|Year : 2016 | Volume
| Issue : 2 | Page : 75-78
Two narrow implants replacing a mandibular right first molar: A case study
Zankhana Shah1, Amar Shah2, Priyanka Raiyani3
1 Department of Prosthetics and Implantologist, Private Practice, Ahmedabad, India
2 Department of Orthodontics, Private Practice, Ahmedabad, India
3 Department of Oral and Maxillofacial Pathology, GDCH, Ahmedabad, India
|Date of Web Publication||15-Mar-2017|
401, Surbhi Apartment, Off Red Bungalow, CG Road, Ahmedabad - 380 006, Gujarat
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The most frequent single molar to be replaced is the first mandibular molar because this tooth is lost first. Implantation in the posterior area is a predictable procedure over time. The low rate of complications in addition to the high long.term success rate makes implant restoration a reliable solution to treat posterior partial edentulism. The use of two implants to replace a single molar seems a logical treatment solution. The following case deals with the replacement of the lower right first molar having a previously failed root canal treatment with two narrow implants of diameter 3.5. mm and height 10. mm. Replacing a single missing molar with two narrow dental implants serves as a viable treatment option providing good and predictable long.term results.
Keywords: Dental implants, diameter, narrow implants
|How to cite this article:|
Shah Z, Shah A, Raiyani P. Two narrow implants replacing a mandibular right first molar: A case study. J Dent Implant 2016;6:75-8
Dental implants are replacement tooth roots. Implants provide a strong foundation for fixed or removable replacement teeth that are made to match the natural teeth. Planning of an implant treatment starts before the extraction. The timing of the implant placement , is the fourth dimension in the treatment planning for an implant. In the following case report, we have discussed the replacement of the lower right first molar having a previously failed root canal treatment with two narrow implants of diameter 3.5 mm and height 10 mm.
| Materials and Methods|| |
A 52-year-old patient complained of pain in the lower right back region. Radiographically, it showed a failed root canal treatment in the lower right first molar region. There was a pain on percussion along with radiolucency in the mesial root of the right first lower molar. On removal of the crown, it was noted that minimal coronal tooth structure was present, and radiographically, it was confirmed that the tooth had a poor prognosis from a restorative aspect.
The tooth was hence extracted, and the site was bone grafted with perio glass.
The patient was recalled 4 months after the extraction. Following a thorough medical history to rule out any systemic contraindication, the clinical and radiographical evaluation was performed during the visit. The bone height, width, and density were assessed with the help of a cone beam computed tomography scan. All bone parameters were improved and maintained. However, the bone was a little immature. He was informed of all the viable treatment options in relation to the missing lower right first molar, and the detailed risks and benefits of the proposed treatment followed by a written consent-to-treat agreement and the site was finally planned for the placement of two narrow implants sized 3.5 mm × 10 mm [Figure 1] and [Figure 2].
|Figure 1: Radiograph showing a failed root canal treatment in the lower right first molar along with cone beam computed tomography sections showing bone densities in Hounsfield unit|
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|Figure 2: Radiograph showing the extraction space along with cone beam computed tomography sections showing bone densities in Hounsfield unit|
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One versus two implants
A 6 mm diameter implant in a 12 mm or more mesiodistal space has a 3 mm of cantilever. Such a large cantilever increases shear stress to the prosthesis, implant, and bone. Predictably this leads to higher rates of porcelain fracture, screw loosening, implant fracture, and bone loss [Figure 3].
|Figure 3: Orthopantomograph showing an implant of 6 mm in the space of 12 mm measured mesiodistally|
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To minimize the risk, disk the contacts to get 1.5 + 3.5 + 3.0 + 3.5 + 1.5 mm of spacing. Here, 3.5 mm represents the diameter of the implants and 3.0 mm the distance between the two implants [Figure 4].
|Figure 4: Orthopantomograph showing two narrow implants of diameter 3.5 mm with a spacing of 3 mm, placed in the space of 12 mm mesiodistally, hence minimizing the cantilever|
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The operating field was sterilized. The patient was made to rinse with 10 ml of 0.2% of chlorhexidine gluconate solution followed by extraoral scrubbing with 5% povidone iodine. Under local anesthesia, an incision was placed over the site, and the mucoperiosteal flaps were reflected to expose the bone. A pilot drill was introduced into the bone, and two osteotomy sites were created. First on the mesial lingual and the second on the distobuccal side.
They were taken to the desired depth. The sites were progressively enlarged and finished with the dedicated osteotomy drill. The profile gauge was inserted, and depth checked to ensure that the implant would sit just subcrestal. The dedicated tap was then introduced into the site to the depth established.
Two mini implants of size 3.5 mm × 10 mm were carefully threaded into the prepared sites with 25N and a healing cap was placed on each. The flaps were closed with 3-0 silk sutures [Figure 5].
|Figure 5: (a) Top view of the healing cap. (b) Guide for the placement of healing screws. (c-e) Different angles showing healing caps|
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The patient was recalled for the next treatment phase. The healing caps were removed. Indirect open tray impression was taken. Zig trail was taken to check the impression perfection which was confirmed by a radiograph.
Metal trial along with final bite was taken in the next visit after which patient was recalled for a Bisque trial for recording the occlusion. This was followed by the final placement of the prosthesis. The occlusal approach is open as it is screw retained and was closed by composite restoration [Figure 6] and [Figure 7].
|Figure 7: (a) Filed root canal treatment, (b) implant site after extraction, (c) implants with healing caps, (d) metal trial, (e) final prosthesis|
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| Discussion|| |
Dental implants do not require reducing other teeth, as a tooth-supported bridge does. Because nearby teeth are not altered to support the implant, more of our own teeth are left intact, improving long-term oral health. Individual implants also allow easier access between teeth, improving oral hygiene.
Poor bone quality in the posterior regions,, especially the maxilla, could jeopardize the short- and long-term implant success. Anatomical considerations and adjacent vital structures (i.e. maxillary sinus and mandibular canal), occlusal loads, and the occlusal table, which is frequently wider than the implant diameter, should also be of some concern. Quality and density of the bone in the posterior regions can compromise initial implant stabilization and load transfer to the bone. The most frequent single molar to be replaced is the first mandibular molar because this tooth is lost first., Implantation in the posterior area is a predictable procedure over time. The low rate of complications in addition to the high long-term success rate makes implant restoration a reliable solution to treat posterior partial edentulism.
Studies on bite force  measurement indicate that there is a considerably greater force generated in the posterior compared with the anterior part of the same jaw., Occlusal forces can be 3–4 times as great in the molar region compared with the incisor region. The quantity of available bone for implant placement , in the posterior is limited by the lingual concavity and the inferior alveolar nerve in the mandible, and by the sinuses in the maxilla. There is also generally an inferior quality of bone in the posterior region compared with the anterior region of the same arch. These conditions create a need for carefully selected treatment plans for posterior single-tooth replacement using osseointegrated dental implants.
Relatively, the success rate of two implants is higher than one, and hence the use of two implants to replace a single molar seems a logical treatment solution to avoid prosthetic complications.
Implant placement: A brief discussion on one versus two implants
Single regular-diameter implants might be incapable of predictably withstanding molar masticatory function and occlusal loading forces. Wide-diameter implants are a suitable alternative for replacing a missing molar in some cases; however, the use of two implants has been successfully demonstrated to be a functional and more biomechanically sound method of molar replacement. Wide-diameter implants , are not always a treatment option for replacing a single molar, especially when the buccolingual dimension is deficient. The use of two implants might also provide better prosthetic stability and prevent rotational forces on the prosthetic components [Figure 8].
Restoration of missing molars with one wide-diameter implant has a greater incidence of screw loosening  and compared with two implants, has a greater incidence of prosthesis mobility and a higher failure rate. When narrow implants are used as single tooth replacement,, especially in the molar region, an increased risk of screw  loosening or fracture  exists due to the combination of high masticatory forces, buccal-lingual mandibular movement, and cusp-groove orientation. Therefore, the use of two implants to replace a single molar is a logical treatment solution to avoid prosthodontic complications.
One significant barrier to the widespread use of this concept is the limitation of the size of implants and their associated prosthetic components. Nevertheless, when using narrow implants, two implants could be used even when the distance between the adjacent teeth is rather limited.
This case study provided evidence for the usefulness of two narrow diameter implants to replace a single molar.
| Conclusion|| |
Replacing a single missing molar with two narrow dental implants serves as a viable treatment option providing good and predictable long-term results.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
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