Dentine exposure & opening of dentine tubules

Due to:

• Caries.
• fractured tooth.
• marginally defective restoration.
• cement failure.
• gingival recession, attrition, abrasion, erosion.

Previously

http://www.becomedentist.com/2008/12/diagnosis-for-pulp-disease/

Crown is restorations of teeth using materials that fabricated indirect in the lab  which cemented into place.

Traditionally, the teeth to be crowned are prepared by a dentist and records are given to a dental technician to fabricate the crown or bridge, which can then be inserted at another dental appointment. The main advantages of the indirect method of tooth restoration include:

* fabrication of the restoration without the need for having the patient in the chair
* the utilization of materials that require special fabrication methods, such as casting
* the use of materials that require intense heat to be processed into a restoration, such as gold and porcelain.

The restorative materials used in indirect restorations possess superior mechanical properties than do the materials used for direct methods of tooth restoration, and thus produce a restoration of much higher quality.

As new technology and material chemistry has evolved, computers are increasingly becoming a part of crown and bridge fabrication, such as in CAD/CAM technology.

Details is here:

http://en.wikipedia.org/wiki/Crown_(dentistry)

Teeth must be cut until its have retention from tooth surface and cement.

They are shoulder and syamfer margin.

For anterior teeth incisor shoulder 1-1.5 mm is trim

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Margin
A palatal view of a maxillary premolar during a crown lengthening procedure. This procedure is being performed because the height of the crown preparation is too short to obtain adequate retention but the minimum of 3 mm to allow for biologic width have already been realized.

The most coronal position of untouched tooth structure (that is, the continual line of original, undrilled tooth structure at or near the gum line) is referred to as the margin. This margin will be the future continual line of tooth-to-restoration contact, and should be a smooth, well-defined delineation so that the restoration, no matter how it is fabricated, can be properly adapted and not allow for any openings visible to the naked eye, however slight. An acceptable distance from tooth margin to restoration margin is anywhere from 40-100 ?m. However, the R.V. Tucker method of gold inlay and onlay restoration produces tooth-to-restoration adaptation of potentially only 2 ?m, confirmed by scanning electron microscopy; this is less than the diameter of a single bacterium.

Naturally, the tooth-to-restoration margin is an unsightly thing to have exposed on the visible surface of a tooth when the tooth exists in the aesthetic zone of the smile. In these areas, the dentist would like to place the margin as far apical (towards the root tip of the tooth) as possible, even below the gum line. While there is no issue, per se, with placing the margin at the gumline, problems may arise when placing the margin too subgingivally (below the gumline). First, there might be issues in terms of capturing the margin in an impression to make the stone model of the prepared tooth (see stone model replication of tooth in photographs, above). Secondly, there is the seriously important issue of biologic width. Biologic width is the mandatory distance to be left between the height of the alveolar bone and the margin of the restoration, and if this distance is violated because the margin is placed too subgingivally, serious repercussions may follow. In situations where the margin cannot be placed apically enough to provide for proper retention of the prosthetic crown on the prepared tooth structure, the tooth or teeth involved should undergo a crown lengthening procedure.
The natural tooth’s crown (A) meets the root (B) at the cementoenamel junction, and it is roughly at this point that the gingival attachment begins at the base of the gingival sulcus (G). The margin of the prosthetic crown may not violate the 2 mm of biologic width from the base of this sulcus to the height of the alveolar bone (C) if complications are to be avoided.

There are a number of different types of margins that can be placed for restoration with a crown. There is the chamfer, which is popular with full gold restorations, which effectively removed the smallest amount of tooth structure. There is also a shoulder, which, while removing slightly more tooth structure, serves to allow for a thickness of the restoration material, necessary when applying porcelain to a PFM coping or when restoring with an all-ceramic crown (see below for elaboration on various types of crowns and their materials). When using a shoulder preparation, the dentist is urged to add a bevel; the shoulder-bevel margin serves to effectively decrease the tooth-to-restoration distance upon final cementation of the restoration.

Why Is a Dental Crown Needed?

A dental crown may be needed in the following situations:

1. To protect a weak tooth (for instance, from decay) from breaking or to hold together parts of a cracked tooth
2. To restore an already broken tooth or a tooth that has been severely worn down
3. To cover and support a tooth with a large filling when there isn’t a lot of tooth left
4. To hold a dental bridge in place
5. To cover misshaped or severely discolored teeth
6. To cover a dental implant

What Types of Crown Materials Are Available?

Permanent crowns can be made from all metal, porcelain-fused-to-metal, all resin, or all ceramic.

*   Metals used in crowns include gold alloy, other alloys (for example, palladium) or a base-metal alloy (for example, nickel or chromium).

* Porcelain-fused-to-metal dental crowns can be color matched to your adjacent teeth (unlike the metallic crowns).

* All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures than porcelain-fused-to-metal crowns.

* All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type and may be more suitable for people with metal allergies.

* Temporary versus permanent. Temporary crowns can be made in your dentist’s office whereas permanent crowns are made in a dental laboratory. Temporary crowns are made of acrylic or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by the dental laboratory.

http://www.webmd.com/oral-health/dental-crowns

There are few causes

Abrasion - is due to mechanical tooth brushing.

Erosion - is due to diet acid and stomach regurgitation to increase acidic environment.

A - Pulpitis - Initial pulpitis, reversible pulpitis, acute irreversible pulpitis

B - Perio endo lesion

C - Dentine Sensitivity

Initial pulpitis or early reversible pulpitis

Pain hot / cold

Disappear on removal stimulus

Very short duration < 15 second

No spontaneous pain

Poorly localized

May include large intracoronal, extracoronal restoration, large caries involving pulp or pin closed to pulp.

I have A B C diagnosis answer. Because this question want me to answer through differential diagnosis.

Endodontic or root canal treatment

From http://rootdoctors.googlepages.com/

This all treament procedures

Determine root length

Gutta percha trial

Canal obturation

Above is normal anatomy picture of tooth.

I will give you points in Dental Caries

Begin:

The acids in plaque dissolve the enamel surface of the tooth and create holes in the tooth (cavities). Cavities are usually painless until they grow very large inside the internal structures of the tooth (the dentine and the pulp at the core) and can cause death of the nerve and blood vessels in the tooth, resulting in tooth abscess.

Dental caries[1] Early stages : acides dissolve the enamel in the crown of the tooth

[2] Moderate tooth decay : here the dentine is attacked by acids and bacteria invade the cavity.

[3] Advanced tooth decay : inflammation of the pulp.

[4] Necrosis (death) of the pulp tissue.

[5] Periapical abcess forms at the apex of the root

Acids begin to dissolve tooth enamel within 20 minutes after eating, the time when most bacterial activity occurs. Untreated tooth decay can result in death of the internal structures of the tooth with eventual loss of the tooth. Dietary sugars and starches (carbohydrates) increase the risk of tooth decay. The type of carbohydrate and the timing of ingestion are more important that the amount. Sticky foods are more harmful than non sticky foods because they remain on the surface of the teeth. Frequent snacking increases the time that acids are in contact with the surface of the tooth.

Treatment plan:

Oral hygiene is the primary prevention against dental caries. This consists of personal care (proper brushing at least twice a day and flossing at least daily) and professional care (regular dental examination and cleaning, at least once a year).

Chewy, sticky foods (such as dried fruit or toffee) are best if eaten as part of a meal rather than as a snack. If possible, brush the teeth or rinse the mouth with water after eating these foods. Minimise snacking, which creates a constant supply of acid in the mouth. Avoid constant sipping of sugary drinks or frequent sucking on sweets or mints unless sugar free.

The use of dental sealants is a good means of cavity prevention. Sealants are thin plastic-like coating applied to the chewing surfaces of the molars. This coating prevents the accumulation of plaque on these vulnerable surfaces. Sealants are usually applied on the teeth of children, shortly after the molars erupt. Older people may also benefit from the use of tooth sealants.

Fluoride is often recommended to protect against dental caries. It has been demonstrated that people who ingest fluoride in their drinking water or by fluoride supplements have fewer dental caries. Fluoride that is ingested when the teeth are developing is incorporated into the structure of the enamel and protects it against the action of acids.

Topical fluoride is also recommended to protect the surface of the teeth. This may include a fluoride toothpaste or mouthwash. Many dentists include application of topical (applied to a localised area of the skin) fluoride solutions as part of routine visits.

Source from:

http://greenfield.fortunecity.com/rattler/46/upali3.htm

In dentistry we study Aesthetic but in general we can looking around

Dry Ice Aesthetic Machine Demonstration Japanese TV Show Video

Design for an Aesthetic theatrical poster

In dentistry

Veneers restorations

Finally our Dentist must work in the clinic