Wednesday, March 30, 2016

The Longevity of amalgam versus compomer/composite restorations in posterior primary and permanent teeth: Findings from the NE Children’s Amalgam Trial

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: Nicholas Paquin                                                                           Date: 03/30/2016

Article Title: The Longevity of amalgam versus compomer/composite restorations in posterior primary and permanent teeth: Findings from the NE Children’s Amalgam Trial
Author(s): Jennifer Soncini, NancyNairi Maserejian, Felicia Trachtenberg, Mary Tavares and Catherine Hayes
Journal: JADA
Date: June 2007
Major Topic: Longevity of different restorations
Type of Article: Randomized Control trial
Main Purpose: To determine when amalgam or composite restorations are better long term restorations
Key Points/Summary:
- Resin-based composite restorative materials are a common alternative to amalgam. The ADA council on scientific affairs concluded that both amalgam and resin-based compomer/compistre materials are safe and effective, however there is controversy to which material is more durable.
-Amalgam and resin based materials have very different physical and functional properties.
-Amalgam – used for more than 150 years, a mixture of mercury and silver allow powder that solidifies at mouth temperature. It is moderately tolerant to moisture. It is biocompatible and durable in load bearing areas. It’s not aesthetic, and some controversy still exists about the safety of amalgam.
            -Adequate retention of amalgam in posterior primary teeth may be difficult given the difference in tooth structure (thinner enamel and dentin, shallow pits and fissured, narrow occlusal tables and enamel rods that run in the occlusal direction)
-Compomers – introduced in 1990’s are polyacid-modifier resin=based composites that contain strontium fluorosilicate glass. It can attract moisture which triggers a reaction to release fluoride and buffer acidic environments. Can be aesthetic
-Resin-based composites – nano composites have both high filler particles to provide strength and small filler particles to provide polishability. Micromechanical bonding requires a well isolated field. Less tooth structure need be removed, often why it is recommended over amalgam.
            - Some research have cited marginal leakage caused by polymerization shrinkage as a major problem.
-When choosing a restorative material, the dentist should consider longevity because replacement is a burden to patients, practitioners, and the health care system. Recurrent caries is often cited as the most common reason for replacement of restorations in primary dentition and young permanent dentition.

-Methods: Randomized children age 6-10 who had 2 or more posterior Occlusal carious lesions in groups that received amalgams (267) or compomer/composite (267) restorations and followed them up every 6 months. They compared longevity of restorations placed on all posterior surfaces using random effects survival analysis.

-Results:  Avg follow up was 2.8 +/- 1.4 years for primary tooth restorations and 3.4 +/- 1.9 years for permanent tooth restorations. Primary teeth – replacement rate 5.8% compomers vs 4.0% amalgams. 3% vs 0.5% due to recurrent caries. Permanent teeth – replacement rate 14.9% composites vs 10.8% amalgams. Repair rate 2.8% and 0.4% respectively.

-Conclusion: The overall differences in longevity is not statistically significant, but compomers were replaced significantly 7x more frequently due to recurrent caries, and composite restorations required 7x as many repairs compared to amalgams.
Clinical considerations – for posterior compomer/composites, replacement may be required at higher rates than amalgam

The Dentist's Exposure to Elemental Mercury Vapor During Clinical Work with Amalgam

Resident’s Name: Semantha Charles      Date: 03/30/2016
Article Title:  The Dentist's Exposure to Elemental Mercury Vapor During Clinical Work with Amalgam
Journal:  Acta Odontol Scand (53):44-48, 1995
Autor: L. Pohl and M. Bergman
Main Purpose:This study’s aim was to evaluate exposure to mercury vapor by means of a continuous measurement device while using various dental suction devices. All experimental data were collected during routine clinical work in a public dental health clinic. 

Key Points

The dentist’s occupational exposure to mercury vapor occurs to a large extent during cutting, filling, and polishing operations.   Previous studies used intermittent sampling with “mercury vapor sniffer equipment” that had made it difficult to properly evaluate experimental data about measuring mercury vapor during clinical operations. In the present study it was possible to measure continuously the amount of mercury in the breathing zone of the dentist during cutting, placing, and polishing of amalgam restorations. Previous in vitro studies indicated that rapid changes of mercury vapor levels will occur, especially during the cutting of amalgam. 

Fifty amalgam fillings were removed (mainly due to secondary caries but a “few” because of technical defects) and replaced with new amalgam fillings. An additional 30 fillings were polished. Three kinds of suction were used: high volume evacuation (HVE), saliva extractor (SE), and a mirror-evacuation (ME) which is a combination of a dental mirror and suction device with an evacuating capacity. The mercury vapor was sampled and measured by means of a measuring system based on atomic spectrophotometry that had a plastic sampling tube attached to the dentist’s glasses to allow for continuous measurement. Seven different measurement series were performed were the amount of vapor was measured with different combinations of cutting and/or filling and/or polishing with HVE, SE, and/or ME.  

The results showed that the maximum amount of mercury vapor collected in the “breathing zone” of the dentist was during cutting and filling with new amalgam with SE alone. If only a saliva extractor is used during cutting per se, high mercury vapor levels may be attained.  When HVE was using during cutting, filling, and polishing, the mean mercury vapor levels were 1-2 ug/m3 (acceptable short term exposure, STE, is 150 ug/m3 in a 15 minute period).These levels are not exceeded during the polishing of amalgam, even without the high volume evacuator, provided water coolant is used.   The authors conclude that in order to minimize a dentist’s exposure to mercury vapor during clinical work, a conventional high volume suction evacuator must be used.

A good article that illustrates the basis for and importance of mercury hygiene.  A good resource to reference to alleviate patient concerns about mercury exposure.

Tuesday, March 29, 2016

Reversal of soft-tissue local anesthesia with phentolamine mesylate in pediatric patients

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: Amir Yavari                                                                                   Date: 03/30/2016

Article Title:
 Reversal of soft-tissue local anesthesia with phentolamine mesylate in pediatric patients
Author(s): Tavares M, Goodson JM, Studen-Pavlovich D, Yagiela JA, Navalta LA, Rogy S, Rutherford B, Gordon S, Papas AS
Journal: JADA
Date: 2008
Type of Article: Clinical trial
Main Purpose:
The authors evaluated the safety and efficacy of a formulation of phentolamine mesylate (PM) as a local anesthesia reversal agent for pediatric patients.

-       %16 of 4 -7 year-olds and %13 of 8 to 11 year-olds reported having postoperative soft-tissue trauma after mandibular anesthetic blocks.
-       PM is a nonselective, competitive, α-adrenergic antagonist that has been used to reverse the effects of extravasation of adrenergic agonists such as epinephrine. It is a vasodilator and has blocked the effects of endogenous vasoconstrictors in the oral tissues of cats(dental pulp and oral mucosa).

-       A total of 152 pediatric subjects received injections of %2 Lido with 1:100k epinephrine. The authors then randomized subjects to receive a PM injection or a control injection in the same sites as the local anesthetic was administered in a 1:1 cartridge ratio after the procedure was completed. Over a 2-4 hour period, they measured the duration of soft-tissue anesthesia and evaluated vital signs, pain and adverse events.

-       The median recovery time to normal lip sensation was 60 minutes for the subjects in the PM group versus 135 minutes for subjects in the control group.
-       No differences in adverse events, pain, analgesic use or vital signs.

-       The proposed mechanism of action of PM: Increased local blood flow accelerates the clearance of local anesthetic from the sub-mucosal tissue to the bloodstream.
-       When PM injections are administered after Lidocaine injections, the maximum plasma concentration of Lidocaine increases (consistent with the proposed mechanism).
-       What are the side effects of PM?

-       PM was well tolerated and safe in children 4 to11 years of age.
-       It accelerated the reversal of soft-tissue LA after a dental procedure in children 6 to11 years of age.

Clinical Implications:
-       PM can help dental clinicians shorten the post-treatment duration of soft-tissue anesthesia and can reduce the number of post-treatment lip and tongue injuries in children.
Assessment of Article:  Level of Evidence/Comments: Level II

Preformed metal crowns for primary and permanent molar teeth: review of the literature

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: John Diune                                                Date: 3/30/16

Article Title: Preformed metal crowns for primary and permanent molar teeth: review of the literature
Author(s): Ros C. Rnadall, PhD, MPhil, BChD (employed by 3M ESPE – manufacturer of PMCs)
Journal: Pediatric Dentistry
Date: 2002
Major Topic: Restorative Dentistry
Type of Article: Literature Review
Main Purpose: Carry out extensive literature review on use and efficiency of preformed metal crowns (PMCs) for primary and permanent teeth
Key Points/Summary:
Purpose: Carry out extensive literature review on use and efficiency of preformed metal crowns (PMCs) for primary and permanent teeth
Method: MEDLINE search using keywords: stainless steel crowns, preformed metal crowns, primary molar crowns, permanent molar crowns
-          Inclusion criteria: 1) indications for use, 2) placement technique, 3) risks, 4) longevity, 5) cost effectiveness, 6) untilization
-          83 papers retrieved that fit criteria
Indications for Primary molar teeth:
-          After pulp therapy
-          Restoration of multi-surface caries and patients with high caries risk
-          Primary teeth with developmental defects
-          Where an amalgam is likely to fail
-          Fractured teeth
-          Teeth with extensive wear
-          Abutment for space maintainer
o   Inability to fit one: amount of tooth remaining and behavior
o   Teeth exfoliating within 6-12 months
Indications for Permanent molar teeth:
-          Interim restoration of broken-down or traumatized tooth until definitive restoration or orthodontic status established
-          Financial considerations a concern – can be used as medium-term, economical restoration
-          Teeth with developmental defects
-          Restoration of partially erupted permanent molar needing full coverage
Placement procedures (tid-bits):
-          All line angles are rounded
-          Preformed metal crowns not close fitting except for margin – so coronal preparation does not need to be precise
-          To obtain retention crown must seat subgingivally to depth of about 1mm
-          Blanching is inevitable
-          Crown that is 1-1.5mm high is acceptable for primary teeth, can spontaneously adjust for occlusal discrepancy over a week or so
Selection of crown size:
-          Restore contact areas
-          Restore occlusal alignment of prepared tooth
Crown modification:
-          After trimming, crown should be crimped to regain retentive contour
o   Margins should e thinned and smoothed, final polishing with rubber wheel and then mop and jeweler’s rouge (reduce corrosion and thus possible allergic reactions to high Nickel containing PFCs)
Crown adaptation in special cases:
-          Multiple crowns in same quadrant – adjacent proximal surfaces should be reduced more than usual to facilitate placement
-          Mesial and distal aspects of crown may need to be flattened with pliers to accommodate loss of arch length
-          Also with space loss further reduction buccal-lingually (not proximally) may be needed to fit a smaller crown than normal
-          Perforations due to wear can be repaired with composite or resin-modified glass ionomer
-          Crown should be maintained under pressure once seated onto prepared tooth while cement sets
Tooth Preparation:
-          Future preparation needs for a cast restoration kept in mind during treatment
-          1.5-2mm occlusal reduction needed
-          Buccal and lingual tooth walls may be prepared with slight taper, or not reduced at all
Crown modification:
-          Should establish good contact with neighboring teeth
-          Snap into place cervically – cervical crown margins should be recrimped after adjustment
-          Margins should be polished to high shine and adapted well for periodontal health
-          CAN NOT be left in hyper-occlusion
-          Bitewing radiograph recommended at final try-in stage to check marginal fit
-          Murray and Madden describe technique – occlusal surface of PFC removed, then cemented, followed by placement of bonded amalgam core to build up occlusal surface
Periodontal concerns
-          Summary – unexceptional plaque accumulation and frequency of gingival problems associated with SSCs
-          Well adapted crown margin actually good for oral hygiene and gingival health
-          Gingivitis can occur if margins not well contoured and/or cement present
Nickel Allergy
-          Contemporary SSC’s 9%-12% nickel (similar to ortho bands and wires)
-          Discontinued nickel-chromium crowns had about 70% nickel content
-          Greater attention is being paid to esthetics
-          Well-known method of improving appearance was cutting window into crown and placing composite resin
Longevity of PMCs:
-          Many articles cited showing higher success and/or longevity of restoration with PMCs
-          Recent meta-analysis (Randall RC et al JADA 2000) indicated that there is a selection bias for use of PMCs for restorations of teeth with largest caries lesions, and amalgam for teeth with less extensive caries

Cost effectiveness and utilization of preformed crowns
-          3 papers cited
1)      Braff – over avg 2.6 years – cost/month PMCs $0.94 vs amalgam $1.34
2)      Eriksson et found 1/5 PMC group needed further work vs 2/3 amalgam
3)      Levering and Messer used “cost unit” (CU) as standard stating that PMC (including cost of pulpotomy) was 3 CU’s and for amalgam 2 CU’s
-          Using Table 1 above for basis of calculating cost effectiveness estimate average failure rate for amalgam is 4X that of PMC
o   Assume 26% failure and $55 for Class II amalgam
o   Assume 7% failure and $91 for PMCs
o   Thus replacement cost for amalgam group would be 2.2X more than PMC group
Assessment of Article:  Level of Evidence/Comments:


Wednesday, March 23, 2016

Restorative Dentistry for the Primary Dentition (3-6 years)

Department of Pediatric Dentistry
Lutheran Medical Center

Resident’s Name: John Kiang                                                                                                Date: 3/23/16
Article Title: Restorative Dentistry for the Primary Dentition (3-6 years)
Author(s): Cassimassimo  
Journal: TEXT Pediatric Dentistry
Date: 5e
Major Topic: Restorative Dentistry
Type of Article:  Randomized Clinical Trial
Main Purpose: To discussed restorative dentistry techniques using amalgam and composites.  

Key Points:
·      Instrumentation and Caries removal:  There is some evidence that air coolant (without water) alone may be used without creating irreversible pulpal damage; Different types of instruments: Air abrasion (2k-5k) – absence of vibration and noise, caries excavation without anesthesia. Best used for adhesive restorative materials (minimal preps); Lasers (30-60k) – used for soft tissue, caries prevention, caries diagnosis, biostimulation, and pain control, hemostasis, and cavity preps. Good bc no vibration/noise, no anesthetic, minimally invasive, clean preparations (no smear layer), good for adhesive restorations; Chemochemical: noninvasive, eliminates infected dentin via a chemical agent by means of dissolution, doesn’t require anesthesia, preserves sound tooth structure, relies on bonded materials for restorations but requires more operative time.
·      Primary tooth anatomy: thinner enamel and dentin, larger pulps, enamel rods of the gingival third in an occlusal direction from the DEJ, more bulbous, broad flatter contacts, teeth are whiter, relatively narrow occlusal surfaces.
·      Use a RD whenever possible
·      Amalgam restorations: Discussed Class I ( minimal depth 1.5mm, no unsupported enamel, sharp cavo-surface margins, condense well and burnish, don’t over carve or under carve) and II restorations (proximal box should be broader at cervical portion than occlusal, buccal, lingual and gingival walls should break contact, round pulpal axial line angles as well as all other internal line angles, matrix well placed below and wedge, etc) Fracture of the isthmus of a class II amalgam is a common problem
·      Finishing/polishing amalgam demonstrated no significant difference in marginal integrity between carved and burnished-only and polished restorations.
·      5-year study comparing composites and amalgams, reported that both materials were satisfactory over the time period and the only sig statistical differences were a poorer marginal integrity for amalgam and a greater wear rate for resin.
·      Amalgam demonstrated fewer failures than resin based comps, particularly in three or more surfaces (recurrent decay 3.5 times greater in comps than amalgam).
·      PRRs now called CAR – conservative adhesive restoration (into three types 1- sealant type with widening of pits and fissures 2. Extends into dentin using wear resistant comp and excess is flowed into remaining pits and fissures 3.  Into dentin and wear resistant comp is used in preparation and sealant is used for remaining pits and fissures.