Primary Teeth

Teeth are a wonderfully complex part of the human body.  It is easy for most of us to overlook all of the ways that our teeth have an impact on our daily lives from birth to old age; from affecting the overall look of our face and enjoying wonderfully delicious foods, to the important role they play in helping to prevent health problems in other parts of our body, including our heart.

You may not realize it, but your baby is born with a complete set of teeth; small as they are, hidden below the gumline within the deep recesses of the jawbones. From birth until about the age of 3, you will witness the gradual eruption of 20 primary teeth, also called "baby teeth."  Primary teeth are important because they are essential in the development and eventual location of 32 permanent teeth which erupt between the ages of 6 to 13 years old.

Primary teeth maintain the spaces where permanent teeth will eventually erupt, and help with speech development and facial aesthetics.  Take good care of your child's primary teeth.  Even though primary teeth last only a few years, dental cavities and infection can take their toll, causing pain and often requiring expensive treatment.  Destruction of the primary teeth often leads to permanent space problems, shifting of the remaining teeth, speech difficulties, and possibly destruction of the permanent dentition.

Your child will generally have all his or her primary teeth by the age of 2 ½ to 3, and will keep all of them until age 5 ½ or 6, when they systematically begin to loosen and fall out.  The first primary teeth to be shed are typically the front, middle teeth on the bottom.  These are known as the primary central incisors.  The process of shedding primary teeth usually lasts until the child is 11 to 13, usually when the last primary molars and canines are lost.

It is important to properly care for your child's primary teeth because they ultimately affect the development and positioning of your child's permanent teeth.  Primary teeth serve many purposes, including:

• Chewing and Eating
• Proper Spacing & Positioning for the Permanent Teeth
• Development of the Jaw Bones and Corresponding Muscles
• Speech and Appearance
• Supporting the Gums & Soft Tissues

If your child loses a primary tooth too soon (either from injury or disease), the permanent tooth usually is not be ready to erupt into the void.  Consequently, surrounding teeth may take over the new space left by the lost primary tooth.  This can lead to eventual problems when its time for the permanent tooth to erupt.  When permanent teeth erupt out of their normal positions, this may lead to a "malocclusion," which causes teeth to become misaligned, crowded, and/or crooked. Consult our pediatric dental office if you think your child has lost a primary tooth too soon.  In many cases, future problems can be avoided by placing a space maintainer, which is an appliance that keeps the surrounding teeth from drifting into the newly formed space caused by the premature loss of a primary tooth.  Once the permanent tooth is ready to erupt into the space preserved by the space maintainer, it can be removed and the integrity of the child’s dental arch is reestablished.

It is extremely important to maintain healthy primary teeth.  If cavities are neglected and not repaired, damage to the underlying permanent tooth can result.  Proper maintenance to the primary dentition, (1.) allow for proper chewing and eating, (2.) maintain proper spacing for the eruption of the permanent teeth, (3.) provide esthetics which help the child to build confidence and self-worth, (4.) permit the normal development of the face, (5.) permit proper speech and pronunciation, and (6.) minimize the possibility of damage to the permanent dentition.   

**SHOW PRIMARY TOOTH EXFOLIATION SEQUENCE CHART**

Permanent Teeth

The first permanent molars (which are not preceded by primary teeth) begin to erupt behind the most posterior baby molar around the age of 6.  These molars are known as the “first molars,” or “6-year molars” and have a significant impact on the structure and position of all future erupting teeth and the shape of your child's lower face in later years.

Throughout your child's formative years (up and through the age of 21), the bones and muscles the face are constantly growing, shifting and changing.  Continued growth and development of the jaws and face allow for an increase of 12 additional permanent teeth.  By age 13, most children have developed a full set of 28 erupted permanent teeth, plus four unerupted teeth, called wisdom teeth, that eventually emerge behind the furthest back permanent teeth around age 18.

**SHOW PERMANENT TEETH ERUPTION SEQUENCE CHART**

Wisdom Teeth
Your child's third set of molars are no different than any other tooth, except for the fact that they are the last to erupt into the mouth.  Because they typically do so at around the age of 18 to 20 years old, when adolescents are close to turning into adults, these teeth are commonly referred to as "wisdom teeth."

People normally have three permanent molars that develop in each quadrant of the mouth; upper right, upper left, lower right, and lower left.  The first molars usually erupt into the mouth at around age 6.  The second molars grow in at around age 12, and as we previously mentioned the third molars around age 18.

Due to a lack of space within the average person, wisdom teeth don’t erupt properly, cause disruption to the adolescent’s bite, or have unhealthy gingival tissue surrounding them.  Should the individual have enough room to erupt the third molars, these teeth usually are very difficult to clean and therefore become carious. Those that do not have enough space to erupt, typically will become impacted in the surrounding bone and may become symptomatic.

Our office will begin to evaluate for the development of these teeth with the use of panoramic radiographs.  The first panoramic radiograph is obtained around a child’s sixth birthday and others every three years thereafter.  Normally the third molars begin to calcify and can be seen on an x-ray around age 9-10.  During regular semi-annual recall visits, we will continue to assess their maturation until they become symptomatic or begin to develop roots, when we would provide a referral to assess their removal.  To avoid potential problems later in life, most pediatric dentists will recommend safely removing impacted wisdom teeth once their roots begin to develop, despite the presence of symptom.  Although third molars are like any other teeth, most people continue to have normal bites and function properly in their absence.   Untreated, impacted third molars may cause secondary problems that can lead to infection, adjacent tooth resorption, gum disease, cyst formation, or even tumors.

Symptoms from impacted teeth include: Pain.   Facial swelling.   Infection in the mouth.   Swelling of the tissues around the impaction.

Dental Decay

The development of dental caries in children is governed by a complex of etiologic factors.  The relative influence of each factor is not completely understood and apparently varies considerably among individuals.  Although there is a genetic component to caries formation, heredity plays only a minor role.  Dental caries is largely an acquired disease affected by environmental conditions.  Four major factors must interact simultaneously to create a carious lesion.  They are (1.) the presence of a susceptible tooth, (2.) formation of plaque, (3.) substrate (carbohydrate or fermentable) and (4.) time.  When all of these factors present simultaneously the individual becomes predisposed to developing cavities.

Susceptible Tooth.  Obviously, the susceptible child must have erupted teeth to begin this process.  Babies are unable to develop cavities prior to the eruption of teeth, commonly between 6-12 months of age.  Beyond its mere presence, several factors will increase the particular susceptibility an individual tooth to the initiation of caries.  First, aberrant anatomical and morphologic configurations, such as deep grooves and pits and large, broad contacts between the teeth will greatly increase its susceptibility.  Second, abnormal position within the dental arch, resulting in poor alignment and crowding, will decrease its accessibility to hygiene and will allow it to accumulate quantities of plaque.  Third, deficiencies during matrix formation or mineralization resulting in hypoplasia or hypocalcification, respectively and inadequate incorporation of fluoride into the enamel surface during maturation will produce a surface texture and content less resistant to solubility and demineralization.  Last, post-eruption age is a factor because newly erupted teeth are less mature and thus more vulnerable to attack by caries.

• must have a tooth present to develop cavity
• teeth with deep pits & fissures are more susceptible to dental decay
• crowded teeth are more susceptible due to difficulties with cleaning
• deficiencies in enamel formation lead to susceptibility
• newly erupted teeth are more vulnerable to cavities

Plaque.  For any disease process, there must be not only a host but also an agent.  In the case of dental caries, the host is the susceptible tooth and the agent is cavity-causing bacteria organized in a colony termed plaque.  In dental decay, the principle offending agent in plaque formation is a bacteria known as Streptococcus mutans, which has the ability to produce a sticky extracellular polysaccharide called dextran.  Through the manufacture of dextran, these bacterial colonies are able to multiply and adhere directly to the surface of a tooth.  Newborns have been found to not have colonization of Streptococcus mutans within their oral cavities.  This bacterial invasion of the oral cavity occurs during the eruption of the primary dentition after inoculation from a caregiver, most commonly the infant’s mother.  Consumption of substrate by the Streptococcus mutans ultimately produces an acidic waste product that subsequently erodes and destroys tooth structure, causing the development of a cavity.

Substrate.  Because dental caries is a disease of bacterial origin, studies confirm that it has an infectious and transmissible nature.  However, the inoculation of cariogenic bacteria into the oral environment will not, in itself, induce caries formation.  A source of substrate must be available for the metabolism of the bacteria.  Refined carbohydrates, especially in the form of sucrose, are the substrate of choice of cariogenic bacteria.  Sucrose is metabolized by the bacteria to produce dextran.  In addition, fermentable carbohydrates, such as sucrose, are converted by the bacteria into acid.  It is this acid production that results in the demineralization process of a tooth’s protective enamel layer.  However, the process of demineralization may be initially reversed or lessened in severity by various components in saliva.  Increased salivary production and the buffering capacity of bicarbonate in the saliva will help lessen the effects of the bacterial acid production.  Other minerals within the saliva, such as fluoride, calcium, and phosphorous, contribute to the remineralization of the surface, as well.  Thus, the process of dental caries formation is chronic and influenced by the last of the vulnerable factors – time.

Time.  It is well documented that the occurrence of dental caries in children is based not on the quantity of fermentable carbohydrate (sugar) consumed but rather on the consistency and frequency of consumption.  Dietary habits, therefore, play an extremely important role.  Because the pH of plaque remains at a cariogenic level up to 30-minutes following the consumption of carbohydrates, repeated consumption in the form of between-meal snacks may result in an almost consistent assault of acid on a tooth’s surface.  In fact, a direct relationship between caries prevalence in children and frequency of between-meal snack consumption has been shown.  In addition, bedtime dietary habits have been indicted.  

Baby Bottle Decay.  In infants, the use of prolonged, non-nutritional bottle feeding or sweetened comforters such as pacifiers, particularly during sleep, can produce devastating effects on the dentition.  During sleep, the protective effect of saliva is minimal because the flow rate is greatly reduced.  The contents of the bottle (milk, juice, etc) stagnate around the teeth, resulting in rapid destruction of the upper front teeth and primary molars. Such decay is known as baby bottle or nursing caries.  Fortunately, this condition is rare (<5% in the US) and must be associated with prolonged, intense feeding practices.  Nursing caries syndrome is often a problem of overindulgence found in children of small, intact families. 

Prevalence of Decay.  Numerous studies have reported on the prevalence of dental caries in the primary dentition.  The prevalence during preschool years is of particular interest because the magnitude and impact of this disease at such a young age is a shocking revelation.  By age 3, the age at which many pediatricians recommend a child’s initial dental visit, the number of carious surfaces may range between 3-6 if the child resides in a low-fluoride area.  In general, preschool children exhibit an “all or none” phenomenon in the prevalence of dental caries in that most children appear either caries rampant or caries free.  Despite an probably not a good indicator of future caries experience in the permanent dentition, due to the multifactorial rate from the 1970’s, due to increased education and the presence of fluoride in municipal water supplies past three decades, this disease remains the most common affliction of children within our country.  Causing more missed school days than any other illness, dental decay has been found to be more than twice as prevalent as asthma.

Common symptoms associated with a possible cavity may include:

• A painful toothache.  Discomfort can be an acute sharp pain or an aching long-term chronic pain.
• Sharp pain while eating or drinking a sugary food.
• Discomfort when biting down, tapping or putting pressure on a tooth.
• Increased sensitivity to hot and/or cold liquids or foods. 
• The presence of visible brown, black or white spots.
• Visible holes in teeth.
• Tooth discoloration or shadowing.

Dental decay is one of the most common childhood diseases and is five times more common that asthma according to a report from the Surgeon General in 2000.  Although there is a higher incidence in low socio-economic populations and certain cultural groups, it is found across all segments of today’s society.  The Centers for Disease Control and Prevention reports that, “Dental decay is one of the most common chronic infectious diseases among U.S. children.  In Arizona, 35% of 3-year old and 49% of 4-year old children were found to have dental caries in a survey of pre-school children conducted by the Arizona Department of Health Services, Office of Oral Health in 1995.

Very often cavities develop and progress without any pain or symptoms.  Many types of cavities can only be detected on dental x-rays.  This is why it is so important to schedule your child for regular and routine examinations.  Routine dental visits are the easiest way to diagnose developing cavities before they begin to produce discomfort.  Typically we expect to find that a cavity is very close or even into a tooth’s nerve once regular pain and discomfort begin.  Left untreated, cavities can lead to more serious problems for your child;  severe swelling, fevers, loss of weight, ear aches, jaw pain, and odontogenic infection are a few possible symptoms associated with dental decay.  More severe consequences include facial cellulitis, difficulties breathing, eye & brain abscesses, and even possible death can occur if dental decay is allowed to progress without any professional intervention.

White Spot Lesions

White spot lesions are the earliest sign of the dental caries process on smooth enamel surfaces.  They present as areas of chalky white, opaque enamel typically seen under a layer of plaque at the border between the gum and tooth.  White spot lesions are an indication that the underlying enamel has become decalcified.  Unless steps are taken to reverse this process the lesion will likely advance to cavitation.

As previously discussed, the caries process is now understood to be a dynamic one in which the enamel mineral content may be partially lost and subsequently replaced with intact surface enamel functioning as a diffusion matrix.  Demineralization occurs when acid production by bacterial plaque produces a lowered pH.  Remineralization is facilitated by the presence of fluoride, even in very low concentrations in saliva, plaque and demineralization enamel.  The repaired fluoridated crystals are more resistant to subsequent acid attacks, as well.  The most efficient way to strengthen these white spots lesions, in an effort to prevent eventual cavitation, is to provide recurring applications of low dose fluoride.