The aim of this study was to test whether the combination of diode laser therapy and surgical treatment for a lateral periodontal cyst (LPC) would result in greater clinical improvement compared with surgery alone. A total of 18 patients with LPCs were assessed for eligibility for this study. At baseline, each patient was randomly allocated to one of two regimens: diode laser plus surgery (test group) or traditional surgical treatment alone (control group). Healing parameters were assessed at 7 to 21 days to monitor short-term complications, and periodontal parameters were assessed at 3, 6, and 12 months to evaluate long-term healing. The test group demonstrated highly significant differences in both the short-term and long-term parameters compared with the control group. This study showed that diode laser treatment results in a shorter wound-healing period and could be considered valuable for the surgical treatment of LPCs.