Effect of different processing techniques of denture bases on the supporting structures of maxillary implant retained overdentures

Objectives: This study was conducted to evaluate the effect of two different processing techniques of denture bases on bone height changes in implant retained maxillary overdenture.
Materials and methods: Fourteen completely edentulous patients were recruited to participate in this study. Inclusion criteria: These patients had adequate bone in the maxillary arch to receive four hybrid implants, exhibited angle class I ridge relationship and adequate inter-occlusal space. Exclusion criteria were: V shaped edentulous ridges, patients with neuromuscular diseases and temporomandibular joint disorders, diabetic and smoking patients. Patients were randomly divided into two groups. Group I: Seven patients received a maxillary implant retained overdenture fabricated from (PMMA) base processed by the compression mold technique.
Group II: Seven patients received maxillary implant retained overdenture fabricated from thermoplastic biocompatible base processed by the injectable mold technique. All patients received conventional mandibular complete dentures. Bone height around dental implants was measured after insertion, 6 months, and 12 months post-insertion.
Results In this study, bone height changes around dental implants for group I and group II at the first follow up period were 0.56 mm and 0.49 mm respectively, however, at the 2nd follow up period (6-12 months), they were 0.41mm and 0.34 mm consequently. There were no statistically significant differences between the studied groups regarding the average bone loss around the dental implants as as shown by independent t-test.
Conclusion Injection and compression molded processing techniques have similar effects on bone height changes in maxillary implant-retained overdentures.