Smoking and Its Influence on Wound Healing: An Overview

Introduction

Wound healing is a complex process that can be divided into at least three continuous, but overlapping stages. It is divided into -

• The inflammatory phase.
• The phase of tissue proliferation.
• The phase of tissue repair and remodeling.

Wound healing is a highly coordinated process that involves a complex interdependence of various cell types, cytokines, and growth factors at the site of injury. This means that normal tissue oxygen pressures are important in all the stages of repair including movement of cells to the wound site, fighting off bacteria, and formation of new tissue collagen. The healing process is a continuous and dynamic process that can be halted at any stage by tissue hypoxia. Hypoxia has also been known to enhance the likelihood of surgical patients developing wound infections partly because of the neutrophil’s reduced bactericidal effectiveness.

How Is Smoking and Wound Healing Inter-Related?

Tissue hypoxia is considered as a primary factor through which smoking impairs the process of acute wound healing. The negative impact of smoking on tissue oxygenation has been shown even after smoking a single cigarette regardless of the previous smoking history. Moreover, Jensen and colleagues 42 stated that “pack-per-day” smokers are in a state of tissue hypoxia for a certain period of the day.

Cigarette smoke has been described to have more than 4000 toxic compounds in it. The main toxins that hinder the wound healing process are nicotine and gases such as carbon monoxide and hydrogen cyanide. The precise pathways by which tissues heal through delay are not fully understood; however, all have been demonstrated to negatively affect oxygen delivery to tissues.

What Is Extraction?

Extraction or exodontia is the procedure of "painless removal of the whole tooth or root with minimum trauma to the investing tissues (hard and soft) so that the wound heals uneventfully".

What Are the Different Techniques Used for Dental Extractions?

1. Intra-alveolar extraction.
2. Trans-alveolar extraction.
3. Stobie technique.

1. Intra-Alveolar Extraction or Traditional or Conventional Extraction:

• Removal of a tooth or root by using specific dental forceps and elevators.
• This method cannot be used in root deformities, hypercementosis, grossly decayed crowns or roots, brittle teeth or roots, or endodontically treated teeth or roots.
• It is also called simple extraction or closed method of extraction.

2. Transalveolar Extraction:

• Carried out by planning surgical flap technique with alveolar bone removal and tooth sectioning of a tooth or root.
• It is also called open method for extraction or complex/complicated extraction procedure.

3. Stobie Technique:

• Extraction of multiple lower front teeth using dental elevator for tooth extractions.

What Are the Factors That Influence Wound Healing?

Factors influencing wound healing include:

• Poor oral hygiene.
• Spicy food intake.
• Infection.
• Smoking.
• Old age.
• Anemia.
• Vitamin C deficiency.
• Diabetes.
• Hepatitis.
• Prolonged steroid intake.

How Does Smoking Affect Wound Healing?

Cause - Smoking causes negative pressure inside the mouth, dislodges the clot, and other complications.

• Tobacco smoke and nicotine would delay wound healing.
• Patients should limit or stop smoking after teeth removal till healing.
• Smoking increases the risk of dry sockets.

What Is a Dry Socket?

Dry socket or alveolar osteitis is delayed healing but without infection. It involves part or whole of the walls of the socket or the lamina dura.

Etiology:

• Not clear.
• Due to trauma and infection together.
• They cause inflammation of bone marrow spaces of the alveolar bone.
• That liberates tissue activators which then convert plasminogen in the blood clot to plasmin.
• This dissolves the blood clot and releases kinins from the kininogen which is present in the blood clot.
• The final result is the dissolution of the blood clot which leads to severe pain.

Predisposition Factors:

• Infection of the socket occurs either before, during, or after the extraction.
• Trauma following the use of excessive force during extraction.
• However, it may also occur following very easy extractions.
• Vasoconstrictors: Many authorities feel that vasoconstrictors used in LA (local anesthesia) solution may predispose to dry socket, by interfering with the blood supply of bone and they also point out that the condition occurs more frequently under local anesthesia than general anesthesia. Thus vasoconstrictors act as a contributing factor in developing dry sockets.
• Lower jaw teeth show a higher incidence of dry sockets than upper jaw teeth, as the lower jaw has much more dense bone and is less vascular than the upper jaw.
• Gravity: lower teeth sockets become contaminated with food debris.
• Existence of Systemic Etiological Factor: Increased titer of the fibrinolytic substances has been seen in the alveolar bone of patients afflicted with dry sockets.
• Bacteriological Origin: Some bacteria are known to possess fibrinolytic activity. It is caused by Treponema denticola which may have a role in the genesis of dry socket. Pregnant women and those taking oral contraceptives appear to be more susceptible than others.

Symptoms:

• They are usually seen three to four days after tooth removal.
• Severe acute pain is felt.
• No signs of swelling, redness, or fever were seen.
• A bony surface is seen on the site of the removed tooth.
• Seen mostly in lower teeth removal.

How to Prevent Dry Socket?

The following measures should be employed to prevent dry sockets:

• Scaling of the teeth and any gingival inflammation should be treated before extraction.
• A minimum amount of local anesthetic solution necessary for producing analgesia should be administered.
• Teeth should be removed in the least traumatic manner possible.
• Prophylactic antibiotics especially Metronidazole from the day of extraction for three to four days reduce the incidence of dry socket.
• It also provides relief from pain if given in large doses for five days.
• Wound debridement.
• Nerve blocks are preferred to local anesthesia infiltration.

What Is the Treatment of Dry Sockets?

It is not a progressive disease, so the goals are to relieve pain and speed up resolution.

• Symptomatic treatment is provided by the dentist.
• Irrigation of debris and debridement of the socket with warm normal saline and all degenerating blood clots are removed.
• Sharp bony margins are removed with either rongeur forceps or smoothened with a bone file. Medicated dressing like iodoform gauze or cotton wool composed of zinc oxide eugenol is placed inside the socket.
• It should be placed loosely and not tightly; as it may become hard later and become difficult to remove.
• The medicated dressing is composed of eugenol, Balsam of Peru, chlorobutanol, and Benzocaine.
• Dressings should be changed in the following order: after the first 24 hours, then every other day, and finally every three to four days for more than two weeks.
• Broad-spectrum antibiotics should be prescribed.
• Analgesics are also prescribed.
• Hot saline mouth rinses are advised.
• Regular follow-ups are necessary.

Chemical Cauterization:

If pain persists, the exposed bare bone is treated by chemical cauterization. The procedure for chemical cauterization is listed below -

• Isolation and drying of dry socket.
• Application of a small quantity of carbolized resin on the body walls of the socket.
• Zinc oxide eugenol cotton wool is placed in situ for three days.
• The dressing relieves pain but delays healing.
• Alternatively, whitehead’s varnish on a piece of ribbon gauze can also be used and left in situ for two to three weeks.
• It is not very effective in controlling pain.
• On removal of the medicated dressing pack the socket can be seen granulating.

Conclusion

Several studies show smokers have an increased risk of pain and delay in wound healing than nonsmokers after tooth removal. Patients are advised to follow postoperative instructions properly and limit or stop smoking till wound healing. If someone continues to have persistent pain after three to four days of extraction, they should consult a dentist. “Prevention is better than cure.”