28/May/2011

Topics

Introduction
What is nitrous oxide?
The goal of nitrous oxide inhalation..
Is nitrous oxide safe?
Is nitrous oxide safe for children?
What are the advantages of nitrous oxide?
Disadvantages of nitrous oxide?
Contraindications of nitrous oxide
What does it feel like?
Before taking nitrous oxide
Is nitrous oxide right for me?

Feeling Anxious About Dental Treatment?

Introducing…….

Nitrous Oxide Relaxation….

Transforming dental anxiety into soothing, peaceful relaxation with absolute safety.

Breathing nitrous oxide will put a smile on your face from the moment you slip into the dentist’s chair. This safe and highly effective method of patient relaxation has helped millions of people overcome their anxieties about dental treatment.

As you try nitrous oxide, your feelings of anxiety will melt away quickly and be replaced by a warm, gentle feeling. Patient describe the experince as peacefully floating in pleasant dreamlike state. The apprehensive child or adult, nitrous oxide can be the key to an enjoyable, comfortable and anxiety-free dental experience.

What is nitrous oxide?

Commonly known as “laughing gas”, nitrous oxide is a non-allergenic, non-irritating gas that affects the central nervous system. It is one of the safest forms of sedation available and is easily and completely reversed by breathing normally for 5 to 10 minutes following treatment.Nitrous oxide is used in combination with pure oxygen to relieve dentistry-related anxiety. When inhaled and absorbed into the body, nitrous oxide has a natural calming effect that lasts only as long as your dental procedure.

The goal of nitrous oxide inhalation..

The goal of use of nitrous oxide in dentistry is to eliminate dental anxiety, making the patient more comfortable while the sedation dentist is able to more effectively complete the planned dental care procedure while the patient is sedated. Consult with your dentist to find out if this pain free procedure right for you.

Is nitrous oxide safe?

COMPLETELY. Nitrous oxide is recognized as the safest sedative used in dentistry today. It is mild, non-toxic and removes itself naturally from your body after use. Its benefits are even recommended for patients with certain medical conditions, including high blood pressure, angina and a history of heart attacks. And, unlike general anaesthesia, patients on nitrous oxide remain fully conscious and responsive at all times.

Is nitrous oxide safe for children?

ABSOLUTELY. While our practice goes to great lengths to make every child feel at ease, some children required a degree of sedation to achieve successful treatment. Nitrous oxide is the safest, most effective form of sedation to relieve your child’s fears and ensure a positive experience.

Patient ready for nitrous oxide adminstration

What are the advantages of nitrous oxide?

It’s fast acting – Within minutes of administration, your stress will be transformed into a sensation of smoothing relaxation and pain-killing properties develop after 2 or 3 minutes..
Your depth of sedation can be adjusted easily – The depth of nitrous oxide sedation can be adjusted to quickly achieve your optimal level of relaxation. Other sedation techniques don’t allow for this. For example, with IV sedation, it’s easy to deepen the level of sedation, but difficult to lessen it.
Recovery time is short – In just 3 to 5 minutes after the flow of nitrous oxide is stopped (100% Oxygen flush), the effects completely disappear from your system. In fact, nitrous oxide is the only form of sedation that has no lasting after-effects that impair your ability to drive. You will simply feel refreshed and ready to go about your daily activities.
Certain procedures can be done without local anaesthesia – those that usually involved the gums such as deep cleaning. Nitrous oxide acts as a painkiller on soft tissues such as gums. However, its pain-relieving effects vary a lot from person to person and can’t be relied upon.
Very safe – Inhalation sedation has very few side effects and the drugs used have no ill effects on the heart, lungs, liver, kidneys, or brain.
Reduce gagging – Inhalation sedation can be very effective in eliminating or at least minimizing severe gagging.

Safety procedure — Monitoring the oxygen level and the hearth rate throughout the procedure will make gas sedation a safe procedure

Disadvantages of nitrous oxide?

Not comfortable with laughing gas – Some patients might afraid they might ‘lose control’ and some actually feel nauseous when inhaling nitrous oxide which are quite rare and usually due to over-sedation.
Inadequate of sedation – Some people will not achieve adequate sedation with permissible levels of oxygen.
Not comfortable with nasal mask – If you can’t breathe through your nose (either because you’re a pure mouth breather, or because your nose is blocked), or you feel too claustrophobic when something is put over your nose, it can’t be used.

Contraindications of nitrous oxide

Significant respiratory compromise
Upper respiratory tract infection
Conditions related to vitamin B12 deficiency
Nitrous oxide is relatively contraindicated in pregnancy

What does it feel like?

The most common sensations that patients experience are:

tingling of hands and feet
a general feeling of warmth
numbness of your legs, tongue and oral tissues
a ringing sensation or droning sound
feelings of euphoria
feelings of heaviness or lightness

If you feel nauseous while breathing nitrous oxide, please inform the dentist immediately so that the level can be adjusted.
Not everyone enjoys the feeling of nitrous oxide. If you feel uncomfortable at any time while breathing nitrous oxide, you can discontinue it at once by breathing deeply through your mouth. Be sure to let the dentist know so that the gas can be turned off.

Before taking nitrous oxide:

1. Do not eat or drink anything for 2 hours prior to your appointment. Otherwise you may feel nauseous or vomit during treatment.
2. Inform us of any changes to your medical history or any medications you are presently taking.
3. Use the restroom before your dental procedure.

Is nitrous oxide right for me?

Please discuss the possibility of nitrous oxide conscious sedation with us. It may be just the solution you or your child have been waiting for. If you have any questions regarding the use of nitrous oxide, feel free to discuss it with our dentist.

Porcelain Bridge

Nowadays, more and more people want to replace their missing teeth with the material that is as near as possible to their natural teeth. Porcelain fused to metal bridge is one of the conventional choice. However, because of the presence of metal in this type of material, the bridge somehow look dull, opaque and non-translucent. On top of that, it has a ‘dark’ margin due to the thinning of porcelain at that area especially dark gum line that is very obvious when patient smile. Porcelain bridge is invented to over come all the problems above. Because of its metal-free property, porcelain bridge can look like ‘real’ teeth and strong enough to withstand the biting force. The preparation on the teeth prior to porcelain bridge placement is same with the conventional bridge. Currently, for missing single tooth, we provide glass type of porcelain (eg. IPS e.max®) while for multiple missing teeth, zirconia bridge (eg. Procera®) will be used.

Cases of porcelain bridge

Case one: Missing front tooth

This young lady had a missing upper front tooth. She wanted replacement which looked as natural as possible. A porcelain bridge was suggested.

Unfortunately, the space for the front left central incisor was inadequate for a front tooth!!

Impression of her upper jaw and a study model was fabricated for assessment.

Diagnostic wax-up of the her bridge was made on the study model. Then, the patient’s teeth were prepared for bridge construction.

The porcelain bridge was constructed by laboratory technician. Back view of the bridge (below).

Full porcelain bridge IPS e.max®.

The porcelain bridge was cemented with transparent resin cement.

She was very pleased with the final outcome. Now she can smile!

Case 2: Badly decay front teeth

This young man presented with a badly decay front teeth with both lateral incisor placed behind. He wanted to make over all his front teeth.

In the assessment, we found numerous problems: decay front teeth, lateral front teeth placed backward and the canines looked unnatural. We started with root canal treatment on his front teeth. Due to backward position of the lateral incisors, we have the teeth extracted and after healing, he was ready for bridge construction. We proposed to him to have 2 porcelain bridge (each consist of 3 unit tooth) from his canine to the other side of his canine. (Want to know more about root canal treatment click here).

An study model was duplicated from his mouth and diagnostic wax-up was done to reassemble the final outcome of his bridges.

The teeth was prepared for bridges construction under local anaesthesia.

A provisional bridge was fabricated for him to wear while waiting for the final bridge

Finally, the porcelain bridges were cemented with transparent resin cement

The back view of the bridges with healing socket of the extracted lateral incisors.

Now, he can smile confidently!!

Topics

Problems with missing teeth
What is a dental bridge?
Anatomy of a dental bridge
Composition of a bridge
Types of dental bridge
How bridge is fitted
Cases done in our clinic
Maintenance of dental bridge
How Long do Bridges Last?

Problems with missing teeth

Most people want a gap in their mouth filled for cosmetic reasons, and understandably so: beautiful smile is a very important part of the impression you make to the outside world. However, there is a more important reason to close gaps in your mouth where teeth are missing; it is actually harmful to have a missing tooth, because teeth tend to drift out of place when there is a gap and move forward into the space that has been created. This leads to all kinds of serious problems, including bone loss, and, if left untreated, you can loose more teeth. Therefore, replacing a tooth is important!! Usually it can be done by fabricating a denture, bridge or implant.

What is a dental bridge?

implant-bridge — Bridge stting on the implants

A bridge is a way of replacing one or more missing teeth in the mouth. It is also known as fixed partial denture, which used to replace a missing tooth by joining permanently to adjacent teeth or dental implants. Unlike traditional removable dentures, a dental bridge is permanent as it’s anchored to the teeth at one, or both, sides using metal bands held in place by resin or cement. If well cared for, a dental bridge should last for 10 to 15 years.

Anatomy of a dental bridge

A bridge consist of a ‘false teeth/tooth which is called pontic connected by connectors to retainers. Bothe retainers sit on the abutment teeth: Retainers. Part of the bridge will have metal castings, called retainers. They are made to fit onto what the dentist has cut away on the abutment teeth. Retainers also secure and support the bridge’s artificial tooth or teeth. Pontics. A pontic is an artificial tooth that is suspended from the retainer casting. A pontic occupies the space formerly filled by the crown of a natural tooth. Connectors. A pontic is attached to a retainer by a connector. Connectors can be rigid or nonrigid. Nonrigid connectors take the form of male- and female-locking arrangements. Rigid connectors are classified as either cast or soldered. Abutments. The teeth that support and hold the retainer are called abutments. It is almost mandatory that an bridge be supported by an abutment at both ends. This requirement is waived in special situations. When a pontic is suspended from only one retainer, it is cantilevered.

Composition of a dental bridge

The materials used for the bridges include gold, porcelain fused to metal, or in the correct situation porcelain alone (full porcelain). The amount and type of reduction done to the abutment teeth varies slightly with the different materials used. The recipient of such a bridge must be careful to clean well under this prosthesis.

Types of dental bridge

There are three types of dental bridge: fixed, resin bonded, and cantilever. The type of bridge used will depend on the quality of the teeth on either side of the gap, as well as the position of the gap. 1.) Fixed Bridges With a fixed bridge, the false tooth, or pontic, is anchored to new crowns attached to the teeth either side of the gap. These crowns are usually made from porcelain with the new tooth made from either ceramic or porcelain. This forms a very strong bridge that can be used anywhere in the mouth. 2) Resin Bonded Bridges Sometimes called Maryland Bonded, these dental bridges do not involve crowning the adjacent teeth, so are useful where these show little or no previous damage. The new tooth is generally made from plastic and is attached via metal bands bonded to the adjacent teeth using resin. This type of bridge is particularly suitable for front teeth where stress is minimal, and the bond can be made out of view behind the teeth. 3) Cantilever Bridges These dental bridges are used where there is a healthy tooth only on one side of the gap. The bridge is anchored to one or more teeth on just one side. As a result, this type of bridge is generally only suitable for low stress bridges such as front teeth.

How your bridge is fitted

Getting a bridge usually requires two or more visits. While the teeth are numb, the two anchoring teeth are prepared by removing a portion of enamel to allow for a crown. Next, a highly accurate impression (mold) is made which will be sent to a dental laboratory where the bridge will be fabricated. In addition, a temporary bridge will be made and worn for several weeks until your next appointment. At the second visit, you permanent bridge will be carefully checked, adjusted, and cemented to achieve a proper fit. Occasionally your dentist may only temporarily cement the bridge, allowing your teeth and tissue time to get used to the new bridge. The new bridge will be permanently cemented at a later time.

Cases done in our clinic:

Case One: Multiple missing teeth This patient was a young female, wearing denture for more many years. She came to us, wanted something fix or permanent which looked more natural than her denture. She presented with multiple missing (below). After assessing her, we suggested a 9 unit bridge extending from upper left canine to her upper right molar with non-rigid connector between her upper right canine and first premolar. We also suggested her to have a implant-supported bridge for her upper left quadrant. Shade or colour selection was chosen and the remaining teeth were prepared for bridge construction under local anaesthesia. Impression of her teeth were taken and a dental model was fabricated. The laboratory technician construction the bridge on the model. The non-rigid connector just behind the right canine used to connect the rest of the bridge a the posterior right (above) The connector at the back of the upper right canine was covered properly with porcelain. The anterior part of the bridge was cemented onto patient’s mouth (above and below – the back view) Finally, the back portion of the bridge is cemented to the back molar Final result!! Case Two: Multiple missing teeth This gentleman complained that his old denture was getting shorten and he wanted something permanent His denture looked really old with discolouration over the ‘pink’ part of the denture On the palatal view showed multiple missing teeth involving the upper front and right side. A 9 unit bridge was constructed and cemented onto patient’s mouth. Due to bone resorption at the front part, ‘pink’ porcelain was added to supported his upper lip giving him a youthful look. Palatal view: the bridge extended from left canine to right molar Final result!!

Maintenance of dental bridge

Dental hygiene becomes a little more complicated if you have a bridge, making normal flossing impossible in that area, nevertheless you do have to take care that the teeth adjoining the artificial tooth are thoroughly cleaned. Even the best fitting bridge will still have gaps around and beneath it, and these can quickly accumulate damaging debris if you do not follow a strict hygiene regime.Your dentist can show you how to do this, using special floss (eg. superfloss) or flossing needles. These floss go ‘under’ the pontic area and area near to the abutment to remove the food usually stagnant there.

How Long do Bridges Last?

While crowns and bridges can last a lifetime, they do sometimes come loose or fall out. The most important step you can take to ensure the longevity of your crown or bridge is to practice good oral hygiene. A bridge can lose its support if the teeth or bone holding it in place are damaged by dental disease. Keep your gums and teeth healthy by brushing with fluoride toothpaste twice a day and flossing daily. Also see your dentist and hygienist regularly for checkups and professional cleanings. To prevent damage to your new crown or bridge, avoid chewing hard foods, ice or other hard objects.

More info on General Dental Treatment

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Dr. Ng HW

21/Feb/2011

Complications of dental extraction

Infection: Although rare, it does occur. The dentist may opt to prescribe antibiotics pre- and/or post-operatively if they determine the patient to be at risk.

Prolonged bleeding: The dentist has a variety of means at their disposal to address bleeding; however, it is important to note that small amounts of blood mixed in the saliva after extractions are normal, even up to 72 hours after extraction. Usually, however, bleeding will almost completely stop within eight hours of the surgery, with only minuscule amounts of blood mixed with saliva coming from the wound. A gauze compress will significantly reduce bleeding over a period of a few hours.

Swelling: Often dictated by the amount of surgery performed to extract a tooth (e.g. surgical insult to the tissues both hard and soft surrounding a tooth). Generally, when a surgical flap must be elevated (i.e. and the periosteum covering the bone is thus injured), minor to moderate swelling will occur. A poorly-cut soft tissue flap, for instance, where the periosteum is torn off rather than cleanly elevated off the underlying bone, will often increase such swelling. Similarly, when bone must be removed using a drill, more swelling is likely to occur.

Sinus exposure and oral-antral communication: This can occur when extracting upper molars (and in some patients, upper premolars). The maxillary sinus sits right above the roots of maxillary molars and premolars. There is a bony floor of the sinus dividing the tooth socket from the sinus itself. This bone can range from thick to thin from tooth to tooth from patient to patient. In some cases it is absent and the root is in fact in the sinus. At other times, this bone may be removed with the tooth, or may be perforated during surgical extractions. The doctor typically mentions this risk to patients, based on evaluation of radiographs showing the relationship of the tooth to the sinus. It is important to note that the sinus cavity is lined with a membrane called the Sniderian membrane, which may or may not be perforated. If this membrane is exposed after an extraction, but remains intact, a “sinus exposed” has occurred. If the membrane is perforated, however, it is a “sinus communication”. These two conditions are treated differently. In the event of a sinus communication, the dentist may decide to let it heal on its own or may need to surgically obtain primary closure—depending on the size of the exposure as well as the likelihood of the patient to heal. In both cases, a resorbable material called “gelfoam” is typically placed in the extraction site to promote clotting and serve as a framework for granulation tissue to accumulate. Patients are typically provided with prescriptions for antibiotics that cover sinus bacterial flora, decongestants, as well as careful instructions to follow during the healing period.

Nerve injury: This is primarily an issue with extraction of third molars, but can occur with the extraction of any tooth should the nerve be close to the surgical site. Two nerves are typically of concern, and are found in duplicate (one left and one right): 1. the inferior alveolar nerve, which enters the mandible at the mandibular foramen and exits the mandible at the sides of the chin from the mental foramen. This nerve supplies sensation to the lower teeth on the right or left half of the dental arch, as well as sense of touch to the right or left half of the chin and lower lip. 2. The lingual nerve (one right and one left), which branches off the mandibular branches of the trigeminal nerve and courses just inside the jaw bone, entering the tongue and supplying sense of touch and taste to the right and left half of the anterior 2/3 of the tongue as well as the lingual gingiva (i.e. the gums on the inside surface of the dental arch). Such injuries can occur while lifting teeth (typically the inferior alveolar), but are most commonly caused by inadvertent damage with a surgical drill. Such injuries are rare and are usually temporary, but depending on the type of injury (i.e. Seddon classification: neuropraxia, axonotmesis, & neurotmesis), can be prolonged or even permanent.

Displacement of tooth or part of tooth into the maxillary sinus (upper teeth only). In such cases, almost always the tooth or tooth fragment must be retrieved. In some cases, the sinus cavity can be irrigated with saline (antral lavage) and the tooth fragment may be brought back to the site of the opening through which it entered the sinus, and may be retrievable. At other times, a window must be made into the sinus in the Canine fossa–a procedure referred to as “Caldwell luc”.

Dry socket (Alveolar osteitis) is a painful phenomenon that most commonly occurs a few days following the removal of mandibular (lower) wisdom teeth. It is commonly believed that it occurs because the blood clot within the healing tooth extraction site is disrupted. More likely,alveolar osteitis is a phenomenon of painful inflammation within the empty tooth socket because of the relatively poor blood supply to this area of the mandible (which explains why dry socket is usually not experienced in other parts of the jaws). Inflamed alveolar bone, unprotected and exposed to the oral environment after tooth extraction, can become packed with food and debris. A dry socket typically causes a sharp and sudden increase in pain commencing 2–5 days following the extraction of a mandibular molar, most commonly the third molar. This is often extremely unpleasant for the patient; the only symptom of dry socket is pain, which often radiates up and down the head and neck. A dry socket is not an infection, and is not directly associated with swelling because it occurs entirely within bone — it is a phenomenon of inflammation within the bony lining of an empty tooth socket. Because dry socket is not an infection, the use of antibiotics has no effect on its rate of occurrence. The risk factor for alveolar osteitis can dramatically increase with smoking after an extraction.

Bone fragments Particularly when extraction of molars is involved, it is not uncommon for the bones which formerly supported the tooth to shift and in some cases to erupt through the gums, presenting protruding sharp edges which can irritate the tongue and cause discomfort. This is distinguished from a similar phenomena where broken fragments of bone or tooth left over from the extraction can also protrude through the gums. In the latter case, the fragments will usually work their way out on their own. In the former case, the protrusions can either be snipped off by the dentist, or eventually the exposed bone will erode away on its own.

Read more….

Dr. Ng HW

20/Feb/2011

What is bone graft in dentistry?

Bone graft is a material that used to replace missing bone or bone defect in the face and mouth region, particularly in jaw area for support of implant during implant placement. Bone graft can also be use support the cheek or the chin area for aesthetic reasons.
Usage of bone graft in dentistry:

Orthognathic (Corrective jaw surgery) Surgery
Alveolar Bone Grafting (ABG) procedure in cleft patient
Periodontal surgery (eg. Guided Bone Regeneration)
In implant dentistry, bone grafts are widely used in:
- Sinus augmentation
- To preserve the socket after dental extraction of implant placement later
- To repair defect after dental extraction
- To cover exposed implant fixture during implant placement

Bone augmentation is a term that describes a variety of procedures used to “build” bone so that dental implants can be placed.

Bone graft was use during open sinus augmentation

When do we use bone graft in implant surgery?

Bone graft is used when there is not enough of bone at the site where implant is intended to be placed. Usually, when the width or the height of the jaw bone is not enough to support the placement of implant.
Bone graft can be obtain from outside or from patient’s own bone (autologous bone). Autologous bone is the best bone to substitute missing bone due to its high survival rate and its capability of attract new bone formation.

Bone-graft-procedure — Xenograft material was used to graft bone defect after implant placement

Bone graft sources

Autograft (Autogenous Bone)

Autologous bone grafting involve taking bone graft from patient’s bone of the same individual who is receiving the graft. Bone can be harvested from intra-oral (in mouth) or extra-oral (outside the mouth); example iliac crest, rib, cavarium.

In oral and maxillofacial surgery, bones are harvested extra-oral under general anaesthesia to repair alveolus in cleft patient, reconstruct mandible or maxilla after tumor resection, condyle reconstruction etc.

In implant dentistry, the usual site in the mouth that used to get bone graft (Donor site) usually depends on surgeon preference, the quality and quantity required:

External oblique ridge (bone behind the lower last molar)
Chin area
Tuberosity (bone behind the upper last molar)

Advantages of autograft:

Less rejection because graft originated from the patient’s own body
The graft doesn’t carry any disease
Using autograft bone as grafting material produce the highest successful outcome and predictability because the graft is a vital (living) bone which has the property of osteoinductive and osteogenic, as well as osteoconductive to regenerate new bone.

Disadvantages:

Additional surgical site is required (2 site surgery)
Post-operative pain and complications

Allografts

Allograft bone, like autogenous bone, is derived from humans; the difference is that allograft is harvested from an individual other than the one receiving the graft. Allograft bone can be taken from cadavers that have donated their bone so that it can be used for living people who are in need of it.

puros-from-zimmer — Puros from Zimmer is allograft bone particles

There are three types of bone allograft available:

Fresh or fresh-frozen bone
Freeze-dried bone allograft (FDBA)
Demineralized freeze-dried bone allograft (DFDBA)

Allograft bone used in dentistry uses bone from cadaver that undergo process of removal of unwanted material such as fats, cells, antigens, and inactivates pathogens, while preserving the valuable minerals and collagen matrix. This material is than freeze-dried before package.
Advantages of allograft:

Less antigenic rejection because allogaft bone originated from the same species
No need additional surgical site is required (2 site surgery)
The success of grafting using allograft will be lesser than autograft as the material used is basically a dead tissues
However, this material still carry property of osteoinductive and osteoconductive to regenerate new bone

Disadvantages:

Allograft bone might carry certain unknown diseases that resist the cleaning process during preparation of the graft
The graft usually resorb faster than xenograft material
Additional cost to the surgery

Xenografts

Xenograft bone substitute has its origin from a species other than human, such as bovine bone (or recently porcine bone) which can be freeze dried or demineralized and deproteinized. This material still has the property of osteoinductive and osteoconductive to regenerate new bone.

Bio-oss — Bio-Oss from Geislich contains xenograft material

Advantages of xenograft:

No need additional surgical site is required (2 site surgery)
This material still carry bone regeneration property of osteoinductive and osteoconductive.
However, success of grafting using xenograft will be lesser than autograft as the material used is basically a dead tissues
Xenograft material last longer in the mouth therefore, it with maintain the bone thickness for years

Disadvantages:

Just like allograft, xenograft material might carry certain unknown diseases that resist the cleaning process during preparation of the graft
Additional cost to the surgery

Alloplastic grafts

Alloplastic grafts may be made from hydroxylapatite, a naturally occurring mineral that is also the main mineral component of bone. They may be made from bioactive glass. Hydroxylapatite is a Synthetic Bone Graft, which is the most used now among other synthetic due to its osteoconduction, hardness and acceptability by bone.

boneceramic — BoneCeramic isone of the example of alloplastic graft

Some synthetic bone graft are made of calcium carbonate, which start to decrease in usage because it is completely resorbable in short time which make the bone easy to break again.
Tricalcium phosphate which now used in combination with hydroxylapatite thus give both effect osteoconduction and resorbability.
Polymers such as some microporous grades of PMMA and various other acrylates (such as polyhydroxylethylmethacrylate aka PHEMA), coated with calcium hydroxide for adhesion, are also used as alloplastic grafts for their inhibition of infection and their mechanical resilience and biocompatibility. Calcifying marine algae such as Corallina officinalis have a fluorohydroxyapatitic composition whose structure is similar to human bone and offers gradual resorption, thus it is treated and standardized as “FHA (Fluoro-hydroxy-apatitic) biomaterial” alloplastic bone grafts.

Biological mechanism

Properties of various types of bone graft sources.
	Osteoconductive	Osteoinductive	Osteogenic
Alloplast	+	–	–
Xenograft	+	–	–
Allograft	+	+/–	–
Autograft	+	+	+

Bone grafting is possible because bone tissue, unlike most other tissues, has the ability to regenerate completely if provided the space into which to grow. As native bone grows, it will generally replace the graft material completely, resulting in a fully integrated region of new bone. The biologic mechanisms that provide a rationale for bone grafting are osteoconduction, osteoinduction and osteogenesis.^[1]

Osteoconduction

Osteoconduction occurs when the bone graft material serves as a scaffold for new bone growth that is perpetuated by the native bone. Osteoblasts from the margin of the defect that is being grafted utilize the bone graft material as a framework upon which to spread and generate new bone. In the very least, a bone graft material should be osteoconductive.

Osteoinduction

Osteoinduction involves the stimulation of osteoprogenitor cells to differentiate into osteoblasts that then begin new bone formation. The most widely studied type of osteoinductive cell mediators are bone morphogenetic proteins (BMPs). A bone graft material that is osteoconductive and osteoinductive will not only serve as a scaffold for currently existing osteoblasts but will also trigger the formation of new osteoblasts, theoretically promoting faster integration of the graft.

Osteopromotion

Osteopromotion involves the enhancement of osteoinduction without the possession of osteoinductive properties. For example, enamel matrix derivative has been shown to enhance the osteoinductive effect of demineralized freeze dried bone allograft (DFDBA), but will not stimulate de novo bone growth alone.

Osteogenesis

Osteogenesis occurs when vital osteoblasts originating from the bone graft material contribute to new bone growth along with bone growth generated via the other two mechanisms.

More Info

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Dr. Ng HW

20/Feb/2011

An articulator is a mechanical device used in dentistry which represents the anatomy of temporomandibular joint (the joint connecting lower jaw to the skull), upper jaw and lower jaw of patient to which upper teeth cast and lower teeth cast are fixed to the articulator in order to reproduce patient’s jaw movements. By nature, the purpose of these articulators can only be achieved when the position of the maxilla is duplicated with respect to the skull. The upper teeth cast should be mounted on a semi-adjustable articulator using a face bow. The closer the articulator matches the patient’s anatomy, the better the treatment outcome will be, hence shorter dental treatment time is required. It is a complex articulator which almost imitates the anatomy of the temporomandibular joint and follows the movement of your lower jaw. Therefore, it can be used in the fabrication of complex crowns, long span bridges and full mouth rehabilitation. This articulator is also used for jaw surgery (orthognathic) planning. Semi-adjustable articulator is adjustable in certain areas but not all. They have adjustable horizontal condylar paths, adjustable lateral condylar paths, adjustable incisal guide tables, and adjustable intercondylar distances. Nevertheless, this articulator is adequate for most of the cases. Uses of articulators

Educate to patient their jaw relation
Reproduce patient’s jaw movement like opening and closing of mouth
To diagnosis the state of patient’s occlusion
To help in treatment planning
To help in fabrication and modifying of dental restoration (dental crown and bridge)
To obtain good occlusion for dental restoration
For jaw surgery planning
Allows teeth arrangement for denture

Advantages of articulator

Dentist allows to adjust patient’s dental restoration on the articulator (outside patient’s mouth) without the disturbance of patient’s tongue, cheek, and saliva.
Reduce dental visits and treatment time because articulator helps to resemble patient’s jaw relation.
Adjustment and correction of dental restoration can be done in the absence of patient
With the help of articulator, your dentist allows to visualize the inner side of your teeth easily

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Dr. Ng HW

20/Feb/2011

In Malaysia, 2 persons are diagnosed with oral cancer every day where 75% seek treatment at the later stages and only half of them survives. According to the National Cancer Registry, Ministry of Health, mouth cancer is the third most common cancer among Malaysian Indian community. If cancer is detected earlier, the treatment outcome is more favorable and the chance of survival is definitely much higher. And of course, prevention is better than cure. Biopsy can be performed to detect the abnormalities of the swelling whether it is benign (good) or cancerous.

What is biopsy?

A biopsy is a procedure where a small part of tissue is removed so that it can be looked closely under microscope.

When is it indicated?

A sore or lesion on any area of your mouth which lasts for more than 2 weeks.
A white or red patch on your mouth.
An non-healing ulcer for more than 2 weeks.

What is the purpose of a biopsy?

a. For definitive diagnosis so that correct treatment can be initiated as soon as possible

b. To establish prognosis of a pre-cancerous or cancerous lesion

Types of biopsy

There are few types of biopsy but most commonly used are:

a. Incisional biopsy

A small portion of suspicious swelling will be removed and sent to the laboratory for diagnosis purpose.
Pathologists will determine the nature of the swelling and staging of swelling if it is found to be cancerous.
Often indicated when the swelling is large and has differing charecteristics, so it may need investigation on several areas.

b. Excisional biopsy

Whole swelling will be removed for both diagnosis and treatment purpose.
Often indicated when the swelling is small, usually less than 2cm.

How is it performed?

The procedure is painless as it is done under local anesthetic (numbing injection). Dentist will take small piece of the tissue and stitching is often required afterwards. The tissue specimen will then be labeled and stored into container with special solution inside. It will be sent to the laboratory for investigation. The procedure usually takes 15 minutes from start to finish.

So, if you have a persistent swelling inside your mouth, do seek a dentist for consultation. Don’t be panic, not all the swelling are cancerous but it is better to get it check as soon as possible.

Different Types of Gum Surgery

There are certain types of gum surgery that usually the dentist will perform depend on the condition of the patient’s gum:

Pocket reduction (Gingiva Flap Surgery) This procedure is indicated for patient with deep pocketing on his gum as the result of gum disease (periodontitist). In this procedure, dentist or periodontist (gum specialist) will reflect the gum to expose the root of deep cleaning and then reposition the gum slightly lower in order to reduce pocket. Thus, this allows the patient to clean his teeth more efficiently.

Regeneration (Guided bone regeneration GBR) When there is excessive bone lost to a single or few teeth in the mouth, the dentist/periodontist might try to ‘re-grow’ the bone back around the tooth. The procedure can be done only after the gum disease ceased. Dentist/periodontist folds back the gums and removes disease-causing bacteria, then inserts bone grafts, membranes, or tissue-stimulating proteins (or any combination of the three) to encourage your gum tissues to regenerate and fit snugly around the teeth again.

Crown lengthening This procedure is done to lengthen the crown of the tooth for restoration later (Example: porcelain crowns or fillings). In cases where the tooth breaks down badly, sometimes, up to the gum level; crown lengthening is performed before restoration. The gum around the tooth will be removed to expose the root. This can be done with laser or electrocautery under local anesthetic. Once the gum healed, the tooth finally will be restore with filling or porcelain crown.

Removing excessive gum (Gingivectomy) In certain conditions where overgrowth of gum covering the teeth (gingiva hyperplasia), gingivectomy can be performed to reduce it. Gingiva hyperplasia usually cause be irritation to the gum, or certain medication patient taking causing the gum grows excessively or can be unknown reason. Basically, gingivectomy improves the teeth aesthetically and reduce plaque accumulation around them.

Soft tissue graft (Gingivoplasty)This procedure is performed on the gum that is thin and receded due to over-brushing. Dentist will take a tissue from elsewhere in your mouth (usually on the palate) and attaches it to your gums to replace gum tissue that has receded or has been removed due to gum disease. This procedure is often used for cosmetic purposes as well as to treat gum disease because it covers areas where the root is becoming exposed and improves the appearance of the teeth.

Is Gum Surgery Painful?

Most people will have only mild to moderate pain after surgery that can be managed with pain relievers. If the is moderate swelling on the gum, cold pack can be used to reduce it. Usually the dentist will give instructions on managing the wound after surgery.

More info

Treatments of gum disease:

Scaling and polishing
Air Polishing – A way to eliminate staining due to smoking, coffee or tea
Root Planing
Gum Surgery
Cosmetic Gum Surgery
Gingivoplasty
Gingivectomy
Fear of Dental Treatment? How to overcome it..?

Dr. Ng HW

20/Feb/2011

Complex Extraction

Unfortunately, not all extractions can be done by simply grasping the tooth with forceps and rocking it out. What if there is nothing left above the gum line to grasp? Or what if the crown breaks off leaving the roots still in the bone? These things can and do happen, and any dentist that extracts teeth will have to deal with them routinely.

In these cases, it becomes necessary to surgically remove the tooth. This is frequently accomplished by prying the root out using a sharp instrument that can be forced between the root and the bone surrounding it. This technique is called “luxation“. In the case of multiple rooted teeth, the roots are first separated so they can be removed individually. Unfortunately, not all roots or root fragments may be removed in this fashion. This means that the dentist must make an incision into the gums around the tooth and raise a flap of tissue exposing the tooth and its surrounding bone.

Surgical-Extraction — Surgical Extraction – a. Gum flap is raised and surrounding bone is removed. b. The roots of the molar are split with a drill and removed. c. The flap is held back in place with sutures

Sometimes, after the flap is raised, there is enough tooth exposed to grab and remove it as in a simple extraction. Sometimes, the technique described above as luxation may successfully remove the tooth. If luxation fails, the dentist must take a handpiece (drill) and cut away some of the surrounding bone in order to gain a purchase on the tooth. After the tooth has been pried out of the artificially enlarged socket, the dentist then sutures (sews) the flap of tissue back in place so that healing can proceed normally.

Introduction

Cosmetic gum surgery – It is a type of surgery used to reshape healthy gum tissue around the teeth to make them look better. If a person has tooth recession where the gum is pushed away from the tooth, a gingivoplasty surgery can be done. Basically to ‘bring’ back the gum to cover the expose root surface of a tooth:

Before cosmetic gum surgery (gingivoplasty surgery) – receding gum especially on patient’s left side

After cosmetic gum surgery *(gingivoplasty surgery)*

To read more on the gingivoplasty procedure click here.

On the other hand, if there is excessive gum covering the teeth, then the procedure is to remove some part of the gum covering the teeth (gingivectomy surgery) to show more of the tooth thus reduce gummy smile and improve smile line.

To read more on the gingivectomy procedure click here.

After gum surgery, it is important that the periodontist or dental hygienist inform you how to clean the teeth and gum tissue with a toothbrush and an antimicrobial fluoride toothpaste, floss and antibacterial mouth rinse. Please consult your periodontal specialist or dentist for more information of how to care for your gum tissue and teeth after gum surgery.

Topics

Feeling Anxious About Dental Treatment?

Introducing…….

Nitrous Oxide Relaxation….

What is nitrous oxide?

The goal of nitrous oxide inhalation..

Is nitrous oxide safe?

Is nitrous oxide safe for children?

What are the advantages of nitrous oxide?

Disadvantages of nitrous oxide?

Contraindications of nitrous oxide

What does it feel like?

Before taking nitrous oxide:

Is nitrous oxide right for me?

Read More

Porcelain Bridge

Cases of porcelain bridge

Case 2: Badly decay front teeth

Read more

Topics

Problems with missing teeth

What is a dental bridge?

Anatomy of a dental bridge

Composition of a dental bridge

Types of dental bridge

How your bridge is fitted

Cases done in our clinic:

Maintenance of dental bridge

How Long do Bridges Last?

Read more

More info on General Dental Treatment

Complications of dental extraction

Read more….

What is bone graft in dentistry?

When do we use bone graft in implant surgery?

Bone graft sources

Autograft (Autogenous Bone)

Allografts

Xenografts

Alloplastic grafts

Biological mechanism

Osteoconduction

Osteoinduction

Osteopromotion

Osteogenesis

More Info

What is biopsy?

When is it indicated?

What is the purpose of a biopsy?

Types of biopsy

a. Incisional biopsy

b. Excisional biopsy

How is it performed?

Read More…

Different Types of Gum Surgery

Is Gum Surgery Painful?

More info

Treatments of gum disease:

Complex Extraction

Read more….

Introduction

Read More…