Cariology Lecture 9 Dietary Carbohydrates and Dental Caries

Nutritive sweeteners

Sweeteners that provide calories and can be metabolized for energy, such as sucrose, glucose, fructose, lactose, maltose, and sugar alcohols (polyols).

Non-nutritive sweeteners

High-intensity, low- or zero-calorie sweeteners that provide sweetness without fermentable carbohydrate (e.g., aspartame, saccharin, sucralose, acesulfame-K, stevia, monk fruit).

Cariogenic potential of sweeteners

Nutritive sweeteners are fermentable by bacteria and can cause acid production and caries; non-nutritive sweeteners are non-fermentable and non-cariogenic.

Sugar alcohols

They are nutritive but not acidogenic; xylitol may be cariostatic (inhibits S. mutans).

Factors influencing sweetener choice in food industry

Choice depends on sweetness, heat/pH stability, caloric content, texture, and cost.

Common foods with high sugar content

Soft drinks, candies, sweetened cereals, baked goods, fruit drinks, flavored yogurts, condiments.

Essential factors for caries formation

Tooth surface, cariogenic bacteria, and fermentable carbohydrate.

Most cariogenic carbohydrates

Refined, fermentable sugars—especially sucrose and processed starches.

Observational studies on sugar and caries

Sugar intake correlates positively with caries; frequency is more important than total intake.

Hopewood House study findings

Children on low-sugar lactovegetarian diets had fewer caries; caries increased when adopting a Western diet.

Vipeholm study findings

Sugar eaten between meals caused much more caries than sugar with meals; sticky sweets were worst.

Turku study findings

Replacing sucrose with xylitol reduced caries significantly; fructose substitution had smaller benefit.

Animal studies on caries

Effects of sugar are local (not systemic); frequency and concentration increase caries; germ-free animals do not develop caries.

Stephan curve

A graph showing plaque pH vs. time after sugar exposure—rapid drop below critical pH (≈5.0-5.5) followed by slow recovery.

Cariogenicity and the Stephan curve

Foods that cause deeper or longer pH drops are more cariogenic.

Carbohydrate form and caries risk

Sticky/retentive foods (cookies, chips) cling to teeth and prolong acid exposure; liquids clear faster.

Frequency of carbohydrate exposure and caries risk

Saliva

Buffers plaque acids, supplies minerals, and clears food debris; stimulated flow protects teeth.

Self-cleansing foods

Fibrous foods (raw vegetables, nuts, cheese) that stimulate saliva and help clean teeth.

Buffering agents

Chewy, protein- or fat-rich foods (cheese, peanuts) that boost saliva's neutralizing ability.

Clearance time

Time required for sugars to leave the mouth; longer clearance increases risk.

Sugar substitutes

Reduce fermentable substrate availability and prevent acid production.

Non-milk extrinsic sugars (NMES)

Sugars added or outside cell structure (e.g., added sugars, juices) that are more cariogenic.

Food labels

Show total/added sugars and ingredients, helping patients choose less cariogenic foods.

Sugar vs. sugars

'Sugar' often means sucrose; 'sugars' includes all mono- and disaccharides like glucose, fructose, lactose.

Refining starch

Processing breaks complex carbs into smaller fermentable units for bacteria.

Iowa Fluoride Study

Higher SSB intake increased caries; milk and water were protective; fluoride and brushing reduced risk.

Observational studies trends

Sugar intake and caries are linked; unrefined carbs protect short-term; frequency matters most.

Clinical studies findings

Sugar at meals causes slight caries increase; sugar between meals causes major increase; caries vanish with sugar removal.

Enamel slab and plaque pH studies

Fermentable sugars cause demineralization; non-fermentable sugars are neutral or protective; critical pH ≈5.0-5.5.

High-risk foods for caries

High sugar, processed starch, sticky foods, low in fat/calcium.

Protective foods against caries

High-fat dairy (cheese), nuts, xylitol-containing foods, fibrous vegetables.

Ultra-processed food review

High UPF intake increases caries risk by 71%.

Meal patterns influence on caries

Fewer, structured meals reduce acid exposures compared to frequent snacking.

SSBs and caries risk

Frequent acid attacks can override fluoride's protective effects.

Diet vs. regular sodas

Diet sodas are non-cariogenic but erosive; regular sodas are both cariogenic and erosive.

Link between sugar intake and ECC

Frequent sugar or SSB exposure in toddlers increases early childhood caries severity.

EBD principles in dentistry

Using evidence from studies to guide patient education and preventive care strategies.