Dental insurance policies typically exclude coverage for treatments or services that were initiated before the policy's effective date. This is a standard "work in progress" or pre-existing condition exclusion designed to prevent adverse selection, where an individual purchases insurance solely to cover a known, ongoing, and expensive procedure. Insurance is intended to cover unforeseen or future needs, not to retroactively pay for care that has already begun.

B. Preventive care: This is a core covered benefit in most dental plans, often covered at the highest percentage (e.g., 100%), as it helps prevent more costly future procedures.

C. Dental X-rays: These are a standard diagnostic and preventive service. They are almost universally covered, typically falling under the preventive or basic care benefit categories.

D. Root canal therapy: This is a major restorative procedure. While it is subject to deductibles and higher coinsurance, it is a standard covered service under most comprehensive dental plans.

1. Virginia Bureau of Insurance, "A Consumer's Guide to Accident and Sickness Insurance" (2022). While a general guide, the principles apply to dental insurance, which is a form of health insurance. The guide discusses common exclusions, stating policies typically do not cover "services received before the policy's effective date." (See section on "Exclusions and Limitations").

2. American Dental Association (ADA), "Glossary of Dental Benefit Terms." The ADA defines "Pre-existing Condition" and related terms, noting that a dental plan may exclude coverage for charges incurred for a condition that existed before the enrollee's effective date. The concept extends to work already in progress. (Available at ADA.org).

3. Bhattacharyya, N., & Penchas, R. Z. (2018). Dental Benefits: A Guide to Dental PPOs, HMOs, and Other Managed Plans. In chapters discussing plan design and limitations, the text explicitly identifies "services started prior to the date of eligibility" as a common exclusion in dental benefit contracts to manage liability and risk.