A critical evaluation of some problems associated with clinical caries trials by computer simulation

Area of Science:

• Dental research
• Clinical trial methodology
• Epidemiology

Background:

• Current measures of caries experience in clinical trials, such as DMFS (decayed, missing, and filled surfaces), include components that do not accurately reflect active caries progression.
• Examiner errors, if below 10%, have a limited effect on trial outcomes, but larger errors can inflate variance.
• Certain components of DMFS, like SU (sound to decayed, missing, or filled) and UU (incipient to decayed, missing, or filled), are influenced by factors other than active caries or represent historical data.

Purpose of the Study:

• To evaluate the reliability of DMFS as a measure of caries experience in clinical trials.
• To propose and justify the use of an alternative index, the NCI (New Caries Index), for assessing caries activity in clinical trials.

Main Methods:

• Analysis of the components of DMFS (IU, SU, UU) and their contribution to overall caries experience.
• Evaluation of the impact of examiner errors on clinical trial outcomes.
• Assessment of the NCI (SI + IU) in relation to active caries stages.

Main Results:

• The DMFS index is deemed unjustified for measuring caries experience due to the inclusion of non-active caries components (SU, UU) and the typically small contribution of active caries (IU).
• Examiner errors exceeding 10% can significantly increase variance in clinical trial results.
• The NCI (New Caries Index), comprising SI (sound to incipient) and IU (incipient to decayed, missing, or filled), directly addresses the stage where cariostatic agents are expected to function.

Conclusions:

• The DMFS index is not a suitable measure for caries experience in clinical trials.
• The NCI (New Caries Index) offers a more accurate and advantageous approach to measuring caries activity and the effectiveness of cariostatic agents in clinical trials.