Oral Hygiene Tests - SBI and API

Sulcus bleeding index (SBI) and approximate plaque index (API) are tested at every appointment. The results are used to reflect the patient's progress of oral hygiene and overall progress. Typically SBI is performed first, and then API is performed secondly. This is because the gel of the API may stay on making it confusing to detect for bleeding.

Sulcus Bleeding Index (SBI)

1) Rinse to remove any food debris and dry the teeth.

2) Insert ball of WHO probe into the gingival sulcus at midline and sweep towards the interproximal until you reach the peak of the interdental papilla distally. However, do not sweep or count the inter proximal areas between central incisors or the 8s.

• Quadrant 1 buccal: sit at 8 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 2 lingual: sit at 1 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 3 buccal: sit at 10 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 4 lingual: sit at 1 for posterior teeth and move towards 12 for anterior teeth.

3) Wait 10 – 20 seconds, observe the interproximal areas, record as + for bleeding and – for not bleeding. Measure the number of bleeding sites.

5) Calculate the percentage of bleeding sites over the total number of reading point.

One tooth missing: space open and restored by bridge = no change in reading points

One tooth missing: space closed by orthodontic treatment = -1 reading point

Two teeth missing: space still open - restored by bridge or partial denture = -1 reading point

Three teeth missing: space still open - restored by bridge or partial denture = -2 reading points

6) Make a comment on patient's overall oral hygiene.

• Insufficient oral hygiene (>25%)

• Good oral hygiene (less than or equal to 25%)

• Very good oral hygiene (less than or equal to 15%)

Review Questions on SBI

How often do you perform SBI?

At every visit.

What does SBI stand for?

Sulcus bleeding index.

Where do you probe for SBI?

Start at the 7’s from the midline of the tooth and sweep with WHO probe to the distal and then midline to mesial aspect.

What are the steps of SBI?

Wash, rinse, dry, probe

What are you reading?

Interpapillary bleeding

What does WHO stand for?

World Health Organisation

What are the surfaces you need to probe for SBI?

Buccal of quadrants 1 and 3, lingual of quadrants 2 and 4

You have a tooth with 43, 44, 45 missing. Replaced 43 and 45 with 2 implants and placed a bridge i. Have you lost any reading points?

No

Same Scenario as above but done orthodontic treatment to close the gap. Then?

Loose 1 reading point

Apical Plaque Index

1) Rinse to remove any food debris and dry the teeth.

2) Micro-brush the disclosing agent called GC tricolour gel on the interproximal contact areas of teeth except between the central incisors.

• Quadrant 1 lingual: sit at 1 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 2 buccal: sit at 1 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 3 lingual: sit at 10 for posterior teeth and move towards 12 for anterior teeth

• Quadrant 4 lingual: sit at 1 for posterior teeth and move towards 12 for anterior teeth.

3) Rinse the tricolour gel and dry the area.

4) Record all blue stained tooth surfaces as positive reading points.

If unsure, use the WHO probe to attempt to remove any plaque from the contact areas.

• Pink: Immature biofilm and less than 24 hours old

• Dark blue: 48+ hours old plaque

• Light blue: High risk, acidic biofilm with pH <4.5 at risk of caries and more than 72 hours old

4) Calculate the percentage of positive reading points.

5) Make an assessment on the overall oral hygiene

• Insufficient oral hygiene (>35%)

• Good oral hygiene (less than or equal to 35%)

• Very good oral hygiene (less than or equal to 25%)

What does API stand for?

Approximate Plaque Index

How often do you need to perform API?

At every visit.

What is the range for API ?

Very Good 25% and Good 35%

What do the colours of the tricolour gel mean?

A. What does pink indicate? Less than 24hr - immature biofilm

B What does purple indicate? 48hr - haven’t brushed for a day

C What does light blue indicate? - More than 72hr and is acidic.pH 4.5 -> indicates a potential for caries

D. If you have light blue does this change your management? - Remove plaque and professional prophylaxis; fluoride treatment- to remineralise the area; OHI; Lifestyle & Dietary intervention

Where do you apply the TC Tricolour gel?

Interdental regions

What are the steps of API?

Wash, Rinse, Dry, Apply. Wash, Rinse, Dry, Read

In patients with low SBI and high API, what might be some of the reasons?

The patient forgot to brush before they came

It has been a while since they brushed last but usually have good OH

Smokers can have reduced vascularity

Drug taking (sugar drugs, hypertensive medications)

Name another disclosing agent that can be used for API?

Erythrosine (red colour only)

Why do you perform SBI first and API second

In the presence of significant gingival inflammation (blood) can prevent an accurate API score.

Px has API 25% but SBI 60-70%. Why?

They brushed very well on the day but in general don’t have good OH , as they have gingival inflammation; Blood thinners meds (aspirin, warfarin), Diabetes, Hormonal (pregnancy), haemophilia, systemic illness, inflammatory response is hyperactive

Why do we wash before API?

Remove any loose plaque or material alba.

Presentation of Results