Porcelain

Dental porcelain (also known as dental ceramic) is a porcelain used by a dental technician to create biocompatible life like crowns,bridges, and veneers for the patient. Evidence suggests they are effective biocompatible, esthetic, insoluble and have hardness of 7 on the Mohs scale), although for three-unit molars porcelain fused to metal or in complete porcelain group only zirconia-based restorations are recommended.[1]

The dentist will usually specify a shade or combination shades for different parts of the restoration, corresponding to a set of bottles in the lab containing the porcelain powder. A common shade system used is the Vita guide (Vita Classical and Vita 3D Master). There are two types of porcelain restorations: porcelain fused to metal and complete porcelain. For porcelain fused to metal, the black colour of metal is first masked with an opaque layer to make it a shade of white and then consecutive layers are built up. The powder corresponding to the desired shade of dentine base is mixed with water, and then fired. Further layers are built up to mimic the natural translucency of the enamel of the tooth. The porcelain is fused to a semi-precious metal or precious metal such as gold, for extra strength. Many systems use an aluminium oxide or zirconium oxide or zirconia core instead of metal that makes complete porcelain restorations.

Recent developments in dental CAD - CAM technology have required specialized porcelains formed into sintered blocks. CAD/CAM restorations created with CEREC technology appear to last well.[2]

Dental porcelain is generally regarded as biologically inert. However, other toxicities may exist from depleted uranium and some of the other accessory materials, and the fillings may increase wear on opposing teeth.[3]

References

• The National Association of Dental Laboratories http://www.nadl.org/
• Napier, Bennett. Letter to the Food and Drug Administration. "Dear Interagency Working Group on Import Safety,"National Association of Dental Laboratories, September 10, 2007. http://www.nadl.org/pdfs/NADLLettertoFDA09102007.pdf

Footnotes

• Della Bona A, Kelly JR (September 2008). "The clinical success of all-ceramic restorations". J Am Dent Assoc139 Suppl: 8S–13S. PMID 18768903.
  http://jada.ada.org/cgi/pmidlookup?view=long&pmid=18768903.
• Fasbinder DJ (September 2006). "Clinical performance of chair side CAD/CAM restorations". J Am Dent Assoc137 Suppl: 22S–31S. PMID 16950934. http://jada.ada.org/cgi/pmidlookup?view=long&pmid=16950934.
• Mackert JR (September 1992). "Side-effects of dental ceramics". Adv. Dent. Res.6: 90–3. PMID 1337968. http://adr.iadrjournals.org/cgi/pmidlookup?view=long&pmid=1337968.

Porcelain Crowns

Also called Ceramic Crowns

• Crowns are usually constructed to restore teeth that have sustained a lot of damage.
• Porcelain or Ceramic Crowns are made according to the colour of the adjacent teeth and when done well are very aesthetically pleasing.
• They are made outside of the mouth (Dental Lab) and are cemented on (indirect) whereas Composite Crowns can be constructed directly in the mouth
• Porcelain Crowns may be all ceramic/porcelain or may have a metal substructure for extra strength
• Porcelain is relatively strong but can still undergo wear and fracture in normal use
• Porcelain surfaces are very hard and may actually abrade or wear the opposing tooth enamel and dentine
• For strength and aesthetics Porcelain Crowns usually require greater drilling than Full Gold Crowns or Composite Crowns
• Porcelain Crowns cost around $1,800





Porcelain Veneers

See also Veneers

1. Porcelain Veneers are thin Ceramic covers that are Bonded onto teeth to improve colour and shape and overall appearance
2. When done well both Porcelain Veneers and Composite Veneers are very Aesthetic but Porcelain does have one advantage. Bacteria have a harder time sticking to porcelain and are thus easier to keep clean. If you find it hard to clean your teeth and have decided on Veneers then Porcelain Veneers may be a better option
3. Some dentists claim that Porcelain Veneers are a stronger option. But after over twenty years of placing Veneers when done properly there is little or no difference. The difference is related to individual Functional and Parafunctional habits. In fact, if any Veneer does Fracture, and Porcelain veneers do (see Porcelain Fractures), then it is the Composite Veneer that is repairable not the Porcelain. Porcelain like glass, is a brittle material where as modern Nano Composites are tougher see Toughness
4. Porcelain Veneers usually require more drilling of teeth (such as in between the teeth and on the biting edges) than Composite Veneers. This is done in order to:
1. Give Porcelain more strength and retention and
2. So they don’t look too opaque, bulky and fake
5. Porcelain Veneers usually require two visits (may need a third if any adjustments are made) and cost around $1200 each
6. They can be difficult to get right. At Sydney Aesthetic Smiles we have removed unaesthetic Porcelain Veneers and replaced them with Composite Veneers

Pregnancy

There is no reason why a pregnancy should cause you to lose your teeth unless you ignore them totally.

“Morning sickness” may make oral hygiene more difficult.

More frequent snacking will also encourage greater bacterial growth.

During pregnancy the gums become more sensitive to bacterial irritation and may show an increased inflammation response. The type of bacteria around the teeth may also change to a type more associated with the cause of periodontitis. It is very important to maintain good oral hygiene and have regular dental checks during pregnancy.

Periodontitis can show a family tendency. So if a mother or father has periodontitis then there is an increased risk for their children to have periodontitis. Regular dental checks for periodontitis are even more important for those at higher risk for periodontitis.

Gingivitis due to Pregnancy

Pregnancy can worsen mild gingivitis, primarily because of hormonal changes. Some pregnant women may unknowingly contribute to the problem by neglecting oral hygiene because they feel nauseated in the morning (morning sickness). Also, during pregnancy, a minor irritation, often the build up of tartar, may cause a lump like overgrowth of gum tissue, called a pregnancy tumor. The bloated tissue bleeds easily if injured and may interfere with eating.

If pregnant women are neglecting oral hygiene because of morning sickness, dentists can suggest ways to keep the teeth and gums clean without exacerbating the nausea. Gentle brushing without toothpaste or even salt water rinses after brushing can help. A bothersome pregnancy tumor can be surgically removed. However, such tumors tend to recur until, and even after, the pregnancy ends.

When we are PREGNANT our life does change alongside of the changes in our body. We are more susceptible to GINGIVITIS (gum disease)This occurs because of our hormone levels rising. It is very important to brush and floss correctly 2-3 times a day as well as visiting a dentist.

If you do develop gum disease and the gum disease becomes severe it becomes periodontitis. This can affect your unborn baby development. Such as premature birth and low weight is also possible.

SIGNS OF GINGIVITIS

Swollen gums
Bleeding when tooth brushing
Gums changing colour from pink to a dark pink, red colour



Diet is a very important factor during our pregnancy as we are not only eating for ourselves but also for our growing baby. Follow the five food groups such as fruit & vegetables, grains, pasta,rice,lean meats, cheeses and yoghurt are some examples Ask for brochures on diet when visiting your Gyno/Ob or your Midwife

Cravings are common when we are pregnant. If we do crave sweet food try to substitute with a skim milk milkshake with real strawberries in it.

Diet is a very important factor during our pregnancy as we are not only eating for ourselves but also for our growing baby. Follow the five food groups such as fruit & vegetables, grains, pasta,rice,lean meats, cheeses and yoghurt are some examples Ask for brochures on diet when visiting your Gyno/Ob or your Midwife

Cravings are common when we are pregnant. If we do crave sweet food try to substitute with a skim milk milkshake with real strawberries in it.

PULP/NERVE

“The nerve”

What people call the nerve is actually a complex, sensitive and very delicate conglomerate of dentine cells, connective tissue cells, small arteries and veins, capillaries and nerve tissue.



Latin	pulpa dentis
MeSH	Dental+pulp

The dental pulp is the part in the centre of a tooth made up of living connective tissue and cells called odontoblasts.

Anatomy

Each person can have a total of up to 52 pulp organs, 32 in the permanent and 20 in the primary teeth. The total volumes of all the permanent teeth organs is 0.38cc and the mean volume of a single adult human pulp is 0.02cc. Maxillary central incisor has shovel shaped coronal pulp with three short horns on the coronal roof and triangular in cross section. Cuspid has the longest pulp with elliptical cross section.

Crowns of the teeth contain coronal pulp. The coronal pulp has six surfaces: the occlusal, the mesial, the distal, the buccal, the lingual and the floor. Because of continuous deposition of dentin, the pulp becomes smaller with age. This is not uniform throughout the coronal pulp but progresses faster on the floor than on the roof or side walls. Radicular pulp is that pulp extending from the cervical region of the crown to the root apex. They are not always straight but vary in shape, size and number. The radicular portion is continuous with the periapical tissues through the apical foramen or foramina.

Apical foramen is the opening of the radicular pulp into the periapical connective tissue. The average size is 0.3 to 0.4 mm in diameter. There can be two or more foramina separated by a portion of dentin and cementum or by cementum only. Most infections spread through the apical foramen from the pulp to periapical tissue. Accessory canals are pathways from the radicular pulp, extending laterally through the dentin to the periodontal tissue seen especially in the apical third of the root.

Structural features
Pulp tissue removed during endodontic therapy by a size 20 broach file. The central region of the coronal and radicular pulp contains large nerve trunks and blood vessels. This area is lined peripherally by a specialized odontogenic area which has three layers (from innermost to outermost)

• 1. Cell rich zone (of Rinaggio); innermost pulp layer which contains fibroblasts and undifferentiated mesenchymal cells
• 2. Cell free zone (zone of Weil) which is rich in both capillaries and nerve networks. The nerve plexus of Raschkow is located in here
• 3. Odontoblastic layer; outermost layer which contains odontoblasts and lies next to the predentin and mature dentin

Cells found in the dental pulp include fibroblasts (the principal cell), odontoblasts, defence cells like histiocytes,macrophage, granulocytes, mast cells and plasma cells.

Clinical significance

An inflammation of a pulp is known as pulpitis. Pulpitis can be extremely painful and in serious cases calls for root canal therapy[1].

Functions
The primary function of the dental pulp is to form dentin (by the odontoblasts) Other functions include

• Nutritive: the pulp keeps the organic components of the surrounding mineralized tissue supplied with moisture and nutrients;
• Sensory: extremes in temperature, pressure, or trauma to the dentin or pulp are perceived as pain;
• Protective: the formation of reparative or secondary dentin (by the odontoblasts).

Putrefaction

Putrefaction is the decomposition of animal proteins , especially by anaerobic microorganisms , described as putrefying bacteria . Decomposition is a more general process. Putrefaction usually results in amines such as putrescine and cadaverine , which have a putrid odor. Material that is subject to putrefaction is called putrescible

See Gum Disease

Brief description of putrefaction of a human body with respect to time of death:

2–3 days: Staining begins on the abdomen. The body begins to swell, owing to gas formation.

3–4 days: The staining spreads and veins become discoloured.

5–6 days: The abdomen swells with gas (produced by the bacteria that decompose the body), and the skin blisters.

2 weeks: The abdomen becomes very tight and swollen.

3 weeks: Tissues begin to soften. Organs and cavities are bursting. The nails fall off.

4 weeks: Soft tissues begin to liquefy, and the face becomes unrecognizable.

The exact rate of putrefaction is dependent upon many factors, such as weather, exposure and location. Thus, refrigeration at a morgue or funeral home can retard the process, allowing for burial in three days or so following death without embalming.

The Perfect Face



Florence Colgate was recently crowned the most beautiful woman in Britain.

The 18-year-old student beat 8000 other participants in a competition in the search of the “Perfect Face”. Contestants were judged without makeup and were barred entry if they received plastic surgery or chemical enhancement.

Some speculated her beauty secret was the air in her home town, or possibly a special ingredient in the chips from the seaside shop she was part-timing at. But it was really the blue-eyed blonde’s flawless mathematical facial proportions that added up to her success in winning the title as Britain’s most naturally gorgeous face.



Miss Florence Colgate, 18, is blessed with the perfect proportion and symmetry for beauty.

The ancient Greeks found major consistencies in the proportion between various sections of attractive faces. A set of model facial proportions – the Neoclassical Canon (or the “artistic ideal”) – was created as a guide for painters and sculptors. For example, a woman’s face is said to be most beautiful when the relative distance between eyes and mouth is just above a third of the measurement from hairline to chin. And Miss Colgate’s ratio – 32.8 per cent.

The Golden Ratio – ratios of 1 to 1.618 (or phi) between various features or body parts – is another set of “divine proportions” that’s been used in great works like Da Vinci’s Mona Lisa and Vitruvian Man. For a quick facial analysis, different divine proportions of the female face have been put together in the “Phi Mask” by Dr Stephen Marquardt; and it matches a heart-shaped face with well-balanced features as popularized by ageless superstar, Madonna.

For Florence Colgate, perfect symmetry, or how one half of the face mirrors the other, further ads up to her beauty score sheet. Facial symmetry is thought to be an important hidden cue for attractiveness with a more primal background: If you have a history of poor developmental stability (such as a major illness in early childhood or nutritional deficiency in the womb) which may affect your abilities to have a healthy vigorous brood, you tend to have more asymmetrical features.

CREATE YOUR OWN PERFECTION

Mind-boggling theories and numbers aside, the more practical question (and the real reason why you’re still reading) is: How can we utilise these principles to enhance our own beauty?

Armed with these tools to crack the secret codes of beauty, great artists have created masterpieces that have endured the test of time, and plastic surgeons have carved their careers (along with big fortunes) by perfecting faces with their scalpels. The good news is, advancement in medical aesthetic technology and techniques now allows us to get one step closer to divine beauty without undergoing the blade!



(Left) Based on the Golden Ratio, Dr Stephen Marquardt's 'Phi Mask' matches the perfect heart-shaped face with well-balanced features. (Right) Beautiful young faces are always curvaceous. Putting a 3-dimenshional "Ogee Curve" (where one curve is phi times the length of the other) in faces make older people look younger and younger faces more beautiful.

“Instead of creating ‘cookie-cutter’ beauties with the same ‘Anne Hathaway’ eyes and the same ‘Natalie Portman’ nose, we employ some of these mathematical principles in our treatments to bring out the best of each individual by working towards the ideal facial contour, harmonious proportions and balanced facial curves,” says Dr Tan Wang Theng, from The Sloane Clinic

“With that, mature faces will look more youthfully attractive, and young faces more naturally beautiful.”





CONTOUR & SCULPT: BOTOX JAW & ULTHERAPY

Botox in the masseters (jaw muscles) is the open celebrity secret behind many fabulous V-shaped jawlines – allowing you to slim down a heavy, squarish jaw miraculously without downtime. For the perfect heart-shaped face, Ultherapy in the lower face tucks and lifts fatty soft tissue and saggy jowls sans surgery for a lean, naturally defined and elegantly grown-up look.

ACCENTUATE & DEFINE: DERMAL FILLERS

Juvederm Voluma, the latest generation natural filler, allows for precise contouring of balanced and curvy killer cheeks,while restoring a dewy, bouncy firmness for an impressive 18 months. Due to its unique particle size, Voluma is also optimally suited for sculpting a more defined nose or a chin that’s in proportion to the entire face, and boosting sunken temples to build a perfect frame for the eyes and brows.




“Like the famous saying goes, ‘Pretty may be what you’re born with. But Beautiful, now that’s an equal opportunity adjective.’” says Dr Tan.





And that’s probably more true today then ever before, with the wide selection of clinically proven non-surgical and surgical advanced treatments which bring the classic mathematical rules of beauty from canvas to life.

- By Claudia Lin