Dental Caries-Part 4: Dentine Caries

Normal Structure of Dentin

Dentine is the part of the tooth that is covered by enamel and covers the pulp tissues. It comprises of inorganic hydroxyapatite 45-50%, organic matrix 30% and water 25%.

It is a vital tissue as opposed to enamel. It is elastic and permeable. Therefore, it is never possible for a restorative material to create a totally hermetic seal between itself and the cavity wall.

Dentine consists of dentinal tubules, peritubular dentine and inter tubular dentine. Dentinal tubules contain extensions of the odontoblast cells that line along the inner surface of the dentine and remain in the pulp. The peritubular dentine makes the walls of the dentinal tubules, are devoid of collagen matrix and are highly mineralised. The inter tubular dentine is the main structural component; present between the dentinal tubules; consists of hydroxyapatite crystals lying in the collagen matrix. 

Dental Caries-Part 3: Enamel Caries

 

Clinical and Histological Features of Dental Caries

Now we shall describes the clinical features of carious lesions on smooth,

occlusal, and root surfaces.  We shall relate the clinical features to their histological

features. We shall consider Enamel and Dentine together, the reasons being:

1. As a clinician, you will see them in the same way.

2. You can not understand changes in dentine during caries progression and caries arrest without considering the spread of the enamel lesion.

3. Changes in Dentine occur before the enamel lesion cavitates. Removal of the biofilm will arrest the lesion in dentine as well as the lesion in enamel.

4. The lesion, in both enamel and dentine, entirely reflects the activity of the bacterial biofilm.

Before I start talking about the clinical and histological features of dental caries, You must know the 

Basic Structure of Enamel

Sound enamel consists of crystals of hydroxyapatite packed tightly together in an orderly arrangement which is known as enamel prisms. The amount of hydroxyapatite ranges between 86 to 95%; the organic component between 1% to 2 % and water between 4% to 12% by volume. The total inorganic content of enamel ranges between 95% to 98% by mass, thats why it looks like crystals.

The crystals are so tightly packed that the enamel gets a glass-like appearance and appears translucent. This is the reason that it allows the varying degrees of yellow colour of the dentine to shine through it. Here, you should know that even though the crystal packing is very tight, each crystal is actually separated from its neighbours by tiny intercrystalline spaces or pores. These spaces are filled with water and organic material. When enamel is exposed to acids produced in the microbial biofilm, mineral is removed from the surface of the crystal which shrinks in size. Thus, the intercrystalline spaces enlarge and the tissue becomes more porous. This increase in porosity can be seen clinically as a white spot.

Dental Caries-Part 3: Video series

Lecture Series on Dental Caries

To watch video lectures, click at the following links

1. Introduction

2. Etiology of dental caries

3. Bacterial plaque in dental caries

4. Microbiology of dental caries

5. Sucrose and dental caries

6. Acid production in dental plaque

7. Saliva and dental caries

8. Early enamel caries

Dental Caries-Part 2: Treatment Planning

In this chapter, you will know about the treatment planning of dental caries. In previous chapter you studies the etio-pathogenesis and clinical characteristics of dental caries. If you have not gone through it, it is advised that you study the previous chapter before proceeding further.

Mechanism of Remineralisation of Enamel

When the oral environment of a person is favourable where the pH is above 5.5 and saliva contains enough calcium and phosphate ions, the remineralisation process of enamel occurs. The supersaturated saliva acts as driving force for remineralisation. In a non cavitated enamel caries lesion, the original crystalline structure of rods remains intact. When it is etched, it acts as nucleating agent for remineralisation. When trace amount of fluoride ions is added to the environment, it enhances the remineralisation process by enhancing the precipitation of calcium and phosphate. The inclusion of fluoride ions results in the formation of fluorapatite crystals in enamel rods which is more resistant to acid attack compared to calcium apatite of the natural enamel rods. Thus, the new enamel becomes resistant to caries process. 

Dental Caries-Part 1: Etio-pathogenesis and Clinical Features

This lesson presents basic definitions, terminologies, etiologies, demineralisation-remineralisation of enamel and clinical characteristics of the caries lesion in the context of clinical operative dentistry. 

Definitions of Dental Caries and Dental Plaque 

Dental caries is defined as a multifactorial, transmissible, infectious oral disease caused primarily by the complex interaction of cariogenic oral flora (biofilm) with fermentable dietary carbohydrates on the tooth surface over time.

Dental plaque is a gelatinous mass of bacteria adhering to the tooth surface. Carious lesions occur only under the plaque. The plaque bacteria metabolises the refined carbohydrate (sucrose mainly) for energy production and produces organic acids as a by product. These acids cause dissolution of crystalline structures of enamel that result in caries lesions of the tooth.  

Seven Ways to Prevent Dental Caries in Your Child

Dental caries is an endemic disease in children. It is caused by a bacterial infection. The causative bacteria are known as Streptococcus Mutans and Lactobacilli.

Although the dental caries is caused by bacteria, the initiation and progression of dental caries depend on several factors. The less the risk factors present, the less are the chances of dental caries development in your child’s tooth.

I shall discuss those factors for you so that you can understand the developmental process of dental caries and take appropriate measures to prevent developing it in your son’s or daughter’s mouth. Broadly, we can categorize a child belonging to either high risk or low risk category. The children of high-risk category have higher chances of developing dental caries compared to those of lower category.

The rampant caries develops rapidly in young children and involves all anterior teeth within a very short period. Early intervention may prevent its development. So, my advice to you, visit a dentist when you see his/her first tooth. 

Sign of rampant caries: Note caries in all teeth 

The factors that determine the risk category of a person are as follows: 

1. Social factors 
2. General Health Factors 
3. Dietary factors 
4. Preventive Factors 
5. Plaque factors 
6. Salivary factors 
7. Clinical factors 

  

1. 1. Social Factors 
   

   A socially deprived or isolated child with frequent snacking habit, irregular dental visits, siblings having dental caries, with parents having little knowledge of dental disease, will be at higher risk of developing dental caries compared to the child who is not having the above-mentioned factors. You should always try to remove and maintain these factors at low level to keep your child in low category. 

2. 2. General Health Factors 
   

   If your child is medically compromised, disabled, having xerostomia or on long term cariogenic medicine, s/he is at higher risk of developing caries. The lesser number of factors present with your child, the risk of developing dental caries is less. If your child is having any of these factors, help him/her to remain in the low-risk category by visiting a dentist. 

3. 3. Dietary Factors 
   

   The most important factor is frequent intake of sugars. As the frequency of sugar increases, the risk goes up. So, encourage your child to reduce the frequency of sugar intake. For example, you can give him/her two chocolates/candy instead of one and encourage him/her to eat them all together. Afterwards, you can clean his/her teeth off of sticky chocolates/candy. 

4. 4. Preventive Factors- Uses of Fluoride/CPP-ACP 
   

   If your child is living in a non-fluoridated area, with no fluoride supplementation and using non-fluoridated toothpaste, s/he is at high risk. Living in an area supplied by fluoridated water, or using fluoride supplement or using a toothpaste containing fluoride decreases the risk of caries development. 
   The newly developed protective material Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), a milk derivative helps in remineralization of the carious lesion by replenishing lost minerals like calcium, phosphate ions into the tooth structure. Using a toothpaste containing CCP-ACP will remineralize the enamel of your child and make it more resistant to caries development. 

5. 5. Plaque Control Factors 
   

   If your child does infrequent or ineffective tooth brushing s/he is at higher risk. Teaching him or her regular and effective tooth brushing to remove plaque. This habit decreases the risk of developing tooth decay. If s/he cannot perform effective tooth brushing, help him/her. 

6. 6. Salivary Factors 
   

   Low flow of saliva, low buffering capacity of saliva and higher Streptococcus Mutans and Lactobacilli count in saliva put your child in a high-risk category. Removing these factors with the help of a dentist will shift your son/daughter into the low-risk category. 

7. 7. Clinical Factors 
   

   New carious lesions, premature extractions, caries or restorations (fillings) in anterior teeth, multiple restorations, history of repeated restorations, no fissure sealants, multi-band orthodontics and presence of partial dentures increase the risk of caries development and put the child in high risk. As these factors decrease, the child moves from high to low-risk category.

8. 
   

Conclusion 

So, now you know the causes that may put your child at high risk for developing dental caries. I advise you to understand these factors and take appropriate action. The first step you must take is to start using a toothpaste that contains either fluoride or CCA-ACP. Also, plan for and have your child get checked by a dentist. 

Oral Malodour / Foetor / Bad Breath / Halitosis

Halitosis is a common social condition that affects a considerable portion of the general population. The prevalence of halitosis is close to 50% in a few populations. Under few circumstances, this oral condition may cause embarrassment, depression and make relationships more difficult. Some studies have investigated whether the psychology of the patients might have some influence on the complaints about halitosis, or even on halitosis itself. In a study that included more than one thousand participants and self-reported halitosis, scientists have reported that poor oral hygiene and general anxiety are associated with halitosis.[1]

Halitosis is divided into intraoral, extraoral, pseudohalitosis and halitophobia. Intraoral halitosis, responsible for 85% of the cases of halitosis, is subdivided into physiologic (genuine) halitosis or pathologic halitosis. Extraoral halitosis occurs when malodor appears with no oral cause, as in the case of pulmonary causes. Both patients with pseudohalitosis and halitophobia present with complaints of halitosis, but without any diagnostic evidence of malodor.[1]

The most common cause of oral malodor is the poor oral hygiene. Due to poor oral hygiene, a large number of bacteria belonging to different species make their home in the mouth. They survive on the food particles entangled in between the teeth and as a by-product, produce different substances like Sulphides, Mercaptans and Amines in gas form. These gases are perceived as bad breath by other people.  

Basic Reason of Fear in a Four Years Old Child Who is Aggressive in Dental Office

The quality of dental treatment of a child depends on one's cooperation and repo with a dentist in the treatment room. How a dentist manages a child depending upon the understanding the child's behaviour pattern.  

There are certain guidelines that are useful in helping a child to show a positive & compliant behaviour while getting the dental treatment. These guidelines have been prepared from the findings and principles of behavioural dentistry, behavioural psychology, developmental psychology, and paediatric psychology. 

Can Alginate Be Used As Muco-Compressive Impression Material?

The alginate impression material cannot be used as muco-compressive material. This material does not have consistency enough to apply pressure on mucosa. Therefore, muco-compressive impressions cannot be taken by alginate.

The muco-compressive impression can only be taken by impression compound or heavy duty (putty) rubber base impression materials as they both have thick consistency.

What is best during placement of Crown?

A ceramic crown being placed over a tooth. The excess cement is protruding at margin [1].

The placement of crown is an important step in the longevity of the crown and the comfort of the patient. There are certain points that should be taken into consideration by a dentist during placement i.e. cementation.

The gingival margins should not be inflamed at the time of crown cementation. This may happen due to gingivoplasty or crown lengthening. For a common man, it means, the gum margins of the tooth receiving the artificial crown should not have redness, swelling or puffiness. If there is any, better to wait till it subsides.

The choice of cement/luting agent should be decided based on the type and material of the crown. The available materials are Zinc phosphate, Glass ionomer, Polycarbonate, Zinc silicophosphate, and resin luting agents. The anterior crowns need different cementing material than that of posterior crowns. The all ceramic crowns are best cemented by resin luting agents, but the use is limited to the cementation of anterior crowns. The reason is, after cementation, it becomes extremely difficult to remove set resin from the interproximal area of posterior teeth. Rest luting materials are brittle enough to break and remove, therefore, they can be used in all areas-anterior as well as posterior.