If your child has suffered an injury to one or more of the primary incisors you can expect the following reactions: 

The tooth might Change in colour. The tooth (teeth) will probably darken over a period of time, eventually turning quite dark. Usually, the color will be a charcoal gray, although it may be brown or yellow. The tooth will be returning to a color similar to how it appeared before the injury, but not quite as snow white. 

The tooth may also become loose. In this case the bone that supports the tooth has been expanded by the injury, which will make the tooth looser than normal. As the bone returns to the normal position, the tooth should also tighten up again. 

As with any injury, the normal reaction of the injured tissues (in this case, the gums and/or lips) will bleed and/or swell. A cold pack will help decrease the swelling the first day. From 2nd day apply a warm compress on the swollen area.

Fortunately, children do not usually suffer much pain from injuries to teeth. Occasionally there will be pain if the child tries to chew with the injured tooth. The child should have only soft food for a week after the injury.

You should watch for any of the following… 

• Change in any eating or sleeping habits 
• If your child’s normal eating habits change, particularly complaining when biting or chewing. Also note if your child is not sleeping.
• Increased swelling, looseness or pain 
• Gum Boils (This will appear on the gums in the area where the gums and lips meet. Gum boils look like a small blister on the gums.) 

If any of the ‘expected reactions’ become worse, the area should be re-examined by your dentist.

Canker sores (aphthous ulcers) are painful ulcers inside the mouth. They may occur under the tongue or on the inside linings of the cheeks and lips. They usually appear white, gray or pale yellow with a red border.  They are the most common type of mouth ulcer with at least 1 in 5 people developing aphthous mouth ulcers at some stage in their life. Women are affected more often than men.

Canker sores are not contagious and those of simple, small forms can heal within 10-14 days where multiple large sores may take 2 months to heal.

The exact cause of most canker sores is unknown. Stress or tissue injury is thought to be the cause of simple canker sores. Spicy food and citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries) can trigger an outbreak or make the problem worse. Sometimes a sharp tooth surface or ill-fitting dentures might also trigger canker sores. Hormonal changes and sometimes medications seem to be another factor in their development.
Some cases of complex canker sores are caused by an underlying health condition, such as an impaired immune system and gastrointestinal tract disease, such as Celiac disease and Crohn's disease, nutritional deficiency, such as vitamin B-12, zinc, folic acid, or iron. 

Treatments

In most cases, canker sores do not require any treatment. If a person already has an appearance, there are steps that can be taken to help relieve the pain or irritation and speed healing:

• Avoid acidic foods such as citrus fruits, or spicy foods that may aggravate the sore 
• If there is a vitamin deficiency (a doctor can test for this), take supplementation as prescribed
• Brush teeth gently and use a brush with soft bristles. 
• See a dentist if you have badly fitting dentures 
• If you suspect a medication is causing the ulcers, then a change may be advisable
• Use toothpaste and mouthwash that does not contain sodium lauryl sulphate
• For pain, topical medications such as Oragel applied directly on the sore or anti-inflammatory agents can be used in case of sever sores

For many natural remedies, please visit  the following website http://www.drweil.com/drw/u/ART02954/Canker-Sores.html

What causes my teeth to be sensitive? 

Tooth sensitivity occurs when the underlying layer of your teeth - the dentin - becomes exposed. Dentine contains little tunnels (tubules) that link to the nerves on the inside of the tooth. When dentine is exposed, these nerves are easily stimulated resulting in pain, especially to cold drinks, food, and air as well as physical pressure, heat, sweet and sour foods.

There are many factors that may lead to the development of tooth sensitivity such as brushing too hard, recession of the gums, cracked teeth or fillings, teeth grinding, tooth whitening products, acid erosion or cavities.

Toothbrush and/or toothpaste damage may be the most frequent cause of sensitivity of otherwise healthy teeth. Over time, brushing too hard or using a hard-bristled toothbrush can wear down enamel and cause the dentin to be exposed. It can also cause recession of the gums (the gum tissue pulls away from the teeth) where the roots get exposed.

What can dentists do about sensitive teeth? 

Check with your dentist to determine the cause of the sensitivity.

Depending on the cause, your dentist may be able to paint special fluoride varnishes onto the affected teeth. There are also other sensitivity products that can be used.

In cases of extreme sensitivity, your dentist can seal or put bonding around the neck of the tooth, to cover exposed dentine.

If you grind your teeth, ask your dentist about the possibility of having a mouth guard made to wear at night.

What can I do about sensitive teeth? To prevent further damage, brush your teeth gently and avoid abrasive toothpaste.

Desensitizing agents such as Sensodyne tooth paste work by blocking off the dentinal tubules, so that the nerves don’t get stimulated. They work a lot better by gently massaging the paste or gel into the sore spot with a finger. Do not rinse it off. It may take several weeks before the desired effect is achieved. When sensitivity has subsided then it can be used as regular tooth paste.

Using fluoride containing mouthwash also can help. Use it just before bed and do not rinse.