The use of dental implants has been well documented as a successful treatment for complete or partial edentulism.
1
, 2
Initially, screw-retained prostheses were used for the restoration of completely edentulous patients.3
However, as implants were gradually used for the restoration of partially edentulous patients, new restorative concepts evolved, leading to cement-retained prostheses.4
, 5
Nowadays, both screw- and cement-retained restorations are used, each having its advantages and disadvantages. A drawback of cement-retained implant-supported restorations is the difficulty of retrievability,6
even if interim luting agents are used.7
, 8
, 9
Sometimes, a hole through the implant restoration is required to access the abutment screw. Several methods have been proposed for that purpose. Schwedhelm and Raigrodski10
suggested a ceramic stain on the occlusal surfaces of the restorations to identify the location of the screw-access chamber. However, this method gives only a 2-dimensional indication of the entry point. Other authors have suggested fabricating silicone putty indices and templates with or without guiding rods to indicate the direction of the screw access.11
, 12
, 13
, 14
However, these procedures involve additional laboratory time and cost, as well as the need of storage space for the casts and templates. Marking of the occlusal surface with a marker pen after determining the screw access point with the aid of a thickness gauge and the use of a digital photograph has also been suggested.15
This method also provides only a 2-dimensional indication.The present article presents a straightforward, inexpensive, and effective method for determining the entry point of the screw-access chamber. It has the advantage of showing the location of the fastening screw in relation to the implant-supported restoration in 3 dimensions. The method requires a digital single-lens reflex camera with a macro 90- to 105-mm lens, a photographic tripod, and a personal computer.
Procedure
- 1.Place the definitive cast with the implant abutments and the restorations close to the edge of a bench.
- 2.Mount the digital single-lens reflex camera with a 90- to 105-mm macro lens and a ring flash or side flashes on a photographic tripod. Adjust the height of the tripod. Align the camera directly over the definitive cast and focus on the restorations with a 1:1 magnification. Make the photograph (Fig. 1).
![Figure thumbnail gr1]()
Figure 1Metal-ceramic implant-supported restorations on definitive cast. - 3.Remove the restorations taking utmost care not to move the definitive cast. Photograph the implant abutments (Fig. 2).
![Figure thumbnail gr2]()
Figure 2Implant abutments on definitive cast after removal of restorations. - 4.Transfer the photographs to a computer (Mac Book Pro; Apple Inc). Create a new presentation using presentation software (Keynote v7.3.1; Apple Inc). Import the photograph of the definitive cast with the implant abutments. Then, import the photograph of the definitive cast with the implant-supported restorations. Choose the “Style” option of the software. Using the “Opacity” feature of the program, gradually decrease the opacity of the photograph of the restorations to the desired level (Fig. 3). The image of the abutments will show under the image of the restorations. If necessary, move the photograph slightly to achieve a perfect juxtaposition of the 2 photographs. The outline of neighboring crowns, natural teeth, or anatomic landmarks can be used for that purpose. Move to the presentation mode by clicking “Play.” Using the “shift”-“command”-“4” keys of the keyboard select and make a screenshot of the desired area. This will store the screenshot photograph as a portable network graphics (png) file on the desktop.
![Figure thumbnail gr3]()
- 5.The same result can be obtained by using photo editing software (Photoshop 19.0; Adobe Systems Inc). Use the following steps: Open the image of the implant abutments. This will be “Layer 1.” Open the image of the restorations by pressing CTRL+O. This will be “Layer 2.” Click on “Windows,” and then on “Layers.” Then click on “Layer 2,” which will be in the lower part of the “Layers menu” window. Click on the “down” arrow, which is next to “opacity.” A slider will appear. Click on and hold the slider arrow. Move the arrow to set the opacity to the desired level. The image of the abutments will show under the one with the restorations.
- 6.The same result can also be obtained with Windows Office Power Point 2016 (Microsoft Corp): Create a new presentation. Import the photograph of the definitive cast with the implant abutments. Then, import the photograph of the definitive cast with the implant-supported restorations. On the “Picture Tools Format” tab of the toolbar ribbon, select “Color.” Under “Recolor,” select “Washout.” This action will make the image of the definitive implant-supported restorations transparent, and the photograph of the abutments will show under one of the restorations.
- For the Photoshop (Adobe Systems Inc) and the Windows Office Power Point 2016 (Microsoft Corp) programs, the 2 overlapped images can be saved into the “Screenshots” folder by pressing the “Windows logo” and the “Prt Scr” keys simultaneously.
- 7.Store the png file in the patient's file in case screw loosening occurs. The photograph will help access the screw and remove the implant-supported restoration.
References
- Ten-year survival rates of fixed prostheses on four or six implants ad modum Brånemark in full edentulism.Clin Oral Implants Res. 1995; 6: 227-231
- Comparison of survival and complication rates of tooth-supported fixed dental prostheses (FDPs) and implant supported FDPs and single crowns (SCs).Clin Oral Implants Res. 2007; 18: 97-113
- A 15-year study of osseointegrated implants in the treatment of the edentulous jaw.Int J Oral Maxillofac Surg. 1981; 10: 387-416
- The “UCLA” abutment.Int J Oral Maxillofac Implants. 1988; 3: 183-189
- Alternative restorative techniques of the CeraOne single tooth abutment: a technical note.Int J Oral Maxillofac Implants. 1994; 9: 235-238
- Cement-retained versus screw-retained implant restorations: a critical review.Int J Oral Maxillofac Implants. 2003; 18: 719-728
- The effect of cementing agent and technique on the retention of a CeraOne gold cylinder. A pilot study.Implant Dent. 1995; 4: 32-35
- Use of luting agents with an implant system: part 1.J Prosthet Dent. 1992; 68: 737-741
- Cement failure loads of 4 provisional luting agents used for the cementation of implant-supported fixed partial dentures.Int J Oral Maxillofac Implants. 2000; 15: 545-549
- A technique for locating implant abutment screws of posterior cement-retained metal ceramic restorations with ceramic occlusal surfaces.J Prosthet Dent. 2006; 95: 165-167
- A simple, permanent index for abutment screw access for cemented implant-supported crowns.J Prosthet Dent. 2007; 97: 313-314
- Template to determine the position and angulation of the abutment screw channel for implant-supported, cement-retained restorations.J Prosthet Dent. 2012; 107: 134-136
- A modified technique to locate the abutment screw access opening of a cemented implant-supported restoration.J Prosthet Dent. 2012; 108: 58-59
- Simple device for locating the abutment screw position of a cement-retained implant restoration.J Prosthet Dent. 2013; 109: 272-274
- Occlusal-view photograph of a cement-retained implant prosthesis as a permanent guide for access-hole preparation.J Prosthet Dent. 2013; 109: 343-344
Article info
Publication history
Published online: June 28, 2018
Identification
Copyright
© 2018 by the Editorial Council for The Journal of Prosthetic Dentistry.
30367-6&id=gr1.jpg){kind=link}
30367-6&id=gr2.jpg){kind=link}
30367-6&id=gr3.jpg){kind=link}