单项选择题

Wisdom Teeth Wisdom teeth are the last teeth to erupt. This occurs usually between the ages of 17 and 25. There remains a great deal of controversy regarding whether or not these teeth need to be removed. It is generally suggested that teeth that remain completely buried or un-erupted in a normal position are unlikely to cause harm. However, a tooth may become impacted due to lack of space and its eruption is therefore prevented by gum (齿龈), bone, another tooth or all three. If these impacted teeth are in an abnormal position, their potential for harm should be assessed. What are the Indications for Removing Wisdom Teeth Wisdom teeth generally cause problems when they erupt partially through the gum. The most common reasons for removing them are: Decay Saliva(唾液), bacteria and food particles can collect around an impacted wisdom tooth, causing it, or the next tooth to decay. It is very difficult to remove such decay. Pain and infection will usually follow. Gum Infection When a wisdom tooth is partially erupted, food and bacteria collect under the gum causing a local infection. This may result in bad breath, pain, and swelling. The infection can spread to involve the cheek and neck. Once the initial episode occurs, each subsequent attack becomes more frequent and more severe. Pressure Pain Pain may also come from the pressure of the erupting wisdom tooth against other teeth. In some cases this pressure may cause the erosion of these teeth. When is the Best Time to Have Wisdom Teeth Removed It is now recommended by specialists that impacted wisdom teeth be removed between the ages of 14 and 22 years whether they are causing problems or not. Surgery is technically easier and patients recover much more quickly when they are younger. What is a relatively minor operation at 20 can become quite difficult in patients over 40. Also the risk of complications increases with age, and the healing process is slower. Should a Wisdom Tooth be Removed When an Acute Infection is Present Generally, no. Surgery in the presence of infection can cause infection to spread and become more serious. Firstly, the infection must be controlled by local oral hygiene (卫生) and antibiotics (抗生素). The Pro’s and Con’s of Wisdom Tooth Removal Some Pro’s of Removing a Wisdom Tooth: Wisdom teeth may be hard to access with your toothbrush. Over time, the accumulation of bacteria, sugars and acids may cause a cavity to form in the tooth. If it is not restored with a filling, the cavity(洞) may spread and destroy more tooth structure causing severe consequences to the tooth and surrounding supportive structures. Due to the difficulty of keeping these teeth clean with your daily home care, bacteria and food debris remaining on the wisdom teeth may present a foul smell — causing bad breath. A wisdom tooth that is still under the gums in a horizontal position (rather than a vertical position) may exert pressure to the surrounding teeth, causing crowding and crooked teeth. This also may occur if there is not enough space in the mouth for the wisdom tooth. This may warrant braces to repair the damage. Some Con’s of Removing the Wisdom Teeth: Depending on the size shape and position of the tooth, removal can vary from a simple extraction to a more complex extraction. With a simple extraction, there is usually little swelling and/or bleeding. More complex extraction will require special treatment which may result in more bruising, swelling and bleeding. However, your dental professional will provide you with post treatment instructions to minimize these side effects. Following an extraction, a condition called “dry socket” may occur. If the blood clot (凝结) that formed in the extraction area becomes removed, it exposes the underlying bone. This condition is very painful, but resolves after a few days. It is preventable by following the post treatment instructions provided by your dental professional. The longer you wait and the older you get, there is the potential for more problems to occur. This is because as you get older, the bone surrounding the tooth becomes more dense, making the tooth more difficult to remove. The healing process may also be slower. Post Operative Care: Do Not Disturb the Wound In doing so you may invite irritation, infection and/or bleeding. Chew on the opposite side for the first 24 hours. Do Not Smoke for 12 Hours Smoking will promote bleeding and interfere with healing. Do Not Spit or Suck Through a Straw This will promote bleeding and may remove the blood clot, which could result in a dry socket. Control of Bleeding If the area is not closed with stitches, a pressure pack made of folded sterile (消毒的) gauze (纱布) pads will be placed over the socket. It is important that this pack stay in place to control bleeding and to encourage clot formation. The gauze is usually kept in place for 30 minutes. If the bleeding has not stopped once the original pack is removed, place a new gauze pad over the extraction site. Control of Swelling After surgery, some swelling is to be expected. This can be controlled through the use of cold packs, which slow the circulation. A cold pack is usually placed at the site of swelling during the first 24 hours in a cycle of 20 minutes on and 20 minutes off. After the first 24 hours, it is advisable to rinse (漱口) with warm saltwater every two hours to promote healing, (one teaspoon of salt to eight ounces of warm water). Medication for Pain Control Pills such as Aspirin can be used to control minor discomfort following oral surgery. Stronger medicines may be prescribed by the dentist if the patient is in extreme discomfort. Diet and Nutrition A soft diet may be prescribed for the patient for a few days following surgery. Following the removal of your wisdom teeth it is important that you call your dentist if any unusual bleeding, swelling or pain occurs. The first 6-8 hours after the extraction are typically the worst, but are manageable with ice packs and non-prescription pain medication. You should also plan to see your dentist approximately one week later to ensure everything is healing well. It is very important to talk to your dentist about extraction procedure, risks, possible complications and outcomes of the removal of these teeth. The actual extraction may be done by a dentist or it may be referred to an oral surgeon, who is a specialist. This decision is based on the dentist’s preference and the unique features of each individual case. If you are unsure about whether or not to proceed with the treatment suggested by your dental professional, it is a good idea to get a second opinion. If you decide after consulting with a dentist not to have any teeth extracted, they should be monitored at every dental visit. If there is an infection, the first thing to do is to stop it before get the wisdom tooth removed.