A 10 year old male patient complains of a gap between his upper front teeth. Intra-oral examination reveals a midline diastema of 2 mm, for which a removable appliance with finger springs was given. What type of anchorage is seen with this appliance?
**Core Concept**
The question requires understanding of anchorage in orthodontics, specifically the type of anchorage used in removable appliances. Anchorage refers to the resistance offered by the surrounding teeth and bone to the movement of teeth during orthodontic treatment. In removable appliances, anchorage is achieved through various means, including the use of springs, elastics, and clasps.
**Why the Correct Answer is Right**
The use of a removable appliance with finger springs in this case indicates that the type of anchorage being used is **distal anchorage**. Distal anchorage refers to the resistance offered by the posterior teeth to the movement of the anterior teeth. The finger springs exert a force on the posterior teeth, creating a distal force that helps to close the midline diastema. This type of anchorage is commonly used in removable appliances to achieve anterior movement or closure of spaces.
**Why Each Wrong Option is Incorrect**
**Option A:** **Buccal anchorage** refers to the resistance offered by the buccal alveolar bone to the movement of teeth. This type of anchorage is not relevant to the use of finger springs in a removable appliance.
**Option B:** **Pendulum anchorage** is a type of anchorage used in fixed appliances to achieve posterior movement of molars. It is not applicable to the use of finger springs in a removable appliance.
**Option C:** **Torus anchorage** refers to the use of the palatal torus as a source of anchorage in fixed appliances. This type of anchorage is not relevant to the use of finger springs in a removable appliance.
**Clinical Pearl / High-Yield Fact**
In removable appliances, the type of anchorage used depends on the specific orthodontic goal and the patient's anatomy. Understanding the different types of anchorage is crucial in designing effective treatment plans and predicting treatment outcomes.
**Correct Answer:** D.