|Year : 2015 | Volume
| Issue : 1 | Page : 48-52
Overview of surgical guides for implant therapy
T Umapathy1, Chirenjeevi Jayam2, BS Anila3, CP Ashwini4
1 Department of Pedodontics and Preventive Dentistry, Rajarajeswari Dental College and Hospital, Bengaluru, India
2 Department of Pedodontics and Preventive Dentistry, Himachal Pradesh Government Dental College, Shimla, Himachal Pradesh, India
3 Department of Conservative Dentistry and Endodontics, Himachal Dental College, Sundernagar, India
4 Dental Surgeon, S.B. Patil Dental College and Hospital, Bidar, Karnataka, India
|Date of Web Publication||2-Apr-2015|
Department of Pedodontics and Preventive Dentistry, Rajarajeswari Dental College and Hospital, No. 14, Ramohalli Cross, Kumbalgudu, Mysore Road, Bengaluru - 560 074, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Prosthetically driven implant prosthesis assures good aesthetics, function and more importantly hygiene maintenance enabling long time success. Accuracy in treatment planning and implementation of planned treatment is vital for this success. Following advancements that have occurred in treatment planning (virtual software) for implant prosthesis; an equal rise is to be expected in transferring the planned therapy to surgical fruition. In this regard, surgical templates have enabled clinician to deliver predictable surgical & prosthetic rehabilitation. Surgical guides have not only decreased the chances of iatrogenic damage of critical anatomic structures; they also increase the esthetic and functional advantages of prosthodontic-driven implant. Within the constraints of this article, the authors describes an over view of use of surgical guides in clinical situation. If clinician is considered a pilot, then surgical guide is his navigator.
Keywords: CAD-CAM prosthesis, guided surgery, implants, planned guides, surgical guides
|How to cite this article:|
Umapathy T, Jayam C, Anila B S, Ashwini C P. Overview of surgical guides for implant therapy. J Dent Implant 2015;5:48-52
| Introduction|| |
The use of medical imaging and software planning has led to considerable improvement in treatment planning.  Surgical guides now play an important role in transferring this premapped plan to placing the implants at their designated positions (angulation and depth).  There are several explanations why one should use a surgical guide for successful implant placement. Use of the surgical guide is just not limited to placing implants in critical anatomical situations but also for placing implants routinely at ideal positions in the bone increasing the esthetic and functional advantages of prosthodontic-driven implant.  Manual errors of placement can be prevented. 
Glossary of prosthodontic terms-8 defines surgical template as a guide used to assist in proper surgical placement and angulation of dental implants.  Surgical guide is the link between what's in mind (treatment planned) and what will be executed (treatment). Predetermining the appropriate osteotomy path for the clinician significantly helps the surgical procedure. If the clinician is considered a pilot, then surgical guide is his navigator.
| Uses of surgical guide|| |
- Guidance of osteotomy drills at correct position, angulation and depth
- Guidance of implant fixtures at correct position, angulation and depth
- Guidance of amount of bone reduction or bone harvesting if necessary (both soft tissue and hard tissue harvesting). ,,
Surgical guides feature several advantages
- Decreases manual errors associated with free hand implant placement
- Minimally invasive procedure-since surgical guides allow minimal intervention, postoperative surgical problems are minimized providing psychological benefit to both patient and clinician
- Precision - Implants are prosthetically driven components; any deviation can lead to abrupt results in functioning. With surgical guides, implant placement has become more accurate
- Safety - Safety is the biggest factor when placing implants in critical areas of the mouth. Even the slightest error can lead to severe complications. With guides, such deviations can be prevented. Vital structure damage is easily prevented
- Predictability - Alertness throughout the whole procedure cannot be maintained. Even experienced hands are associated with decreased quality in comparison to guided implantation technique
- Aesthetics - It is seen that use of surgical guides to transfer software planning to the actual placement has shown good cosmetic results
- Hygiene - Maintenance of proper oral health is ensured because of correct implant placement
- For best survival, implant supported prosthesis should be placed in preplanned positions. Guides can help such quality placements of implants
- Reduction of implant surgery time
- Ease in fabrication: Most implants have built-in software, which enables online shopping and ordering with a single button
- Special surgical guide types, such as bone reduction guides are available that can enable graft harvesting
- Guide itself can act as a temporary prosthesis for fully edentulous cases
- Increased visibility of the surgical site and easy access for flap exposure
- Accurate results for beginners
- Foresee the costs
- Reduce own costs because less implant surgery time is necessary and the absence of failures. ,,,,
- Once if guides are fabricated, they do not allow any change or modification from predetermined position if required at the time of surgery
- Any tissue changes (e.g. Swelling, loss of abutment teeth) between time of ordering and implant installation can alter fit of the prosthesis ultimately functioning of implant prosthesis
- Guide dislocation can occur during surgery if the guide is not stabilized
- Drill lodgement in stents
- Guide dislocation also occurs when drilling is intended to penetrate hard bone, producing torsional forces on the sleeves, thus lifting off the guide
- Start-up cost associated with software purchasing
- Greater learning curves. ,,,
Classification of surgical guides
Based on the area of operation
Guides for partially edentulous sites (tooth supported or bone supported-depending on amount of the edentulous space) and Guides for completely edentulous sites (mucosa or bone supported).
Based on the support the surgical guides derive
Tooth supported, Bone supported, and Mucosa supported. Rules for planning usage of different types of surgical guides: 
- Tooth supported guides - Minimum three stable teeth should be present to support the guide during surgery [Figure 1]
- Mucosa supported guides - It is used in fully edentulous sites. Advantage-less or no tissue reflection is required, so less postoperative discomfort. Will require scan prosthesis and surgical guides during surgery [Figure 2]
- Bone supported guides - They are used in partially edentulous sites and completely edentulous sites. When used in partially edentulous sites, it should possess at least 3 cm of supporting bone or 3 teeth would need replacement. Bone guides are especially used when edentulous sites possess thin bone. Raised flap should provide a good view to implant sites and insertion of guides [Figure 3].
Based on the accessibility
Surgical guides can be open sleeve or closed sleeve (increased accessibility). 
Base on utility
- Pilot guides - The sleeves only allow pilot drills. Angulation control is achieved. Depth control is to be obtained manually by assessing markings on drills. Later, the surgical guide is removed, and osteotomy site is expanded in the absence of surgical guide
- Complete drill guides - It uses drill keys or sleeves. Different sleeves for different diameters of drills, which are changed concomitantly as osteotomy is widened. Angulation as well size of osteotomy is controlled by guide; depth is controlled manually
- Safe guides/easy guides - Uses drill key or sleeves as above with additional implant stopper that controls the depth of drilling. Allows both osteotomy preparations with surgical drills and installation of implants. ,
Based on material
Self/light cure acrylic resin, metal reinforced acrylic templates; vacuum formed polymers, milling, CAD-CAM prosthesis, stereo lithographic models. The surgical accuracy of manually processed resin and vacuum formed guides is less in comparison to the latter mentioned milling, CAD-CAM prosthesis or stereo lithographic models. ,,
Guided surgery kit
A standard guided surgical kit contains mucosal punch, drill handle, c handle, template fixation pins, retentive anchor driver, stop key for guided implants, T-sleeve, guide tubes.
Selection of retentive anchor pins
Different types of surgical guides require diverse considerations for stabilizing the guide. Important rule is - " If guide itself is not stable, then the whole implant procedure goes haywire." Considerations should be decided regarding type of the surgical guide, implant number, position of edentulous site, presence of any anatomical limitations (maxillary sinus, mandibular nerve), and length of fixation screws.
Ideally the fixation screws should be positioned vertically because vertical position stabilizes the guide the most and also the have the added advantage of easier accessibility for placement.
Considerations for deciding retentive anchors for tooth supported guides
If edentulous site is bound by teeth bilaterally, then fixation anchor is positioned in the middle of the edentulous site. If distal edentulous site: Fixation anchors are positioned as distally as possible in the arch, not necessarily adjacent to distal edentulous site.
Considerations for deciding retentive anchors for mucosa supported guides
At least three in number. Two anchors positioned at distal ends, and one anchor positioned in the center of edentulous arch. The distal areas or posterior areas usually contain important structures such as maxillary sinus, mandibular nerves. In such conditions, we have to take these structures into consideration and plan more distally as possible. While using a mucosa supported guides, the undercuts are relieved in the labial region where the fixation anchors are attached. Screwing in these areas can lift the guide away from the mucosal tissues. Latter can be prevented by holding the guide initially till at least positioning one screw in position [Figure 4].
Considerations for deciding retentive anchors for bone supported guides
Two fixation anchors are enough to rigidly fix the guide to the bone. One on the right side and other to the left. In the undercut area, tilting off or lift off of the guide can occur on tightening the screw. Latter is prevented by holding the guide while the second anchor is tightened. It is not a rule that the whole of the guide should contact bony tissue. 
Flow chart for surgical guide use
Step 1: Diagnosis and treatment planning.
Step 2: Virtual implant and prosthesis planning with software.
Step 3: Selection of particular implant system and components.
Step 4: Planning for the surgical guide compatible with particular implant system.
Step 4a: If more than 3 teeth-tooth borne, if less than 3 teeth-mucosa or bone borne surgical guide.
Step 4b: Selection of anchors (depending on the site, implant number, angulation, anatomical limitation)
Step 5: Surgical guide fabrication (online ordering is possible with most soft wares)
Step 6: Disinfection of received surgical guides followed by evaluation of guides.
Step 6a: For teeth supported-evaluate on cast and patients mouth.
Step 6b: For mucosa supported-evaluate on cast and patients mouth, for a mucosa-supported guide, it is recommended to make a surgical index to stabilize the guide during fixation.
Step 6c: For bone supported-evaluate on digital bone model.
Step 7: Verification of specific surgical drills and drill keys.
Step 8: Stabilization of guides in patient's mouth using anchor pins followed by verification of the guide stability.
Step 9: Drill sequence.
Step 10: Fixture installation (possible with safe guides).
| Discussion|| |
Digital technology has proved an invaluable tool in the way we diagnose the condition and plan the treatment. However, even the bestest of plans seems worthless if not properly executed.  Anatomical limitation and better prosthetics demands the surgeon to gain more precision in surgical positioning of dental implants. , During oral implant placement, the drill (position, depth and angulation) must be guided by the surgeon according to the final form of the prosthetics. Ideal placement facilitates the establishment of favorable forces on the implants and the prosthetic component. In this regard, surgical guides have shown better predictability of placement improving better prosthetic results. , Several guides have been reported in the literature such as self/light cure acrylic resin, metal reinforced acrylic templates, vacuum formed polymers, milling, CAD-CAM prosthesis, stereo lithographic models. , Out of these; Milling, CAD-CAM prosthesis or stereo lithographic models have provided good results. , Care should be taken care in deciding type of surgical guide and method of fabrication, selection of anchors (depending on site, implant number, angulation, and anatomical limitation). 
| Conclusions|| |
- Transferring of computed tomography plan information to surgical field remains a critical point in implantology, and surgical guide is proving its worth
- Surgical guides enables clinician in establishing good implant prosthetics, providing excellent esthetic, function, and hygiene maintenance.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]