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• Deciduous teeth are also called “primary” or “baby” teeth.
• Humans have 20 deciduous teeth
• They usually begin erupting at 6 months of age and eruption is usually complete by 2-3 years of age.
• Deciduous teeth consist of incisors, cuspids and molars
• Deciduous enamel is thin so be cautious when polishing.
Deciduous Teeth
• Humans have 32 permanent teeth including incisors, cuspids, premolars and molars.
• Permanent teeth that replace primary teeth are called “succedaneous” teeth.
• Permanent incisors and cuspids replace primary incisors and cuspids so are “succedaneous”
• Permanent premolars replace primary molars and are also succedaneous.
Permanent Teeth
“Nonsuccedaneous”
• Permanent molars are “nonsuccedaneous” because they come in behind primary molars.
• The first permanent teeth to erupt are usually the mandibular first molars.
Terminology Review
• The part of a tooth covered by enamel, the hardest substance in the body, is called the “anatomic” crown of the tooth.
• The roots of a tooth are covered by cementum, a material much softer than enamel.
• The “clinical” crown is that part of the tooth showing in the mouth.
• Sometimes the “clinical” crown may include some of the root if there is recession.
• Do not polish the exposed root with the same pressure as enamel. Cementum covering the roots will be destroyed!
Beware !!
• The “clinical” crown may also be just part of a newly erupting tooth.
• Polish it very gently. It takes some time for the enamel to attain its full hardness.
Terminology Review
• The anatomic crown is separated from the roots by the “cementoenamel junction” (CEJ)
• The inside of the crown and the roots is composed of dentin which contains live tissue.
• In some patients, the tooth’s dentin is exposed at the CEJ causing sensitivity.
• Ask your patients if they have any sensitive areas before polishing and avoid those areas if possible.
CEJ
• The crown of a tooth has three parts, an incisal 1/3, a middle 1/3 and a gingival 1/3.
• The gingival 1/3 of a crown usually has the most plaque, so be sure to polish that area thoroughly.
Gingival 1/3
Middle 1/3
Incisal 1/3
• If a patient’s gingiva is healthy, it attaches to the tooth at the CEJ.
• This attachment is at the bottom of the trough or “sulcus” that circles the tooth.
• In a healthy patient, the sulcus is 1 – 3 millimeters deep.
Keratin • Tissue in the mouth that is constantly
rubbed builds up “keratin”, a material much like a callous.
• Examples of “keratinized” tissue include the hard palate, the top of the tongue and the gingiva.
• “Nonkeratinized” tissue includes the floor of the mouth and the lining of the sulcus.
• When polishing, be sure the rubber cup goes gently into the sulcus.
• Be careful, the tissue lining the sulcus is nonkeratinized, and the attachment at the bottom of the sulcus is fragile.
Other terminology • Tooth surfaces facing the cheek are
called buccal surfaces.
• Tooth surfaces facing the tongue are called lingual surfaces.
• Tooth surfaces facing the front of the mouth are called mesial surfaces.
• Tooth surfaces facing the back of the mouth are called distal surfaces.
• Occlusal surfaces are the chewing surfaces of posterior teeth
• Incisal surfaces are biting surfaces of anterior teeth.
lingual buccal
distal
mesial
distal
mesial
mesial
distal
• Two tooth surfaces that contact each other (mesial and distal) are called “proximal” surfaces.
• The triangular space on either side of the contact formed by the two proximal surfaces is called the “embrasure”.
lingual buccal
distal
mesial
distal
mesial
mesial
distal
embrasure
• The imaginary line that separates two of a tooth’s surfaces (say, mesial from buccal) is called a “line angle”.
• When polishing, it is important to “roll” the rubber cup around the line angle into the embrasure so the proximal surface is polished.
occlusal
mesial Line angle
• The purpose of flossing your patient during coronal polishing is to remove plaque and excess polishing paste from the proximal surfaces.
• If contacts are tight, be careful! Floss could injure the papilla.
More Terminology
• The indentation on the lingual surface of maxillary incisors is called the “lingual fossa”.
• It is sometimes difficult to polish so spend a little more time on these teeth.
• Occlusal and lingual pits and grooves are also difficult to polish with a rubber cup.
• Use a toothbrush, if necessary, to clean these areas, but you can’t use a rotating brush Occlusal pits
and grooves Lingual Groove