Cavity Fillings: Expectations, Types & Aftercare

Dr Advocate Avatar IconUpdated: August 12, 2022
By: Dr. Advocate

According to the American Dental Association (ADA), 91% of Americans over 20 have had cavities at some point in their lives, and 27% of people over 20 have untreated cavities! If you’ve ever had a cavity, you know how uncomfortable it can be. Regular dental visits can uncover cavities before they become a pain. If a cavity is visualized radiographically or during your oral exam, the tooth will need a filling to replace the tooth structure after the cavity is removed. There are many filling materials, and each is unique in function, composition, and utility.

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What type of filling material is best?

Fillings are essential to preserve the remaining tooth structure and prevent tooth fracture. Some fillings are technique sensitive (composite, inlays, onlays), while others are used when isolation is difficult (amalgam) or fluoride release is desired (glass ionomer). Isolation refers to keeping the tooth clean and free from saliva contamination during the filling process.

At times, adequate isolation is challenging; however, it’s essential for therapeutic success and longevity. Your dentist will review your options with you before treatment. But, first, let’s compare the pros and cons of the most common filling materials they’ll use.

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Amalgam (“silver filling”)


  • Inexpensive
  • Ideal for larger fillings
  • Relatively quick application
  • Used when isolation is difficult
  • Mechanically locks into tooth
  • Long track record


  • Unsightly
  • Releases mercury
  • Prone to fracture
  • Unable to bond to tooth

Composite resin (“tooth-colored”)


  • Esthetically pleasing
  • Polishes well
  • Simple to repair
  • Multiple shades is possible
  • Chemically bonds to tooth


  • Highly technique sensitive
  • AApplication process is extensive
  • Saliva isolation is paramount
  • Light contact with adjacent teeth



  • Esthetically pleasing
  • Ideal contact with adjacent teeth
  • Preserves tooth structure


  • Expensive
  • Technique sensitive
  • Restoration fracture is possible
  • Scanning unit is required

Glass ionomer


  • Quick application process
  • Releases fluoride over time
  • Ideal when isolation is difficult
  • Chemically adheres to tooth structure


  • Prone to wear
  • Weaker bond strength
  • Longevity is guarded
  • Challenging to manipulate

What are the steps involved?

First, the clinician will carefully remove the decayed tooth structure. If the cavity is superficial, the clinician may remove the cavity without using an anesthetic, which is ideal for many reasons, including verifying the bite after correctly completing the restoration. If anesthesia is necessary, the clinician will apply topical benzocaine, followed by an anesthetic.

Teeth fillings | Molar tooth fissure restoration with filling| Medically accurate illustration.After adequate anesthesia is achieved, the clinician will remove the cavity using a high-speed drill, followed by a slow-speed drill. The slow-speed drill removes decay less aggressively to prevent trauma to the underlying pulp tissue. Also, the clinician will have better control in removing the cavity without exposing the nerve.

If the cavity is near the nerve, the clinician may apply medication to prevent postoperative pain and future complications. This procedure is referred to as an indirect pulp cap. The dentist may use a direct pulp cap if the nerve is minimally exposed during decay removal. A direct pulp cap technique is successful if isolation is maintained and minor trauma.

After the cavity is removed, the area is irrigated and isolated to prepare the surface for proper bonding. If the clinician uses amalgam or glass ionomer, the materials are prepared, applied, and allowed to set. If a composite resin is used, the area in the tooth is acid-etched, the dentist will apply the bond, and the dentist will use a light to set the material. Then, the composite resin is layered in place and cured.

The clinician will often overapply the material and polish it back to an ideal size and shape. Finally, the bite and interproximal contact (contact with adjacent teeth) will be evaluated and adjusted. Your clinician will ask you to bite down and grind your teeth adequately so high spots can be visualized and fixed before leaving the clinic.

Aftercare instructions

Upon completion, the dentist will advise you to avoid eating until the anesthesia has worn off to prevent unnecessary tissue trauma. The numbness should subside after a few hours. At that time, it’s normal for your teeth to be sore and tender. It’s encouraged to lightly massage your jaw muscles and apply a cold pack if needed. Also, your clinician may encourage you to take an NSAID to help with the healing process.

Sensitivity with the restoration is possible for 1-2 weeks; however, if you’re still having discomfort, be sure to contact your clinician. You may be biting high on the restoration, and adjustments will be needed to eliminate the source of pain. If dental pain begins to wake you up at night or the toothaches uncontrollably, you may have irreversible pulpitis, and a root canal may be recommended.


Composite resin fillings are primarily used because of their versatility and availability. Inlays and onlays are best suited when the preparation size is too large for a predictable filling. If the clinician is equipped with a scanning unit, they’ll be able to design, fabricate and deliver the restoration within a few hours. A full-coverage crown is avoided in this scenario, and the tooth structure is preserved.

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Common questions

  1. How long do fillings last? On average, fillings last 10-20 years. Amalgam fillings tend to last longer than composite fillings because they don’t expand and contract with temperature changes like composite fillings do, which leads to marginal leakage, recurrent decay, and failure. Alternatively, amalgam fillings are more prone to fracture or cause teeth to crack because they aren’t bonded to the tooth.
  2. Should I have my amalgam fillings replaced? If there are cracks in the surrounding tooth structure or the filling is separating from the tooth, then yes. Some patients desire composite fillings for esthetic reasons. If an existing filling is removed and replaced, the hole becomes more significant, leading to a higher likelihood of tooth fracture.
  3. Why are my fillings sensitive? Composite fillings are sensitive to hot and cold because they expand and contract with temperature changes which strain tooth structure, which leads to hypersensitivity. In addition, leakage (gaps under filling) will allow liquids to stimulate sensitive areas.
  4. What does the blue light do after the clinician applies the filling? This UV light solidifies the bond and composite material. Clinicians and patients should never stare directly into the light.

Final thoughts

Dental fillings are essential to repair and replace missing tooth structures. Have you recently been diagnosed with needing a filling or crown? Are you confused about the diagnosis or treatment options? My Dental Advocate’s team of board-certified dentists can provide a second opinion on your planned treatment. We look forward to bringing you peace of mind by verifying your treatment plan, suggesting an alternative, or answering your questions.

Dr Advocate Avatar IconAbout the Author

Dr. Advocate is an actual board-certified dentist with clinical practice experience and a mission to provide accurate dental patient education. He believes everyone should access easy-to-read dental resources presented in layman’s terms with relevant, up-to-date dental research and insight to improve their oral health.