Effect Of Keratinized Gingival Width On Peri-implant Soft And Hard Tissue Health In The Posterior Region

Objective To evaluate whether different peri-implant keratinized gingival widths(greater than or equal to 2 mm or less than 2 mm)affect the peri-implant soft and hard tissue health in the posterior region at 1 year after restoration,and to analyze the correlation between the peri-implant soft and hard tissue health in the posterior region and the implant site(maxillary or mandibular)and the type of defect(free or non-free)at the implant site when the peri-implant keratinized gingival widths are different,in order to provide a clinical reference for the implant treatment of patients with different underlying conditions.Methods A total of 192 implant sites were included in 100 patients with dental defects in the posterior region who visited the Hangzhou Zhongyi Dental Clinic from June 2019 to June 2020,all of whom were simple implants and met the uniform inclusion criteria.The clinical indexes such as gingival index,bleeding on probing,probing depth,marginal bone loss,etc.were measured immediately after the completion of the implant prosthesis and at the follow-up after 1 year,and the incidence of peri-implant mucositis and peri-implantitis was counted in each group according to the immediate buccal angular gingival width at the completion of the implant upper restoration.The peri-implant soft and hard tissue health of each group was evaluated based on the modified plaque index,gingival margin recession,and marginal bone resorption at the immediate post-restoration and 1-year follow-up visits,and whether the difference in peri-implant keratinized gingival width had an effect on the peri-implant soft and hard tissue health in the posterior region.The correlation between the implant site and the type of dental defect(maxillary free-end,maxillary non-free-end,mandibular free-end,mandibular non-free-end)and the peri-implant soft and hard tissue health in the posterior region was further analyzed while the peri-implant keratinized gingival width varied.SPSS 22.0 was used for statistical analysis of the data.Results 1.At the individual patient level,during the observation period of this study,88%(88)of the patients had no substantial inflammatory lesions around the implants and 12%(12)of the patients had at least one implant mucositis around the implants.At the implant level,there were no substantial inflammatory lesions around 80.7%(155)of the implants.Implant mucositis was present around 19.3%(37)of the implants.No peri-implantitis was present at both the patient level and the implant level.2.The incidence of peri-implant mucositis,modified plaque index,gingival margin recession,and marginal bone resorption in the keratinized gingiva greater than or equal to 2 mm group was less than in the keratinized gingiva less than 2 mm wide group,with statistically significant differences(p<0.05).3.When the peri-implant keratinized gingival width was less than 2 mm,the differences in the incidence of peri-implant mucositis,modified plaque index,gingival margin recession,and marginal bone resorption were statistically significant(p<0.05)in the maxillary free-end,maxillary non-free-end,mandibular free-end,and mandibular non-free-end groups.The mandibular free-end absence group had the largest indexes,and the differences in modified plaque index,gingival margin recession,and marginal bone resorption between the mandibular free-end absence group and the rest of the groups were statistically significant(p<0.008).The maxillary non-free-end loss group had the least marginal bone resorption,and the differences in marginal bone resorption between the maxillary non-free-end loss group and the rest of the groups were statistically significant(p<0.008).When the peri-implant keratinized gingival width was greater than or equal to 2 mm,the differences in the incidence of peri-implant mucositis and modified plaque index among the maxillary free-end,maxillary non-free-end,mandibular free-end,and mandibular non-free-end groups were not statistically significant(p>0.05),and the differences in gingival margin recession and marginal bone resorption among the groups were statistically significant(p<0.05).The gingival margin recession in the mandibular free-end absence group was greater than that in the maxillary non-free-end absence group,and the difference in gingival margin recession between the two groups was statistically significant(p<0.008).The maxillary non-free-end loss group had the least marginal bone resorption,and the difference in marginal bone resorption between the maxillary non-free-end loss group and the rest of the groups was statistically significant(p<0.008).Conclusion During the observation period of this study,the difference in keratinized gingival width affected the peri-implant soft and hard tissue health in the posterior region;the incidence of peri-implant mucositis was lower in posterior region implants with keratinized gingiva greater than or equal to 2 mm than in posterior region implants with keratinized gingiva less than 2 mm wide;the peri-implant soft and hard tissue health(modified plaque index,gingival margin recession,marginal bone resorption)in posterior region implants with keratinized gingiva greater than or equal to 2 mm Better than posterior zone implants with angulated gingival width less than 2mm The soft and hard tissue health around implants in the posterior region with mandibular free-end loss and keratinized gingival width less than 2 mm is poorer and the biological risk is higher.In order to ensure the long-term health and stability of the hard and soft tissues around the implant,the presence of keratinized gingiva of 2 mm or more in width around the implant should be ensured as much as possible within the biological width allowed.