Digital health tools are increasingly embedded in dental care to enhance prevention, treatment efficiency, and access. This systematic review synthesized original studies evaluating health informatics interventions in dentistry across clinical, operational, and patient reported outcomes. We included nine original studies: randomized trials and quasi experimental designs assessing smartphone tooth brushing applications, AI enabled remote monitoring during orthodontics, tele dentistry service models, SMS appointment reminders, web assisted e referrals for smoking cessation, and AI chatbot education. Across orthodontic settings, smartphone or chatbot interventions generally improved plaque and gingival indices or patient knowledge, while an AI remote monitoring platform reduced plaque, lesion progression in short term follows up; one clear aligner study found no meaningful difference between remote and conventional monitoring in malocclusion improvement. SMS reminders and tele dentistry pathways supported attendance and service reach, and e referrals increased engagement with cessation support. Patient reported outcomes favored digital modalities for satisfaction, perceived convenience, and acceptability. Heterogeneity in outcomes, follow up length, and fidelity limited meta-analysis; consistent signals suggest that well designed informatics tools can improve oral hygiene behaviors and streamline care. Future research should standardize outcome sets, extend follow up, and evaluate equity, costs, and implementation fidelity.