What are the considerations for a pregnant patient in the 3rd trimester who needs a dental filling?

Dental Filling in Third Trimester Pregnancy

Dental fillings can and should be performed safely during the third trimester of pregnancy using lidocaine with epinephrine as the local anesthetic, with no need to delay treatment until after delivery. 1, 2

Timing and Safety of Dental Treatment

• The third trimester is safe for all routine dental procedures including restorative work (fillings). 3, 2
• While the second trimester (weeks 17-28) is traditionally considered ideal for elective procedures, the third trimester poses no contraindication to necessary dental treatment. 3
• Emergency or urgent dental treatment should never be delayed regardless of trimester, as untreated dental disease poses greater risks to both mother and fetus than the treatment itself. 3

Local Anesthesia Selection

Lidocaine with epinephrine (1:100,000 or 1:200,000) is the anesthetic of choice for dental procedures during pregnancy. 1

Lidocaine Safety

• Lidocaine is safe throughout all trimesters of pregnancy when used in appropriate dental doses. 1, 2
• A prospective study of 210 pregnancies exposed to dental local anesthetics (including 112 in the first trimester) found no increased risk of major anomalies (4.8% vs 3.3% in controls, p=0.300). 2
• There was no difference in miscarriage rates, gestational age at delivery, or birth weight. 2

Epinephrine Considerations

• Small amounts of epinephrine added to local anesthesia are safe during pregnancy, including the third trimester. 1
• Epinephrine is FDA pregnancy category C, but when used in small dental volumes, the local vasoconstriction actually limits maternal blood levels and placental transfer of lidocaine. 1
• The benefits of epinephrine (prolonged anesthesia, reduced bleeding, decreased total anesthetic dose needed) outweigh theoretical risks when used in standard dental concentrations. 1
• Use concentrations of 1:100,000 or 1:200,000 for optimal vasoconstriction and anesthetic duration. 1

Patient Positioning

• Position the patient in a left lateral tilt or semi-reclined position to avoid supine hypotensive syndrome. 3
• In the third trimester, the gravid uterus can compress the inferior vena cava when the patient is fully supine, reducing venous return and causing maternal hypotension and decreased placental perfusion. 3
• Use a wedge or pillow under the right hip to maintain left lateral displacement of at least 15 degrees. 3

Radiographic Considerations

• Diagnostic dental radiographs can be performed if clinically necessary, even in the third trimester. 3, 2
• Use appropriate shielding with a lead apron that covers the abdomen and thyroid. 3
• Bite-wing radiographs were the most common type used in the safety study (44% of exposed pregnancies). 2
• The radiation exposure from dental radiographs is minimal and does not approach levels associated with fetal harm. 3

Pain Management and Antibiotics

Analgesics

• Acetaminophen (paracetamol) is the analgesic of choice during pregnancy. 3
• Avoid NSAIDs, especially in the third trimester, as they can cause premature closure of the ductus arteriosus. 3

Antibiotics (if infection present)

• Amoxicillin, ampicillin, and certain cephalosporins are safe throughout pregnancy. 3
• Some macrolides (excluding clarithromycin) can be used if penicillin allergy exists. 3

Thromboembolism Prophylaxis

• Outpatients with active inflammatory conditions (including dental infections) should receive VTE prophylaxis during the third trimester unless contraindicated. 1
• This is particularly relevant if the patient requires hospitalization for severe dental infection. 1

Common Pitfalls to Avoid

• Do not delay necessary dental treatment due to unfounded concerns about safety. Many dentists remain reluctant to treat pregnant patients despite strong evidence of safety. 4, 3
• Do not avoid epinephrine-containing anesthetics. The addition of epinephrine in small dental doses is safe and provides superior anesthesia. 1
• Do not position the patient flat supine for prolonged periods. This can cause aortocaval compression syndrome in the third trimester. 3
• Do not prescribe NSAIDs for post-operative pain. Use acetaminophen instead. 3

Procedure-Specific Considerations

For the dental filling procedure specifically:

• Standard restorative techniques can be used without modification. 3, 2
• Endodontic treatment (43%), tooth extraction (31%), and tooth restoration (21%) were all performed safely in the prospective cohort study. 2
• Most patients (63%) required no additional medications beyond local anesthesia. 2