Overview

• Principles of QLF

• The Equipment

• The Results

• Clinical Uses

• Questions and Demonstration

Why a New Diagnostic Method?

• Prevent cavitation– Spotting trouble early

• early lesions (white spots)• bacterial activity

– Follow trouble through time– Objective support for the prevention process

• Enhance the quality of oral care– Improve the quality of restorations and sealants– Improve, encourage and focus the quality of oral hygiene

Early Lesion Detection

E D

• Scattering properties of tooth tissue allow contrast enhancement

White Spot

Red Fluorescence Detection

E D

Pre-invasive Lesion Detection

QLF Contrast Enhancement

White Light QLF

Examples of Bacterial Activity

The System and The Software

PC

Light guide

Video camera

QLF system box

Dentistry: QLF-Scan, QLF-Pro

Longitudinal Monitoring

Caries Mapping

Before brushing Area = 30.6 mm2

ΔR = 51.8 %

Red Fluorescence: Quantification

RCutoff = 20%

clean

After Brushing Area = 9.6 mm2

ΔR = From 51.8% to 30.5 %

White Spot Lesion Exposed

Danger Zones: Bacterial Activity

Defective sealant.

Sealant applied over unprepared carious tooth

Red fluorescence indicating caries at the edges of a restoration.

The restoration was replaced, yet secondary caries remains.

Sealants Restorations Hidden Caries

Discolored fissure in a molar identified as ‘sensitive’. Note the red hue around the fissure.

When the fissure was opened, a dentinal lesion was found.

Use During Restorative Procedures

• Diagnose presence of secondary caries

• Check removal of bacterially affected tooth substance

Red fluorescence indicating bacterially affected caries at the edges of a restoration.

Corresponding radiograph: red arrows mark the radio-translucency underneath the restoration.

The restoration was replaced, yet secondary caries remains.

All pictures courtesy of Dr. R. Heinrich-Weltzien and Dr. J. Künisch,

Friedrich-Schiller University of Jena, Erfurt, Germany

Area = 2.2 mm2

ΔR = 32.4 %Area = 3.2 mm2

ΔR = 47.5 %Area = 0.7 mm2

ΔR = 25.3 %

Red Fluorescence: Caries ExcavationRCutoff = 20%

P. Sas 2003

Red Fluorescence: Sealants

No RF

Sound Sealant Leaking Sealant

R. Heinrich et al. 2001

Conclusions• Agreement with visual inspection (Radike)

– better sensitivity– very good specificity

• Quick patient assessment– Amount of initial lesions detected with QLF-Vision indicates

caries risk

• Longitudinal monitoring of lesions– follow de- and remineralization in time

• QLF-Vision is a reliable method for early lesion monitoring

QLF™

makes the

invisible

visible

Clinical Validation• 1994 Øgaard and ten Bosch: demonstration of lesion tracking by

measuring scattering properties

• 1995 de Josselin de Jong ea: Improvement of QLF system

• 1997 Al-Khateeb ea: detection of remin with QLF in weekly intervals consistent with microradiography

• 1998 Al-Khateen ea: QLF can be used to evaluate pre-invasive treatment

• 1998 Connersville study (IU):

– QLF appropriate for use on occlusal as well as buccal-lingual surfaces

– QLF is practical for large-scale clinical studies

– QLF detects 4-9 times as many lesions vs. visual inspection

– QLF validity for caries detection supported (ten Cate ea, 1999)

Clinical Validation

• 2001 Traneus ea: QLF is a sensitive method for longitudinal monitoring of incipient lesions on smooth surfaces

• Heinrich ea (to be published): QLF was able to separate groups of high-caries patients (33) that were given prophylaxis with or without the application of fluoride varnish, every 8 weeks for 6 months.

Clinical Validation in Progress• At IUPUI (Dr. George Stookey):

– 2-Year study to validate QLF for the detection of primary caries– 2-Year study to validate QLF for the detection of secondary caries– 18-Month study of QLF to monitor caries in orthodontic patients– 18-Month study of ability of QLF to detect differences in caries

rates in patients provided toothpastes with different concentrations of fluoride

• At Inspektor:– Correlation between red fluorescence and specific bacterial strains.– Clinical study on bracket related incipient caries