**Question:** Which among the following is least hygienic pontic?

A. Crown-on-crown pontic
B. Bar-supported pontic
C. Fixed partial denture (FPD) with cervical abutment tooth
D. Implant-supported pontic

**Core Concept:** A pontic is a false tooth used in prosthodontics to replace missing teeth in a dental bridge or fixed partial denture (FPD). Hygiene refers to the ease with which a dental restoration can be cleaned to prevent plaque accumulation and reduce the risk of gum disease and tooth decay.

**Why the Correct Answer is Right:** Among the given options, the least hygienic pontic is the **Crown-on-crown pontic**. This type of pontic is not fixed to any abutment tooth and is only held in place by marginal adaptation and seating on the abutment crowns. Consequently, it is more prone to plaque accumulation, food retention, and difficulty in cleaning compared to the other options.

**Why Each Wrong Option is Incorrect:**

A. **Crown-on-crown pontic**: As explained above, this type of pontic is least hygienic due to its lack of fixed connection to abutment teeth.

B. **Bar-supported pontic**: Although less hygienic than implant-supported pontic, a bar-supported pontic has better hygiene compared to a crown-on-crown pontic due to its connection to abutment teeth.

C. **Fixed partial denture (FPD) with cervical abutment tooth**: This option is incorrect because it assumes that a pontic attached to a cervical abutment tooth would be more hygienic than a pontic attached to an incisal abutment tooth. However, both types have similar hygiene levels, as they are fixed to abutment teeth and not directly related to the type of abutment tooth.

D. **Implant-supported pontic**: This option is incorrect as it suggests that the implant-supported pontic is less hygienic compared to an implant-supported crown. However, both an implant-supported pontic and an implant-supported crown are hygienic, as they are all-implant supported, ensuring easy access for oral hygiene maintenance.

**Clinical Pearl:** When selecting a pontic type, factors like retention, stability, and esthetics should be considered, while ensuring the pontic is easily cleanable for optimal oral hygiene.