Objectives The aim of this study was to evaluate changes in mean probing depth and clinical attachment level at disto-buccal aspect of adjacent mandibular second molar following removal of third molar after socket treatment with either allograft putty or customized allograft bone block. Materials and Methods 30 patients underwent extraction of a lower mesio-angular impacted third molar; and they were divided into three treatment groups. Group 1 received allograft putty, and Group 2 received customized allograft bone block in the socket while patients in Control Group 3 did not receive any bone substitute. Probing depth and clinical attachment level at disto-buccal aspect of adjacent mandibular second molar was measured at 1 week, 3 months, 6 months and 12 months post-operative. Pain score and complications were assessed. Results Reduction in probing depth over time between groups was not significant. Customized allograft bone block group showed higher clinical attachment loss compared to allograft putty treatment. Pain scores were significantly higher in both the intervention groups and post-operative complications were highest in the customized allograft bone block group. Conclusions Socket preservation following third molar extraction using either allograft putty or customized allograft bone block did not show favorable results for mitigating postoperative probing depth and clinical attachment loss at disto-buccal aspect of adjacent second molar . Clinical Relevance Augmentation of lower third molar extraction socket with bone allograft to mitigate probing depth and clinical attachment loss at adjacent second molar does not show favorable results compared to leaving the socket to heal alone.