Dental Burs

Diamond burs are generally used for reducing tooth structures to prepare cavities for restorations or place crowns or porcelain veneers. Diamonds may also be used to smooth, refine, and polish composite or porcelain material.

Tooth Whitening

Photograph showing before and and after teeth whitening procedure. 

Tooth whitening is done to correct the discoloration of a tooth. When we talk about discoloration of a tooth, we mean to say that  the color of a tooth has changed from its normal white color to  light yellow,  yellow,  light brown to dark brown  or from light grey to dark grey or  to complete black. The discolouration may be of one tooth or all the teeth may be discoloured. Discoloration of a tooth is caused by several factors. It may be due to deposition of external stains over the surfaces of a tooth or it may be because of the internal position of certain chemicals into the teeth structure at molecular level during the period when teeth were being formed in the mother’s womb.

Composites: Composition

Composites are tooth coloured restorative materials that are usually recommended for class III, IV and class I cavities with less or no occlusal stress and esthetics are important. Specially designed composites are used in almost 50% of class II restorations, although less durable in comparison to dental amalgam. Composites can be classified as microfilled, nanofilled, flowable, packable, all purpose and laboratory. Composites are used for provisional restorations and core build-ups and in fibre-reinforced posts.

Composites: Properties

You have read about the composition of dental composites in earlier class notes This article will speak about the properties. 

Properties of Composites

The important properties of the composites are as follows:

1. Polymerisation shrinkage - should be low
2. Water sorption - should be low
3. Coefficient of thermal expansion - should be same as tooth
4. Fracture resistance - should be high
5. Wear resistance - should be high
6. Radiopacity- should be high
7. Bond strength to enamel & dentin - should be high
8. Colour match to tooth structure - should be excellent
9. Manipulation - should be easy
10. Finishing and polishing - should be easy

Few of the above mentioned properties may be important for anterior than posteriors restorations and vice versa. The properties of 

microfilled and nanofilled composites are same while the microhybrid's differ from both of them.

Direct Esthetic Restorative Materials

There are four types of direct esthetic restorative materials currently in use. They are:

1. Composites
2. Compomers
3. Hybrid Ionomers
4. Glass Ionomers

Composites are dominating the materials used for direct esthetic restorations. Glass ionomers are primarily used for restorations of cervical eroded areas. Hybrid ionomers provide better esthetics than glass ionomers. Compomers provide improved handling and fluoride release when compared with composites.

Journey of a Dentist for ADC Exam

Introduction

This story of a dentist tells about the journey of a dentist for ADC exam and the mental, physical and economic sufferings full family went through after his failure.

Ganesh was a general dental practitioner with a nice practice in a class two city. Isha was a tutor in a Dental college in the same city. The couple had been living a happily married life with their 5 years old son and their parents in a joint family.

Journey of Dentist to Australia: Part 2

Saudi Arabia Riyadh landscape at Morning – Riyadh Tower Kingdom Centre, Kingdom Tower, Riyadh Skyline – Burj Al-Mamlaka, AlMamlakah – Riyadh at Daylight – Tower View-Getty Images

Click to read part 1 of the story at the link given below

Journey of Dentist to Australia: Part 1

....... Continues

With the passage of time,  Ganesh became aware of the situation of his family. He started to understand the pain of his wife and the thought process of his father. He, who always cared for him, was worried about his future; the future ahead of his family life as well as financials, as it has to have a long lasting effect on his Son too.

Both Ganesh and his wife dropped the idea of ADC as it was clear, no matter how hard they try it, it was not meant for them. Moreover, they were out of funds, rather, better word was, in negative funds. So, to regain their lost finances, they modified their plan. 

The plan was to try for a gulf job and regain the lost finance. They consulted with their friend who had the experience of the gulf job. Ganesh and his wife got a decent job in Saudi Arabia. It was a job in a remote area of the Kingdom, but since they had their own circumstance, they adjusted themselves in a few months.

In this world there is no end of issues, no matter where a person lives. This soon started being applied to them too. A recently came new dentist in their workplace had Arab origin and the staff started giving him preferential treatment. The distribution of work started skewing, putting Ganesh in a difficult situation. His wife was cool as being a female, she was spared or the person involved had no guts to disturb her and be caught in a situation that might have backfired.

Ganesh contacted his friend for solace. He understood his situation and the options available. He decided, as long as I am getting my salary, I have to stay here and refill my coffer. There was no second choice.

His wife and he stayed for five years in Saudi Arabia and then started thinking of  coming back to India. They have earned sufficient, filled their coffer and most importantly regained the lost self esteem and self worth. Their family life has again come back on the smooth track.

Before coming back to India, Ganesh refurbished his old clinic when he had visited India last time. It was ready to start the work. Ganesh started working  in his own clinical practice the next day of arrival to India. His wife got her old tutoring job back in the same college she was teaching in. Within a year, they decided to open a second clinic. Soon it was booming by the hard working ethics of his wife, who decided to go take the clinical practice as full time work.

The couple decided to buy a house near their old home and were happy ever after. Ganesh remained obliged to his friends who supported him during his bad time. 

Polysulfide Impression Materials

Permlastic is a polysulfide, condensation-cured, elastomeric impression material in three viscosities

Polysulfide impression materials are flexible but do not have the major changes in dimensions during storage like agar and alginate. Furthermore, the polysulfide impression is much stronger and more resistant to tearing than agar or alginate. It can be electroformed and therefore metal dies or models, in addition to gypsum models, can be prepared. 

Design of a Custom Tray for Final Impression for Complete Denture

The custom trays also known as special trays are fabricated so that the final impression of the patient’s edentulous mouth can be taken accurately with proper border extension. The selective pressure technique helps in making the impression in such a way that when the newly fabricated dentures are worn by a patient, they exert pressure only on those areas of the mouth that can withstand the masticatory load. The selective pressure technique of impression making spares the non-pressure bearing area of the edentulous jaw and thus eliminate the possibility of trauma resulting in pain and ulceration in the mucosa. The special tray for selective pressure technique is made on the primary cast that has been prepared by pouring the impression made in alginate or impression compound. The impression taken in impression compound records the mucosa in a compressed state whereas the impression taken with alginate records the mucosa in a non-compressed state. From these two opposite states of mucosa record, a dentist proceeds to prepare a special tray that is used to make an impression with selective pressure. We will learn here as to how to make a special tray on a cast that has been made from impression compound. 

Non-carious loss of tooth structure

 

Types, clinical features, Causes prevention & treatment

Non-carious loss of tooth structure is a problem that is often found in senior citizens and is a cause of many complaints. It is not a new entity but has acquired more attention in recent time.

Types of tooth wear

1. Abrasion
2. Attrition
3. Erosion
4. Demastication
5. Abfraction

 

Abrasion

It is loss of tooth substance by the friction with a foreign substance. These are smooth and usually C shaped, more wide than deeper.

Clinical Features

These are usually facio-cervical concavities that are more broad than deep and can be associated with an abrasive diet. They are usually found on prominent teeth in the arch (i.e., canines, premolars, and mesio-buccal aspects of first molars). They may affect several teeth in a row with a “band” of abrasive damage. Sometime they may cause hypersensitivity.

Figure 1. Abrasion: note the concave smooth cavities in the cervical regions of upper and lower teeth.

Causes of Abrasion

It is mostly located in the cervical area of the teeth. The reason may be one or a  combination of the following  factors:

• Excessive tooth brushing for longer period
• Use of hard tooth brush
• Use of tooth paste containing highly abrasive material
• Use of locally prepared tooth cleaning powder or paste like Gul, Gulak or Lal Manjan
• Repeatedly putting foreign objects in the mouth like pipe smoking, pen, bobby pins and any other occupational material.

Prevention of Abrasion

Use of common sense is the best way of preventing the abrasion. If the cause is a hard tooth brush or brushing the teeth for a longer duration or use of an excessively abrasive tooth paste. Then correcting the hardness of the tooth brush, adjusting the time, and changing the tooth paste will be sufficient. If the cause is abrasive food or any occupational factor, this may be difficult to treat but not impossible. 

Treatment of Abrasive Lesions

 The treatment of the cavities created by abrasion is the restoration of teeth by Glass Ionomer or tooth coloured composite filling material. These types of fillings or restoration fall under the category of 'Cosmetic' or 'Aesthetic' 'Restorations'. 

Sometimes, the depth of the abrasive lesion is so deep that it affects the pulp in an adverse way. In this stage, it is better to get the 'Root Canal Treatment' before going for aesthetic restoration. But, if the lesion had been there since long, the involved tooth may need extraction. 

Attrition

It is the loss of tooth material due to tooth to tooth contact. It usually occurs on occlusal and incisal  surfaces.                                

Clinical Features

They show matching occlusal wear between arches and shiny wear facets on restorations. There is an increased risk for fracture of teeth and restorations.

Figure 2. extreme attrition of teeth leading to loss of complete crown of mandibular teeth