This study assessed the effects of buccal contour augmentation for periodontally compromised teeth with horizontal bone loss. A total of 30 subjects were divided into Group A or Group B (n = 15 subjects per group). Group A received open-flap debridement (OFD) with buccal contour augmentation using deproteinized bovine bone mineral (DBBM), jointly referred to as contour augmentation for periodontal defects (CAPD; test group). Group B received only OFD (control group). Bleeding on probing (BOP), clinical attachment level (CAL), probing depth (PD), gingival recession (GR), keratinized mucosa width (WKM), keratinized mucosa thickness (TKM), and labial cortical plate thickness were compared at baseline and 1 year. BOP, CAL, PD, and GR did not show significant differences. TKM increased by 1.76 mm for Group A but decreased by 1 mm for Group B. WKM increased from 2.86 ± 0.4 mm to 3.6 ± 0.71 mm (P < .001) and from 2.93 ± 0.32 mm to 3 ± 0.7 mm (P = 0.5) for Groups A and B, respectively, which showed statistical significance. Labial cortical plate thickness increased from 0.94 ± 0.3 mm to 1.95 ± 0.54 mm (P < .001) for Group A but decreased from 0.87 ± 0.45 mm to 0.68 ± 0.31 mm for Group B. Visual analog scale scores for pain perception showed no difference between the two groups. CAPD for periodontally compromised teeth improves WKM and TKM. Long-term analyses are needed to determine its benefits in daily clinical practice.