In Vivo Pulp Thermal Changes During Different Slenderization Techniques

Study Objectives The primary goal of this investigation is to evaluate the in vivo (inside the body) temperature rise within the dental pulp (the living tissue inside the tooth) when different techniques of Interproximal Enamel Reduction (IPR) are performed.

The core aims are:

• To measure and compare the magnitude of pulp temperature increase across two common IPR methods.
• To determine if any of the evaluated techniques have the potential to raise the pulp temperature above a critical threshold (5.5 degrees C), which is historically associated with irreversible pulp damage.
• To identify which IPR technique carries the highest possibility of thermal injury.

Rationale and Significance Previous studies that looked at this issue were performed ex vivo (on extracted, non-living teeth). This study is crucial because it measures temperature changes in live, intact teeth under actual clinical conditions, providing a more reliable assessment of risk.

A key difference in this research, compared to other literature, is the inclusion of both incisors (front teeth) and premolars. Since the enamel thickness on incisors is generally less than on premolars, there is a possibility that the heat generated during IPR may transfer more readily to the pulp in the anterior teeth, potentially leading to a greater temperature rise and a higher risk of adverse thermal effects. This study aims to clarify this potential risk.

Study Design and Methods This is a randomized clinical trial, an in vivo study involving participants undergoing orthodontic treatment where tooth extraction is required.

Participant Population The study will involve participants for whom the extraction of specific teeth (premolars and incisors) has been clinically advised as part of their orthodontic treatment plan. These teeth will be used for the IPR procedures just before they are extracted.

Procedure Groups (Interventions)

The teeth will be randomly assigned to one of the following two IPR technique groups, with the potential for each to generate a different amount of frictional heat:

• High-Speed Air-Driven Drill (Airotor and Bur): This method involves high rotational speed (potentially over 300,000 RPM) and thus has the highest possibility of causing the greatest temperature elevation due to intense friction.
• Orthodontic IPR Kit (Oscillating System): This technique operates at a much lower speed (around 5,000 RPM) and is expected to result in a moderate temperature increase, presenting a moderate possibility of thermal effect compared to the high-speed drill.

Measurement Prior to the IPR procedure, local anesthesia will be administered. A sensitive thermocouple directly on the surface of tooth to meausre baseline temperature of the pulp.

The chosen IPR procedure will be performed. The temperature changes in the pulp will be monitored at two time points and recorded during the IPR process.

The data gathered will be used to compare the techniques and determine the relative possibility of thermal damage posed by each method, particularly within the incisors, which are uniquely included in this research.

Inclusion criteria

• Participants 12 to 25 years of age.
• Participants undergoing orthodontic treatment requiring extraction of the teeth being studied (Incisors or Premolars).
• Selected tooth must be intact (no decay, large fillings, or fractures).
• Tooth must test vital (alive and healthy) prior to the procedure.
• Tooth must have healthy surrounding gum tissue.

Exclusion criteria

• Teeth that are non-vital (dead), have root canal treatment, or signs of irreversible pulpitis.
• Teeth with existing large or deep restorations (fillings) or crowns/veneers.
• Teeth that have undergone any previous IPR or stripping procedure.
• Teeth with significant developmental enamel defects (e.g., severe hypoplasia or fluorosis).
• Participants with severe systemic diseases (e.g., uncontrolled diabetes) affecting dental health.
• Participants taking medications that affect pulp sensation or vascular response (e.g., long-term anti-inflammatories).
• Participants who are pregnant or breastfeeding.