Primary areas of tooth hypersensitivity:
- where cementum and dentin are exposed
- areas of gingival recession
- traumatic
- periodontic surgery
- Anamtomy of CEJ
- zone of dentin between enamel and cementum in 10% of teeth
- loss of cementum
- from abrasion, erosion, caries, etc.
- dentin is uncovered and dentinal tubules exposed to stimuli
- loss of enamel
- dental factors
- cracked teeth
- caries
- defective restorations w/ marginal leakage
- fractured or chipped teeth
Factors contributing to tooth hypersensitivity:
- dentin composed of calcified tissue surrounding dentinal tubules
-
tubules penetrate dentin--more tubules at surface in sensitive teeth
- in crown
and cervical areas, dentinal tubules follow "s" line for pulp to DEJ and CEJ
- in root, tubules are in straight line
- tubules at hypersensitive site have wider diamater
- tubules filled w/plasma like fluid - when tubules wider, there is constant
outflow
- bacteria from plaque can grow in open tubules, toxins can enter pulp and
cause inflammation.
4 types stimuli elicit pain response:
- mechanical (tactile)
- ex. toothbrush bristles, eating utensils, dental instruments, friction from denture clasps
/ appliances
- chemicals
- ex. acids from fermentable carbs by bacteria in plaque, citrus fruit acids, condiments
- thermal
- ex. hot or cold foods, air entering oral cavity
- osmotic
- ex. concentrated solutions (sugar, salt) on dentin surface increase fluid movement to cause pain
Importance of plaque control in treating hypersensitivity:
- bacteria from surface plaque can grow in open tubules, toxins can enter
pulp and cause inflammation
- plaque control measures can help tooth/root surfaces develop smooth, hard
surfaces with increase luster and decreased hypersensitivity
- also dentinal tubules can be blocked off by increased mineralization
- mechanical blockage for transmission of sensation created
- Modes of action:
- surface coating over tubule entrance
- intratubular mineralization of precipitation
- irritation and stimulation to encourage formation of secondary dentin
- desensitization of nerve endings.
Characteristics of ideal sensitizing agent
- fast acting
- ease of application
- biologic acceptance by body tissues
- long-lasting or permanent effects
- no side-effects- such as tooth discoloration, gingival irritation or
pulpal changes
- no pain to pt. during application
- consistent effectiveness
Agents used at home:
- plaque control -- removal from root surfaces, cervical 3rd
of tooth -- to prevent cavities and prevent hypersensitivity from bacterial
toxins and acids from cariogenic substances
- dentifrice -- with fluoride, desensitizing agent or both
- self applied fluoride -- with mouthrinse, trays/brushing
with gel
- diet-- stay away from excessive fermentable carbs
Active ingredients in desensitizing agents
- silver nitrate
- formalin
- glycerine
- calcium compounds
- fluorides
- resin
- etc.
factors to gradually lessen sensitivity
- formation of separative / secondary dentin
- deposition of fluoride and minerals at opening of tubules
- formation of calculus that covers sensitive areas
- use of diet free of pain producing foods (stay away from acidic juices,
carbonated drinks, sharp flavors, extreme hot or cold)
Treatment by professionals
- use albumin precipitants -- 40% formalin, 40% zinc chloride, 40% silver
nitrate to seal dentinal tubules
- cavity varnishes, crown and bridge cements, zinc oxide and eugenol packs
used to protect from thermal shock
- also resins with acid etch, laser and hypnosis
- stannous fluoride desensitizing paste applied to sensitive areas
Iontophoresis
- impregnation / introduction of ions of soluble salt into the body with
electrical current
- a means of applying medication with a small electrical current
Reparative dentin
- a type of secondary dentin formed along the pupal wall as a protective
mechanism
- has fewer, less regular dentinal tubules
- may form throughout life in response to extensive wear, erosion, dental
caries or restorative procedures
Hydrodynamic mechanism
- stimuli applied to dentinal tubules cause movement of dentinal fluid,
which then stimulates nerve processes in the more pulpal areas of the dentin
and / or nerves in the pulp itself
- pain impulse transmission results
Duraphat
