> Draw a picture of the planned preparation outline form. --- pen, paper, patient's
　chart.
> Patient set up and discuss with instructor then　 S.I.P. --- basic set up, napkin,
　holder.
> Right I.A.N.B. --- topical, 25 gauge long needle, Octocaine.
> Rubber Dam. --- rubber dam　 #31 to #22, no.14 clamp with floss on # 31,
　floss on #22, Woodbury type frame.
> Drawing on tooth of preparation outline form --- pencil.
> Start to prepare tooth. --- always start with ideal form, high speed handpiece,
　256 bur or #257 (diameter : 1 mm).
> Start with Cl I preparation. --- minimum isthmus width 1 mm, depth:1.5 mm in
　the pit or groove area, buccal or lingual wall maybe 2 - 2.5 mm, usually to the
　DEJ.
> Dovetail, buccal and lingual walls are 90 degree or little undercut, mesial and
　distal walls are flare-out (because of the direction of enamel rod), enamel wall
　should be finished with #256 bur in one direction with painting motion, 10-4-8
　or 61/2-21/2- 9 hoes may be used to smooth floor, no bevel at the occlusal
　cavo-margins.
> The proximal box. --- #256 bur first but leave a thin ledge of tooth structure
　with adjacent tooth, use#10 H.A.(hatchet) or binangle (chisel) to remove it and
　the proximal buccal and lingual enamel lips (Do you know what I mean?), axial
　depth: 1 mm at least and 0.5 mm into the DEJ, axial length: 1.5 - 2.0 mm, the
　buccal, lingual and gingival separation with adjacent tooth: 0.20 - 0.75 mm
　(diameter of 3A explorer at the position 1 - 1.5 mm away from tip or thickness
　of IPC).
> Proximal retentive form. --- #699L or #698L bur with slow speed handpiece in
　proximal axial line angles toward buccal and lingual direction, half of tip of bur
　into dentin like a half pyramidal cone shape with its base at gingival floor
　surface and its top no higher than the pupal wall, that is to say it fades away
　from pupal floor (Do you understand? - Try to imagine it.).
> Gingival bevel and bevel on the pupal-axial line angle. --- use gingival margin
　trimmer, a 0.5 mm 45 degree bevel.
> Until now you finish the ideal class II prep. Then if there is some deep caries.
　--- use #6 (at least #4) round bur with slow speed handpiece or spoon
　excavator to circumscribe the caries 0.25 mm.
> Congratulation! You just finish the preparation. Don't forget to check it again
　to make sure every thing is fine. Then you may perform next step.
> Apply matrix. --- Tofflemire matrix, matrix retainer, wooden wedge, egg
　burnisher, the matrix must be tight,it should be tightened first and then 1/4 turn
　loose and burnished against adjacent tooth,the apex of wedge can't be over the
　gingival margin, the band positioning slots of the matrix retainer should be
　toward gingiva (So the retainer can be removed occlusally before the matrix
　band. And the band should be removed by a rotating sideways direction. Do
　you get it ?)
> Apply calcium hydroxide, varnish, liner or base. ---
　1. Shallow cavity (1.5 mm depth in pit or groove area, or just to DEJ):
　　2 layers of varnish (Copalite) is applied to reduce microleakage that occurs
　　in conjunction with the amalgam restoration. It serves as a dentinal tubule
　　sealant. But the use of varnish is still controversial.
　2. Moderate cavity (how moderate is moderate?):
　　2 layers of varnish and a thin coat (0.2-0.5 mm) of liner (varnish-type
　　materials to which calcium hydroxide or zinc oxide powder is added) to
　　provide a barrier against chemical irritation.
　3. Deep cavity (almost to pulp):
　　A thin coat of calcium hydroxide (Dycal) is applied in the deepest area (pupal
　　wall only) to promote the formation of secondary dentin. Then 2 layers of
　　varnish followed by about 1 mm thick base (ZPC, ZOE, G.I., IRM or
　　Polycarboxylate cement) to function as barriers against chemical irritation,
　　provide thermal insulation, and resist forces applied during condensation of
　　amalgam.
> Amalgam condensation. -- amalgam alloy, amalgamator, dappen dish, amalgam
　carrier, 0T diamond condenser, 1T diamond condenser, 2T round condenser,
　3T round condenser, 4T condenser, egg burnisher === 4T or 3T first to
　condense by using an overlapping or stepping method with a 6 - 8 pounds
　force, use 0T or 1T condenser in proximal retentive groove area (Choose the
　right size and right shape condenser for different area),at first the condensation
　should be perpendicular to the pupal wall until 3/4 of the preparation is filled,
　then change the direction to a 45 degree angulation towards the margins of the
　preparation, over fill by about 0.5 mm.
> Post condensation burnishing. --- egg burnisher, it should rest on the cusp slope
　beyond the margins of the preparation.
> Working time for condensation. --- 3 - 31/2 minutes.
> Carving. --- 4 -5 discoid - cleoid carver, Tanner carver, #2 knife, #29 knife,
　basic setup === 3A to begin the contouring of the marginal ridge, use discoid
　(round) to remove excess amalgam and define the occlusal amalgam margin.
　Then use cleoid (sharp) to carve developmental grooves and pits until it sounds
　squeaking. Now we can remove the retainer and matrix, then use #2 knife to
　remove the excess amalgam from the gingival and proximal margins by a
　buccolingual direction, now the marginal ridge height can be adjusted by
　carving with the discoid end or the round end of the Tanner carver until the
　original marginal height is duplicated, then the occlusal embrasure is developed
　with the #29 knife and the discoid end of the carver, finally the occlusal
　anatomy is redefined using the cleoid (sharp) end of the carver to establish
　the developmental grooves, pits and a lingual groove (sluiceway).
> Check occlusion. --- after removing rubber dam then use the articulating paper
　to check the occlusion and adjust it.
> Polishing. --- 24 hours later, basic setup, high speed handpiece, slow speed
　handpiece, prophy handpiece, prophy cup, friction burs (flame shaped white
　stone, 7802 flame shaped 12 fluted), latch type burs (#6, #4, #2, #1, #1/2
　finishing round, pear shape white stone, bud bur, brownie, greenie, super
　greenie), Sof-Lex discs and mandrel, #29 knife, #2 knife, finishing strips,
　pumice powder, Tin-oxide or Aluminum-oxide powder, alcohol, water ===
　start with the flame shaped white stone on the high speed handpiece to smooth
　the occlusal margin with light pressure and slow speed (with red dot in position
　,that is reverse rotating for polishing not cutting), marginal discrepancies in the
　groove areas can best be finished with the point of the 12 fluted bur, then the
　occlusal surface of the amalgam is smoothed using the appropriate size of steel
　finishing burs until there is no scratch, whenever possible the bur should be
　rotating from the amalgam toward the tooth, #1/2 bur and/or bud bur are/is
　used to smoothed the depths of the grooves and pit areas, then finish the
　proximal area with #2 or#29 knife and followed by a medium Sof-Lex disc, the
　disc should be rotating from the amalgam toward the enamel, after that use
　finishing strips to finish it, occlusal surface can be further finished with white
　stone, brownie, greenie, super greeniefinally use pumice powder with water in
　prophy cup to polish, pumice powder only, Tin-oxide or Aluminum-oxide
　powder with alcohol in prophy cup to polish, then powder only.
> Check it again, then show your final product to your patient.
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Topic Eight:　Why Do We Need Root Canal Therapy?

> What is pulp chamber and root canal?
　The center of the tooth is hollow. This hollow in the crown portion of the tooth
　is called the pulp chamber. In the root portion of the tooth, the hollow narrows
　to become a small canal called the root canal. The pulp　 chamber and root
　canals contain a living tissue called pulp. The pulp contains small arteries,
　veins, and nerves that have branched off an artery, vein, and nerve that pass
　through the jawbone.
> When do we need root canal treatment?
　Bacteria are the most common causes of inflammation and infection of the
　pulp. They enter the pulp through tooth decay or if a tooth breaks. Invading
　bacteria first overwhelm the pulp defenses in the pulp chamber. Then they
　destroy the pulp in the root canals. Toxins(poisons) from the bacteria that have
　destroyed the pulp can leak out of the root ends into the jawbone. Then the
　jawbone can become inflamed and infected by the presence of bacteria and
　their toxins. Finally, long-standing dental infection in bone can erode through
　the side of the bone into the mouth, or into the face or neck, to cause sudden,
　serious, and painful swelling. If leave it untreated, it may cause the advanced
　destruction of the jawbone so that you may see a radiolucence in the root tip
　area on the radiograph film. Now it is the time that we need root canal
　treatment.
> What are the goals of root canal therapy?
　1. Removes bacteria and infected pulp from the pulp chamber and root canals.
　2. Completely fill the canal(s) and pulp chamber with a solid filling material to
　　prevent future trouble. When root canal therapy is done, inflammation in the
　　bone around the root ends can heal, and the tooth is saved.
> What is the procedure of root canal therapy?
　Step 1: Opening the tooth - The dentist gently makes an opening into the tooth.
　　　　Local anesthesia may be necessary to prevent pain that can occur if
　　　　any nerve fibers are still alive in the pulp. All tooth decay is removed.
　Step 2: Shaping the canal - The dentist uses a series of very delicate, flexible
　　　　finger-held instruments.The one used in the illustration is a file. The
　　　　canals are delicately cleaned with these instruments to remove dead
　　　　　pulp debris and bacteria.
　Step 3: Filling the canals - The most commonly used filling material is a firm,
　　　　waxy, rubbery compound called gutta- percha. Several pieces of
　　　　gutta-percha are coated with a special liquid cement and then inserted
　　　　firmly into the end of the root. Wedged tightly, it completely seals off
　　　　the end of the canals so that no fluid can leak past it. The gutta-percha
　　　　will be packed to the level of the pulp chamber. Lastly, the dentist fills
　　　　the tooth with a temporary protective cement.
> Why should we restore the tooth after root canal therapy?
　Because tooth decay that was bad enough to let bacteria into the pulp usually
　has destroyed much of the crown. Cleaning and shaping the canals further
　weakens the tooth. Such a tooth may break during chewing unless repair
　includes an internal post support followed by a fully covering crown.
> What is the procedure of restoring a tooth being treated by root canal
　treatment?
　Step 1: Placing post - There are many internal post placement methods, all
　　　　requiring great care and precision. One of the methods is to insert a
　　　　stainless steel post after removing the temporary filling and about two-
　　　　　third of gutta-percha.
　Step 2: Building up core - A plastic flows into the tooth and around the post,
　　　　and is built up well above the gum. It hardens and then is shaped to
　　　　receive a crown. And sometimes a casting post and core can be built
　　　　as one piece at one time. Or a amalgam can be used as post and core if
　　　　there is not much tooth structure destroyed.
　Step 3: Finally, a crown is precision-fitted.
> Conclusion: Root canal therapy saves teeth with infected pulps. It avoids the
　complication and greater expense of replacing teeth that would otherwise be
　lost.
* This note is abstracted from "Why Root Canal Therapy?" by Joel M. Berns - Quintessence Books 1986.
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Topic Nine:　Is It Safe To Use Silver Amalgam In Dental
　　　　　　Therapy?

　The answer is absolutely "Yes". Why am I so sure about the safety of using
silver amalgam in dental therapy? Because:
1. CLASSICAL RESEARCH SUPPORT:
　There are a number of classic studies that had established the safety of silver
　amalgam to the satisfaction of the scientific community up until the findings of
　the 1980's.
　A. Souder,W. et al 1931: The results proved that mercury in silver amalgam is
　　chemically reacted and tied up within the body of amalgam restoration.
　B. Hoover,A. et al 1966: The result proved that mercury in silver amalgam did
　　not contribute to the overall body burden of mercury.
　C. Frykholm,K.O. 1957: The results indicated that there is a small but
　　measurable exposure to mercury vapor when amalgams are placed, but the
　　mercury is then excreted a few days after placement.
2. RESEARCH QUESTIONING THE SAFETY OF SILVER AMALGAM
　AND THE CRITIQUE OF ANTI-AMALGAM RESEARCH:
　A. In 1981 researchers at the University of Iowa reported that small amount of
　　mercury vapor was released from the surface of amalgam when restorations
　　when patients chewed gum. And this finding has been confirmed by other
　　researchers.
　　But:
　　a. The truth is that only a miniscule amount of mercury vapor is released
　　　intraorally when heat is generated during mastication.
　　b. As with other potentially toxic materials, a safe level of mercury vapor
　　　that can be tolerated without untoward effects has been established by
　　　industrial safety boards. That level is known as the T.L.V. or Threshold
　　　Limit Value. But the worst dose a patient could receive from 10 or 12
　　　amalgam restorations would be about 1/100th of the current T.L.V.
　　c. Berglund,A. estimated by a 24 hour study of the daily dose of mercury
　　　vapor inhaled after released from dental amalgam in 1990. He estimated
　　　the dose at 1.7 ug./day. Another researcher, Mackert,J.R., estimated the
　　　dose at 1.2 ug./day. But the normal diet of dose is 10-20 ug./day. Which
　　　means that the amount of mercury vapor a patient could absorb per day
　　　from his or her amalgams would be 1/10 to 1/20 of that which they
　　　receive from a normal healthy diet.
　B. In 1987, Nylander,M. et al reported that patients with multiple amalgam
　　restorations have slightly higher mercury concentrations in the human brains
　　and kidneys. And other researchers also proved those patients have slightly
　　higher blood mercury levels.
　　But:
　　No scientific data supports that these relatively minor elevations of mercury
　　have any demonstrable clinical consequence.
　C. Some patients report some short-term amelioration in symptomatology after
　　the removal of amalgam restorations, but, in a very subjective manner.
　　But: The truth is that this improvement may or may not be real; if real, it
　　could be a result of any one of the therapies that have been utilized, or could
　　be the result of a placebo effect. No attempt seems to ever have been made
　　to gather long-term data, nor to present that data in the scientific literature.
3. RESEARCH SUPPORTING THE CONTINUED USE OF SILVER
　AMALGAM:
　A. Brodsky,J.B. et al 1985: Using a large patient sample of women either
　　employed in a dental office or married to a dentist, the outcome of
　　pregnancy was compared to a non-dental group. The results indicated that
　　there was absolutely no difference between the two groups in any of the
　　indices evaluated (spontaneous abortion, stillbirth, birth defects, etc.).
　B. Mackert,J.R. et al 1991: The result has reported absolutely no difference in
　　white blood cell populations (including t-lymphocytes) in patients with and
　　without amalgam restorations.
　C. The A.D.A. has conducted surveys on the health of　 it's member dentists
　　for a number of years. These surveys show that American dentists are
　　slightly healthier than the general population inspite of their chronic exposure
　　to higher than normal levels of mercury vapor.
CONCLUSIONS:
1. Small amounts of mercury vapor are released from the surface of silver
　amalgam restorations during mastication.
2. The amount of mercury vapor released is very small, and poses no risk to the
　integrity of the restoration, nor to the systemic health　 of the patient.
3. There are virtually no published scientific papers validating the belief that
　mercury in silver amalgam is potentially dangerous to patients.
4. There is an ample and growing body of research that demonstrates the safety
　of silver amalgam.
5. This research plus the over 100 year history of use of the material, supports it
　is continued use. And it is the choice of filling material in contemporary dental
　treatment.
6. There's absolutely no problem for patients in regard to systemic conditions and
　the placement of silver amalgam restorations.
7. Unwarranted removal of amalgam restorations in the name of safety is wrong,
　and, in fact is considered unethical in many jurisdictions.
YES, IT IS SAFE TO USE SILVER AMALGAM IN DENTAL TREATMENT.
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Topic Ten:　Dentin hypersensitivity

Introduction:
　 Dentin hypersensitivity (hyperalgesia), shown to affect 18% of adults, is characterized by exposed dentin and demonstrated by exaggerated response to various stimuli (tactile, ch-emical, thermal, or osmotic). Epidemiologically, it has been shown to peak in the third decade of life, and peak subsequently in the fifth decade, particularly in periodontal patients.

Mechanism:
1. According to hydrodynamic theory, various stimuli displace the fluid in the
　dentinal tubules inwardly or outwardly. Fluid movement (a mechanical
　disturbance ) activates the nerve endings at the pulp/dentin interface. Thus,
　anything that decreases dentinal fluid movement or dentin permeability should
　decrease sensitivity.
2. SEM has shown that hypersensitive dentin has 8 times as many open dentinal
　tubules as nonsensitvie dentin. The diameter of open dentinal tubules in
　sensitive teeth was twice that of dentinal tubules in nonsensitive teeth. This is
　significant because most treatment modalities attemp to occlude the dentinal
　tubules.
3. Dentin covered by enamel or cementum is not hypersensitive. But a) enamel
　removed by ... b) gingival recession causes ... c) 10% of individual ... .
　　　
Natural densensitization:
　Not all exposed dentin is sensitive. Teeth desensitize naturally:
1. Dental caculus.
2. Salivary proteins and plasma proteins.
3. Intratubular crystals.
4. Secondary, peritubular and irritation (tertiary) dentin.
5. Smear layer - a film of microcrystalline debris on the root surface.
　　
Etiology:
1. Acid : a) Dentin loss greatly increases when brushing is performed immediately
　　　　　after ingestion of dietary acids; thus patients should be cautioned
　　　　　against brushing too soon after acid digestion.
　　　　b) Gastric regurgitation is one source of acid exposure.
　　　　c) Rinsing with mouthwash can result in acid exposure.
2. Poor oral hygiene : Plaque may interfere with natural occluding of dentinal
　tubules, and the acids produced may open dentinal tubules by dissolving
　mineral precipitates.
3. Improper oral hygiene techniques : Abrasive toothbrushes and dentifrices, and
　incorrect toothbrushing techniques contributed to gingival recession, loss of
　tooth structure, and dentin hypersensitivity (right-handed : left-side canines,
　premolars).
4. periodontal therapy : Dentin hypersensitivity may increase more than 100% 1
　week after treatment.
　　　
True pain syndrome:
　Dentin hypersensitivity satisfies the criteria of true pain syndrome. It is chronic
with acute excerbations. Chronic pain has a psychological component. Psychic
tension can reduce the threshold of tolerance to external stimuli.
　
Diagnosis:
　In response to certain stimuli, the pain is sharp, well-localized, brief, and
usually dissipate upon removal of the stimulus but may persist as a dull pain. D/D
includes fractured restorations, chipped teeth, dental caries, postoperative
sensitivity, and pupal abscess.

Treatment:
　Golden words by Grossman : the ideal treatment should not irritate the pulp,
nor cause pain, should be easy to perform, rapid, and efffective for long periods,
should not cause staining, and should be consistently effective.
1. Dentifrices :
　a) Long-term use, cost-effective, noninvasive, simple to use, and can be
　　applied at home.
　b) 92 % of subjects expericed relief in a well-controlled double-blind study.
　c) 5 % potassium nitrate (KNO3) > strontium (Sr) chloride > sodium nitrate.
　d) Na monofluorophosphate > non-fluoride control.
　e) Mechanism of KNO3 : It is belived to increase the extracellular K ion
　　concentration. This causes a initial action potential , but the nerve fibers
　　cannot repolarize due to high extracellular K concentration.
2. Fluorides :
　a) Sodium fluoride (NaF) is available in a variety of forms for treating dentin
　　hypersensitivity.
　b) Mechanism : NaF leads to formation of calcium fluoride (CaF2) crystals
　　which can occlude dentinal tubules.
　c) Iontophoresis enhances the effectiveness of NaF application. With
　　iontophoresis, a charged electrical current drives more fluoride ions into
　　dentin (2 ~ 6 times).
3. Oxalates :
　a) Professionally applied oxalate solutions are increasingly popular.
　b) Three types are available : 6 % ferric oxalate, 30 % dipotassium oxalate,
　　and 3 % monohydrogen monopotassium oxalate.
　c) Of the 29 desensitizing agents tested in vitro, 30 % dipotassium oxalate
　　reduced dentinal fluid flow the most(98.4 %). K oxalates combine occluding
　　properties with the inhibitory effect of K ions on nerve activity.
　d) Mechanism : Oxalate ions react with Ca to form insoluble Ca oxalate
　　crystals that occlude dentinal tubules.
　e) The effectiveness of K oxalate is short-lived. It is suspected that the oxalate
　　layer is dissolved or removed over time.
4. Dentin bonding agent :
　a) These agents have been　 used successfully to treat dentin hypersensitivity.
　b) Clinical evidence shows the effectiveness of the 4-META adhesive system
　　in treating dentin hypersensitivity.
　c) Super glue, Gluma.
5. Laser :
　a) The procedure is quick, simple, and drastically reduces sensitivity in one
　　treatment. But the use of dental laser on hard tissue isn't approved by FDA.
　b) Mechanism : Dental laser closes dentinal tubules and lased dentin is harder.
6. Restorations :
　a) If the previous treaments doesn't work, this is a good choice.
　b) This requires more time and is more expensive, but is long-lasting and more
　　predictable.
　　
Conclusion:
1. 18 % of the population suffers dentin hypersensitivity. And the prevalence is
　expected to rise.
2. Patients treated for dentin hypersensitivity should be counseled about dietary
　acids and the importance of proper, effective oral hygience.
3. Dentifrices will continue to have an important role in treating dentin
　hypersensitivity. KNO3 is the most effective.
4. Oxalate application is an effective, short-term treatment. 30 % K oxalate is the
　best.
5. Dentin bonding agent, especially the 4-META adhesive system, are moving to
　the forefront in clinical care.
6. A restoration may be indicated if loss of tooth structure is significant or the
　tooth does not respond to desensitizing treatments.
7. In the future, dental lasers are expected to have an important role in treating
　dentin hypersensitivity.
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