Purpose: This study aimed to assess the alteration in keratinized mucosa (KM) dimensions in

the early healing period after implant placement, and the influence of variables obtained during

implant surgery on KM alteration. Materials and Methods: Study participants were consecutively

recruited from patients who had received implants following a non-submerged surgical protocol.

The implant had to be installed in the extraction socket that had healed for more than 6 months

without any soft or hard tissue augmentation. Keratinized mucosa width (KMW), keratinized

mucosa thickness (KMT), soft tissue level (STL), and probing pocket depth (PPD) were

measured at implant placement and 3 and 6 months after implant surgery. The influence of

variables obtained during implant surgery on the 6-month KMW alteration was assessed. Results:

A total of 66 implants in 55 patients who completed the follow-up examination after 6 months

were included in this study. KMW, KMT, and STL significantly decreased at 3- and 6-months

examination by 0.7–1.2 mm. KMW was reduced by 24.6%. Mesial PPD significantly increased

between the 3- and 6-months follow-up. In the multivariate generalized estimating estimations

analysis, the implant diameter negatively influenced the 6-month KMW alteration, but the KMW

at implant surgery positively influenced the 6-month KMW alteration. Conclusions: The KMW

decreased significantly at 3 and 6 months after implant placement. If the initial KMW was wider,

the KMW was reduced more at 6 months after implant placement. Therefore, it is important to

carefully monitor KMW alterations during the early healing period to ensure optimal esthetics

and peri-implant tissue health.