Lecture 21: GI System and Oral Health

Obesity

BMI >30

High waist circumference

Comorbidities of Obesity

Type II Diabetes

Hypertension

Cardiovascular disease

Cancer

Statistical associations between obesity and periodontal disease

Typically probing pocket depth

Clinical attachment loss

Bleeding on probing

Overall higher probability of perio disease in obese people compared to normal weights

Xerostomia and Obesity

Saliva is the main defense against acid in the oral cavity

Inflammation disrupts salivary acinar glands, which reduces secretions and alters the composition

Inflammation disrupts PNS salivary stimulation

Comorbid insulin resistance leads to microvascular blood flow, disrupted by AGEs

Impaired nutrient and O2 delivery to salivary glands

Comorbid sleep apnea and chronic mouth breathing

Polypharmacy

Caries and Obesity

Diet with fermentable sugars leads to acidic biofilm and microenvironment

Low bicarb content in saliva and reduced saliva in general

Inflammation and insulin sensitivity

How does saliva neutralize acid?

Bicarb

Physical clearance

Ions are buffers that bind H+

How does saliva reduce bacteria?

Mucin

Physical clearance

Antibodies and anti-microbials

Oral consequences of GERD

Dental erosion

Dental attrition

PPIs

Dental erosion

Chemical disillusion of enamel independent of bacteria

Hydroxyapatite crystals are damaged by low pH

More common on palatal surfaces of maxillary teeth

Increased tooth sensitivity and pain with dentin exposure is secondary to erosion

Dental attrition

Mechanical wear from tooth-to-tooth contact

PPIs for GERD

Most prescribed drug treatment

Many pts will take these

Xerostomia

Increased pH

Oral candidiasis

Bariatric surgeries

Re-route the GI tract to alter metabolism

Physically restrict food intake

Reduce nutrient absorption

Oral consequence of bariatric surgery

Increased vomiting and GERD leads to erosion

Increased caries from more frequent meals

Vitamin B12 deficiencies and altered nutrient absorption

Delayed wound healing

Vitamin B12 deficiency and gastric bypass

Gastric rerouting and stomach loss leads to reduced parietal cells and intrinsic factor

Glossitis (beefy red tongue)

Glossitis and vitamin B12

B12 is needed for DNA synthesis with folate in high-turnover cells like mucosa

Reduced proliferation leads to atrophy

Red, patchy, thin epithelium, painful or numb, inflamed

Delayed wound healing and bariatric surgery

Gastric rerouting reduces acid secretion, pepsin, and protein breakdown

Bile and bicarb are introduced later since the duodenum is bypassed, reducing protein breakdown and fat absorption

Effects of reduced protein breakdown

Poor proliferation, collagen synthesis, angiogenesis, and cell migration

Delayed healing

Post-procedure ulcers

Incretins

Glucose-dependent insulinotropic peptide (GIP)

Glucagon-like peptide 1 (GLP-1)

Site of GIP

Duodenal K cells

Site of GLP-1

Ileal L-cells

What does GLP-1 therapy do?

Increases insulin secretion

Slows down gastric motility

Responsible for most of the post-prandial insulin response

Oral glucose load produces a greater insulin response compared to IV

How is GLP-1 used therapeutically?

Human GLP-1 has a short half-life

Mimetic and receptor agonists prolong the GLP-1 effect

Prolonged insulin release and gastric delay

How does GLP-1 affect dentistry?

12-15% of adults reported using the therapy in 2025

Can cause hypoglycemia

Can reduce hydration

Can cause gastroparesis and vomiting

Could cause inaccurate history and reporting if pt does not admit use

Inflammatory bowel disease

Chron’s or UC

Diagnosed based on symptoms, site, and histopathology

Oral consequences of inflammatory bowel disease

Affects up to 50% of IBD pts

Enlarged lips, ulcers, cobblestoning

Caries, infection, and perio disease

Malnutrition

Immunosuppressants

Oral consequences of immunosuppressants

Increased risk of infection

Delayed wound healing

Some bleeding risks

Risk for alveolar bone loss

DNA mutations

Active oncogenes

Suppress tumor-suppressor genes

Abnormal proliferation that leads to normal stratification and barriers often involves what?

Metaplasia

Dysplasia

Carcinoma

Metaplasia

Replacement of cell type, adaption to stress

Dysplasia

Abnormal growth of abnormal cells

Carcinoma

Malignant invasion

Cancer pathophysiology

DNA mutations

Abnormal proliferation

Inflammation

Angiogenesis

What do oral tissues depend on?

Lost of epithelial turnover

Enough vascular support

Continuous protein and micronutrient availability

Oral cancer pathophysiology

DNA mutations in squamous cells (90% is oral squamous cell carcinoma)

Tongues gingiva, floor of mouth

Alcohol, tobacco, and HPV are major risks

Clinical presentation of oral cancer

Non-healing lesions

Chronic sore tongue

Red, white, or mixed patches

What do oral squamous cells normally tolerate?

Mechanical stress

Chemical exposure

Microbes

Adaptive metaplasia doesn’t usually occur, only dysplasia with chronic insults

Esophageal cancer pathophysiology

Chronic irritation of the esophageal lining

Squamous cells carcinoma in upper/mid esophagus

Adenocarcinoma in the lower esophagus

Squamous cells are replaced with gastric-like columnar cells

Clinical presentation of esophageal cancer

Difficulty/painful swallowing

Unintentional weight loss

Long term nutrient deficiencies due to weight loss and reduced intake

What can cause difficulty swallowing?

Fibrotic responses in tissues that increase stiffness

Invasive growth

Pathophysiology of stomach cancer

Mainly gastric adenocarcinoma affects gastric pits/glads

Chronic inflammation leads to gastritis, metaplasia (reduced acid, IF, and loss of normal function)

Metaplasia leads to dysplasia (breakdown of control, abnormal cell cycles, less DNA repair)

Parietal cell gastric adenocarcinoma

Acid

Intrinsic factor

Chief cell gastric adenocarcinoma

Pepsinogen

ECL gastric adenocarcinoma

Histamine for acid

Goblet cells for adenocarcinoma

Mucous

Clinical presentation of stomach cancer

Early stages may be asymptomatic or vague

Protein and micronutrient deficiencies (vit B12)

Oral consequence of GI cancer

Nutritional deficiencies

Cancer therapies (impaired mucosal renewal)

Xerostomia

Altered taste