Products and news for the dental profession June 2005 dentalproducts.net visit us online atC&B impressionsThe H&H cordless impression technique using PerfectIM Systems impression materialBy Dr. Joe Steven, Jr., Wichita, Kan. Information provided by J. Morita USA Inc.Following are step-by-step procedures for the H&Hcordless impression technique using PerfectIMSystems vinyl polysiloxane impression material. 1. Immediately following the crown preparation (Fig.1), the assistant hands the clinician a triple tray loadedwith the 30-second Blue Velvet bite registration ma-terial (J. Morita) (Fig. 2).2. Place the tray into the patients mouth and have the pa-tient close properly and tightly. Have the assistant holdthe patients chin, while the patient bites down for oneminute. Note:During this initial impression, there isno hydraulic compression at the margins (Fig. 3). 3. After the material sets, ask the patient to open, keep-ing the impression firmly seated onto the opposingarch.4. Rinse any blood or saliva from the impression in themouth and dry it (Fig. 4). 5. The assistant hands the clinician a cartridge gun thatcontains SnoWhite wash material (J. Morita).Note:Avoid injecting too much wash material into the im-pression of the prepped tooth. This doesnt have to beexact, but try to fill it about halfway full of the mate-rial. It is better to use less wash material than to over-fill it and have it flow onto the adjacent teeth. 6. Inject the material only into the area of the preppedtooth within the impression (Figs. 5 and 6) andhave the patient bite together tightly again for 1minute (Fig. 7). During this dual impression stage,hydraulic pressure causes the impression to precise-ly record subgingival margins in the presence ofblood and saliva and eliminates the need for pack-ing cord (Fig. 8).7. The assistant removes the tray, and the clinician in-spects it for accuracy (Fig. 9). Vinyl polysiloxane impression material.FeaturesAccurate final impressions of subgingival marginsNo retraction cord, gingival excision, or application of hemostaticagents necessaryTwo-step system eliminates the time-consuming task of packing retraction cord and therefore anypossible subsequent discomfortMaterials are cartridge-dispensed, radiopaque,hydrophobic, andthixotropic (exceptSnoWhite and Final Wash)PerfectIM Systems TechniqueTasteless and odorlessExceptional dimensional stabilityImmersible in aqueous disinfectantsA range of working/setting timesand viscosities is available for anyimpression procedureJ. Morita USA Inc.www.jmoritausa.com9 MasonIrvine, CA 92618888-566-7482Fig. 4Rinse blood or saliva from theimpression and dry it.Fig. 5Inject the wash material only on the area of the prepped tooth withinthe impression. Fig. 6The appropriate area of the tooth to inject the wash material.Fig. 9The completed impression. Fig. 7Have the patient bitetogether for one minute.Fig. 8How the tissue and fluids displace in patients mouth.The H&H techniqueThe H&H cordless impression technique de-veloped by Dr. Jeffrey Hoos can save any-where from 10 to 20 minutes per procedureand much more time for multiple preps.There are several advantages to this techniquethat benefit the patient and the offices bot-tom line. There is no need to stop the bleeding be-cause of thehydrophobicnature of thisvinyl polysiloxane material. It is not necessary to pack retraction cordbecause of the hydraulic pressure createdduring the dual impression technique. There is no need to use any hemostatic so-lutions that patients detest. The procedure is efficient, simple, and in-creases patient comfort, saves treatment time,and gets great results.When first trying this technique, start off witha single-unit posterior crown and test yourtechnique along with your lab technician. This technique requires more die spacingthan conventional crown techniques espe-cially at the occlusal line angles. The labtechnician must apply more die spacer (ap-proximately 40 microns), especially at the oc-clusal and axial line angles. Every lab is dif-ferent, so simply explain that their die spac-ing technique may need to be modified forH&H cases.Wait until seating the first crown beforeattempting the procedure with other patients.DPRFig. 3There is no hydraulic compression at the critical margin zone.Fig. 2Triple tray filled with Blue Velvetbite registration material.Fig. 1The prepared crown.Copyright NoticeCopyright by Advanstar Communications Inc. Advanstar Communications Inc. retains all rights to this article. This article may only be viewed or printed (1) for personal use. User may notactively save any text or graphics/photos to local hard drives or duplicate this article in whole or in part, in any medium. Advanstar Communications Inc. home page is located at http://www.advanstar.com. Reprinted from DENTAL PRODUCTS REPORT, June 2005 Printed in U.S.A.