin C. In the present study injectable form of vitamin C (100mg) will be used with the help of insulin syringe,[11] and microneedling will be performed using dermapen.[12] Thereby, the study aims at comparative evaluation of microneedling with vitamin C and vitamin C alone in the management of thin gingival phenotype. Study design: Randomized clinical trial (split mouth study) Study setting: The study will be conducted in clinical setting in Department of Periodontology. Study population: The study will include 25 patients diagnosed with thin gingival phenotype and categorized into two groups, Group 1: microneedling + vitamin C injection Group 2: vitamin C injection alone Sample size estimation: Sample size was estimated by using the data obtained from previous study conducted by Gupta S et. al. (Journal of Clinical Periodontology. 2020 Nov, 47(4): 489-499). This calculator uses the following formulas to compute sample size: (σ12+ σ22) (Z1-α/2 + Z1-β)2 n = --------------------------------- (μA – μB)2 where, σ1 is standard deviation of 1st group (pre) = 0.05 σ2 is standard deviation of 2nd group (post) = 0.05 μA is mean of 1st Group (Pre) = 0.17 μB is mean of 2nd Group (Post) = 0.13 α is Type I error = 0.05 β is Type II error = 0.20 i.e., 1 – β is power = 80% Z1-α/2 = two-sided Z value (eg. Z=1.96 for 95% confidence interval). Z1-β = 0.84 for 80% power Substituting these values in above-mentioned formula, the sample size estimated was n = 25 samples. Methods of selection: Inclusion criteria: 1. Age ≥18 years diagnosed with thin gingival phenotype (≤1mm) [5] in maxillary and/or mandibular anterior region. 2. Patients willing to participate in the study Exclusion criteria:[8] 1. Systemically compromised patients 2. Heavy smokers (>10 cigarettes per day) 3. Pregnant or lactating women 4. Patients who have been previously undergone periodontal therapy 5. Patients with active orthodontic treatment 6. Aggressive or chronic periodontitis Materials required 1. Mouth mirror, explorer 2. University of North Carolina number 15 probe (UNC15) 3. Digital vernier calliper 4. Topical local anaesthetic agent 5. Endodontic K file 15 number [5] 6. Injectable vitamin C 7. Sterile Gauze 8. Normal saline for irrigation 9. Five ml syringe and needle 10. Insulin syringe with Needle 11. Dermapen with cartridge [12] Clinical parameters:[8] 1) Gingival thickness (GT) 2) Keratinised tissue width (KTW) 3) Plaque index (PI) 4) Gingival index (GI) 5) Bleeding on probing (BOP) 6) Probing depth (PD) 7) Clinical attachment level (CAL) Method: [8,11,12,21] First visit: After obtaining informed written consent and detailed case history from the patient, all the participants will undergo phase-I therapy. In this split mouth study, 25 patients with thin gingival phenotype in the maxillary and/or mandibular anterior region will be selected and randomly allocated to one of the two groups by flip coin technique. MN+vitamin C injection will be performed on one side and vitamin C injection will be administered on the other side. In MN+vitamin C group, microneedling will be performed using microneedling device (dermapen) to induce bleeding and after thorough irrigation with normal saline, a saline soaked gauze will be placed between the gingiva and lip to control bleeding. Then 1ml vitamin C (100mg) will be injected with the help of 30G insulin needle 2-3mm apical to the gingival margin, on the both sides. Same procedure will be repeated for next three visits with the interval of 1 week. Follow up: The following parameters will be assessed at one month and three months from the baseline: Gingival Thickness, Keratinised Tissue Width, Plaque Index, Gingival Index, Bleeding on Probing, Probing Depth, Clinical Attachment Level. Statistical analysis: Statistical analysis will be carried using SPSS software v26. Level of significance will be kept at 5%. Data will be subjected to normality testing using Shapiro wilk test. Depending on the results of normality testing, intragroup comparison of change in each variable within each group between different time intervals will be performed using either repeated measure ANOVA test or Friedman test. Intergroup comparison of each variable, comparison of each variable between two groups will be performed using independent t test or Mann Whitney test.
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