Wednesday, March 26, 2008

Herpes Zoster (Shingles)

This patient had an apicoectomy on #4. Six days later while traveling out of town, he began to have severe pain and lesions form on his face. He came to our office for evaluation of the surgical area. As you can see, he experienced the classic outbreak of herpes zoster (shingles).

For a brief review, after initial infection with the VZV (chickenpox), the virus goes into a dormant state in the dorsal spinal ganglia. The re-activation of this virus causes herpes zoster. The reactivated virus will become apparent in the distribution of the affected sensory nerve. Zoster occurs in 10-20% of individuals, and increases with age.
As opposed to the herpes simplex virus (HSV), single recurrences are generally the rule.
Predisposing factors for reactivation of the virus include, immunosuppresion, treatement with cytotoxic drugs, radiation, malignancy, age, alcohol abuse & dental manipulation.

Clinical features begin with pain in the epithelium of the affected sensory nerve (dermatome). Typically one dermatome is affected. Prodromal pain often accompanied by fever, malaise and headache is usually present for 1 to 4 days before the outbreak of the cutaneous or oral lesions.
Involved skin will exhibit a cluster of vesicles on an erythematous base. After 3 to 4 days, the vesicles become pustular & ulcerate. Crusting develops after 7 to 10 days. The exanthem usually resolves within 2 to 3 weeks. Scarring can occur.
Pain lasting longer than 1 month following a shingles outbreak is known as postherpetic neuralgia. Most of these will resolve within a year.

Treatment for herpes zoster is mostly supportive and symptomatic. Fever should be treated with antipyretics without aspirin. Lesions should be kept dry and clean to prevent secondary infection. Topical or systemic antipruritics can be given to decrease itching. Corticosteriods have been used to minimize associated neuralgia. High dose acyclovir can decrease duration of the exanthem and severity of pain.

In this case, special consideration was given to the involvement of the eye. Proper referral to medical and dental specialists is important to prevent permanant damage to affected areas such as the eye.

Photographs used with patient's written permission.
(Source: Neville, Damm, Allen & Bouquot. Oral & Maxillofacial Pathology, 188-191, 1995)

Thursday, March 20, 2008

Research Update: Direct Pulp Capping with MTA

A recent study published in the Journal of the American Dental Association discusses the use of MTA (Mineral Trioxide Aggregate) as a direct pulp capping agent.

Up to now, MTA has been used mainly by specialists, mostly endodontists, as a restorative material for root end fillings (apico retrofills) and root perforation repair. However, new applications for MTA may put it in the hands of a wider variety of practicioners.

MTA is a bioactive silicate cement. It is essentially a medical grade portland cement. There are several properties of MTA that make it such an ideal material. It has small particle size, alkaline pH when set and slow release of calcium ions. It is known for its sealing ability. It has also been reported to induce cell proliferation, cytokine release, hard tissue formation and an interface with dentin resembling hydroxyapatite. It is non-absorbable and requires moisture to set. In short, its sealing ability, biocompatibility & hydrophilic nature make it an excellent repair material.

Endodontists have been using MTA for pulp capping, apexification/apexogenesis for all of the properties described above. The recent article by Bogen, Kim & Bakland provide evidence that supports the use of MTA as a direct pulp capping agent.

The authors selected 53 teeth that had deep caries with vital pulpal tissue and no prior restorations. Caries were removed under magnification and NaOCl was used to obtain hemostasis within a short period of time (1 to 10 min.). 1.5-3.0mm thick layer of MTA was placed over the exposure. The teeth were restored provisionally with unbonded resin restoration. At a subsequent visit, the teeth were restored with a bonded restoration.

Over a 9 year period of observation, the authors found that 49 of 53 had a favorable outcome on the basis of radiographic appearance, subjective symptoms & cold testing. All teeth (15 of 15) in younger patients with open apices showed completed root formation (apexogenesis).

Many are reluctant to perform direct pulp capping procedures due to unpredictable outcomes with traditional materials. MTA may be a more predictable and successful material for direct pulp capping teeth with a pulpal condition no more severe than reversible pulpitis.

(Source: Bogen, George, Kim, Jay, Bakland, Leif. "Direct Pulp Capping with Mineral Trioxide Aggregate", JADA 2008, 139:3, p 305-315.)

Tuesday, March 18, 2008

Fantastic Endodontic Healing

This tooth #30 was diagnosed with a necrotic pulp with chronic apical abscess. Large periapical lesion noted, 4mm pocketing, class II mobility with large subgingival/subcoronal repair. Proper diagnosis indicated that this lesion is a true endodontic lesion. Therefore, endodontic therapy should yield good results.

Endodontic treatment completed.

3 year recall illustrates complete endodontic healing.  The tooth is completely asymptomatic and functional. A new coronal restoration to include the previous repair done on the distal is recommended to prevent coronal leakage.

Monday, March 3, 2008

Golden Rules for NiTi Rotary Preparation

The introduction of nickel-titanium rotary instruments has changed the way most people practice endodontics. The use of rotary instrumentation allows an experienced practicioner to do consistent, reproducible shaping procedures on his/her patients.

As part of the AAE Colleagues for Excellence program, which produces a biannual clinical newsletter for all practicing general dentists, "Rotary Instrumentation: An Endodontic Perspective" reviews the basics of NiTi instrumentation design, prevention of fracture & clinical tips for use of rotary instrumentation.

There are over 30 different NiTi instrument systems on the market. The two main factors to consider when selecting a NiTi system are cross sectional design and tip configuration.

The biggest challenge with using rotary instrumentation is fracture of the NiTi instrument. Understanding the metallurigical properties of NiTi rotary files and some clinical "Golden Rules" are critical for success with rotary instrumentation.

The "Golden Rules" for NiTi rotary preparation are as follow:

1. Assess Case Difficulty
2. Provide Adequate Access
3. Prepare with hand files up to size #20 prior to rotary use
4. Use light touch and low RPM
5. Proceed with crown-down sequence
6. Replace rotary instruments frequently

Separated instruments can be a source of stress that can be reduced or eliminated from your practice. If you have not received the latest "Collegues for Excellence" publication from the AAE, contact your local endodontist or the AAE to get a copy.