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Morphologic comparison of two neutral zone impression techniques: a pilot study
1School of Dentistry, St-Joseph University, Beirut, Lebanon. makzoume@inco.com.lb
The Journal of Prosthetic Dentistry
|December 8, 2004
Summary
The swallowing neutral zone technique for dentures resulted in a wider posterior area than the phonetic technique, potentially impacting premolar and molar placement. This difference was significant in the molar and premolar regions.
Area of Science:
- Dentistry
- Prosthodontics
- Oral Anatomy
Background:
- Existing research compares neutral zone and conventional denture fabrication techniques.
- Studies specifically comparing phonetic and swallowing methods for neutral zone assessment are lacking.
Purpose of the Study:
- To compare the outline form of phonetic and swallowing neutral zone impression techniques in the same individuals.
Main Methods:
- Nine participants with severe mandibular ridge resorption underwent two impression techniques: phonetic with tissue conditioner and swallowing with modeling compound.
- Impressions were standardized for occlusal height and contours traced onto graph paper.
- Measurements compared the buccolingual distance between the phonetic and swallowing neutral zones in anterior, premolar, and molar regions.
Main Results:
- The swallowing technique produced a significantly wider neutral zone buccally in the left and right molar and premolar regions compared to the phonetic technique.
- A significant lingual shift of the swallowing neutral zone was observed in the right premolar region.
- No significant differences were found between the techniques in the anterior region.
Conclusions:
- The phonetic neutral zone appears narrower posteriorly than the swallowing neutral zone.
- This difference may influence the positioning of premolar and molar teeth in dentures.
- Further research is needed to fully understand the clinical implications of these findings.