Introduction This purpose of this systematic review was to evaluate the literature and update our current understanding of the impact of present cancer therapies on the dental apparatus (teeth and periodontium) since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies. Review method A systematic literature search was conducted with assistance from a research librarian in the databases MEDLINE/PubMed and EMBASE for articles published between 1 January 1990 and 31 December 2008. Each study was independently assessed by two reviewers. Taking into account predetermined quality measures, a weighted prevalence was calculated for the prevalence of dental caries, severe gingival disease, and dental infection. Data on DMFT/dmft, DMFS/dmfs, plaque, and gingival indexes were also gathered. The level of evidence, recommendation, and guideline (if possible) were given for published preventive and management strategies. Results Sixty-four published papers between 1990 and 2008 were reviewed. The weighted overall prevalence of dental caries was 28.1%. The overall DMFT for patients who were post-antineoplastic therapy was 9.19 (SD, 7.98; n = 457). The overall plaque index for patients who were post-antineoplastic therapy was 1.38 (SD, 0.25; n = 189). The GI for patients who were post-chemotherapy was 1.02 (SD, 0.15; n = 162). The weighted prevalence of dental infections/abscess during chemotherapy was reported in three studies and was 5.8%. Conclusions Patients who were post-radiotherapy had the highest DMFT. The use of fluoride products and chlorhexidine rinses are beneficial in patients who are post-radiotherapy. There continues to be lack of clinical studies on the extent and severity of dental disease that are associated with infectious complications during cancer therapy.