1. Introduction Objectives
The effect of mandibular implant overdenture on the volume of
premaxillary bone beneath complete denture
Mohamed Samih ALsrouji ¹ , Rohana Ahmad PhD candidate, University of Technology- MARA.
Several results have been published regarding premaxilla bone remodeling beneath complete denture opposing mandibular implant retained overdenture.
All the previous outcomes depended on 2D radiographs or models measurements and both of these methods have several limitations such magnification, position of the patient, shrinkage and expansion of the impression material and dental stones. These limitations may affected the outcomes. To avoid the previous limitation, this study developed a novel 3- dimensional technique to quantify the premaxilla bone remodeling with a more accurate outcomes. Furthermore this technique provides a clear visualized map of bone changing regions. The developing of this technique depends on a study performed on mandible (Ahmad, 2013).
Introduction
study
Premaxilla change
method
Kelly 1972
0.43 mm
Cephalometric radiograph
Crumad & Rooney 1978
0.6 mm
Panoramic radiograph
Jacobs et el 1993
Lateral cephalometric
Kreisler et el 2003
5 – 12 %
Panoramic
radiograph
Narhi etel 2000
1 mm
Models measurement
Roldan et el 2009
0.32 mm .
To develop a novel 3-dimensional technique to objectively measure the edentulous premaxilla change in bone volume.
2. To locate and quantify the change in bone volume of the premaxilla beneath complete denture opposing mandibular implant retained overdenture.
Objectives

2. The effect of mandibular implant overdenture on the volume of premaxillary bone beneath complete denture Mohamed Samih ALsrouji ¹ , Rohana Ahmad PhD candidate, University of Technology- MARA.
Methodology
11 patients were provided with maxillary complete dentures and mandibular 2-implant retained overdenture. CBCT were taken for the patients at two time points, P1 pre-treatment and P2 one-year post treatment. The images were converted using Mimics research software. 3-D models of the maxilla were calculated for pre and post treatment for each patient, then these models underwent superimposition. The premaxilla models were section in the same region and the bone volume changes quantified. Finally the 3-D models were exported to 3-matic software to reveal the predominant region and depth of bone resorption.
Pre-treatment model
1-yr post treatment model
Superimposition completed
Superimposition pre & post treatment models
Models sectioned with cutting plane
2 D outline of superimposed models
Superimposed premaxilla buccal view
Superimposed premaxilla palatal view
Pre-maxilla volume (pre)
Pre-maxilla volume (1 yr)
Extent (depth) of bone remodeling (mm)
Depth of premaxilla resorption and deposition in mm

3. The following chart shows the results of this study
The effect of mandibular implant overdenture on the volume of premaxillary bone beneath complete denture Mohamed Samih ALsrouji ¹ , Rohana Ahmad PhD candidate, University of Technology- MARA.
The following chart shows the results of this study
The range of premaxilla changes varied between % up to – 17.22% with an average of
– 8.65 % . This variation is due to anatomical, metabolic, functional, and prosthetic reasons (Atwood, 1971). The areas of bone changes can be identified clearly by utilizing 3- matic software.
Results
While some studies showed a minimum amount of bone resorption from 0 to 0.19 mm (Jacobs et el. 1993), other studies found higher resorption rate from 5 to 12 % (Kreisler et el. 2003) which is close to this study result 8.65 %. The main drawback of the previous studies was using 2 dimension radiographs which have an inferior accuracy than 3 dimension images, also the pervious techniques were not capable to present a precise map of bone change as in this study. The maximum bone resorption found in the buccal aspect of the premaxilla as well as at the top of the crest. The bone changes varied between -1 mm to +1 mm. The technique that used in this study will assist the researchers to compare the various treatment modalities of the edentulous mandible on subsequent bone remodeling in edentulous maxilla.
Discussion

4. Conclusion References
The effect of mandibular implant overdenture on the volume of premaxillary bone beneath complete denture Mohamed Samih ALsrouji ¹ , Rohana Ahmad PhD candidate, University of Technology- MARA.
Utilizing of this novel 3-D technique to quantify
the premaxilla bone remodeling provides
more accurate manner so it can be used
to compare different treatment modalities and
their subsequent influence on premaxilla remodeling.
Conclusion
1. Ahmad R, Abu-Hassan MI, and Swain MV (2013). Three dimensional quantification of mandibular bone remodeling using standard tessellation language registration based superimposition. Clinical Oral Implants Research 24:
2. Atwood DA (1962). Some clinical factors related to rate of resorption of residual ridges. Journal of Prosthetic Dentistry.
12:
3. Crum RJ, Rooney GE Jr. Alveolar bone loss in overdentures: a 5- years study. J Prosthet Dent 1978;40:610-3.
4. Jacobs R, van Steenberghe D, Nys M, Naert I. Maxillary bone resorption in patients with mandibular implant-supported overdentures or fixed prostheses. J Prosthet Dent. 1993;70:
5. Kelly E. Changes caused by a mandibular removable partial
denture opposing a maxillary complete denture. J Prosthet Dent. 1972;27:
6. Kreisler M, Behneke N, Behneke A, d´Hoedt B. Residual ridge resorption in the edentulous maxila in patients with implant-supported mandibular overdentures: an 8-years retrospective study. Int J Prosthodont. 2003;16:
7. Närhi TO, Geertman ME, Hevinga M, Abdo H, Kalk W. Changes in the edentulous maxilla in persons wearing implant-retained mandibular overdentures. J Prosthet Dent.
2000;84: 43-9.
8. Andrés López-Roldán 1, Diego Santolaya Abad 1, Isabel Gregori Bertomeu 1, Emma Gómez. Castillo 1, Eduardo Selva Otaolaurruchi. Bone resorption processes in patients wearing overdentures. A 6-years retrospective study. J Clin Exp Dent. 2009;1(1):e24-30.
References