Abstract
The present case report describes the dental rehabilitation of an atrophic maxilla in a 70-year-old female without a relevant medical record. The patient presented three-dimensional bone reabsorption of the upper alveolar ridge, altered intermaxillary relationship in the vertical, sagittal, and transverse planes. As well as, incisive papilla with vestibular position to alveolar ridge and loss of lip support. An overdenture retained by five implants was made with a macro geometry suitable for primary stability and a predictable biomechanical distribution according to the triangular shape of the maxillary arch. Combined with, surgical techniques of bilateral sinus lift and nasal floor lift. Additionally, a carbon-based implant retention system was used during the prosthetic phase. Prior to full treatment planning, the static and dynamic occlusion was stabilized with a complete upper denture and a removable partial lower denture. In the same manner, aesthetic and functional parameters were recovered along with the Vertical Dimension of Occlusion (VDO). Afterwards, the complete upper denture was used as a radiographic guide during the final treatment.
Highlights
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Our case report describes a prosthetic-surgical resolution for severely atrophic jaw case, when there are no options for traditional dental treatments.
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In our case, the available bone resource is maximized, using the naso-palatine canal as the surgical site, combined with bilateral sinus lift techniques, which provide a predictable option in cases of complex edentulous patients.
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Our therapeutic option not only contemplates surgical success, but also restores three-dimensional intermaxillary relations to the patient and an adequate lip support to perform a proper masticatory and speech function and quality of life for the patient.
Introduction
A severe atrophic jaw presents serious limitations for integral restoration to be conducted by conventional prosthetic techniques. This constitutes not only a prosthetic-surgical challenge, but| a functional and aesthetic challenge as well. Therefore, a predictable biochemical implant distribution for prosthetic planning is appropriate ( ).
There are several reported techniques including prosthetic rehabilitation using zygomatic implants. It is a non-bone graft dependent surgical procedure and minimizes the risk of failure in conventional implants ( ). None the less, this technique has invasive surgical risks, due to the presence of critical anatomical structures such as the ocular cavity ( ).
Implant retained overdentures are a viable alternative in severe atrophic jaw rehabilitations ( ). They provide aesthetic advantages such as masking between tissue union and prosthetic device in patients with either a wide smile, a high smile line or both. By the same token, they help to compensate for existing discrepancies in jaw ridges with complex morphology ( ). These are considered an adequate alternative when an implant failure occurs during a fixed rehabilitation and consequently, provide an inadequate anchorage ( ). There are several retention systems available for implant-retained overdentures. In addition to the choice of a retention system, the number of implants and their position, the patient’s hygiene, and prosthetic space are equally important ( ). Furthermore, due to the retained overdenture’s constant adjustment, maintenance and clinical follow up over time are required.
The selection of short implants presents a promising approach for patients with advanced atrophy. These were historically associated with lower survival rates and unpredictable long-term outcomes (Bahat, 2000). However, in view of their current improved design, scientific evidence suggests that short implants (>6 but ≤8 mm) have similar survival rates compared to standard implants (>8 mm) (Nisand & Renouard, 2014). Additionally, the minimum number of implants required for a maxillary implant-retained overdenture is four. (Steven & Nicola, 2016).
According to complementary surgical techniques for the atrophic maxilla, sinus floor elevation has become highly successful and predictable for bone augmentation when the height between the sinus floor and the alveolar ridge is insufficient for the placement of dental implants ( ). The nasal cavity is usually the height limit for placing implants in the premaxillary area, thus the increase of the nasal floor appears as a possible atrophic premaxillary area rehabilitation (Mazor et al, 2016).
An improvement in the indicators of satisfaction are observed in maxillary edentulous patients treated with implant-retained overdentures. That is to say, the present stability, retention, bite force, chewing efficiency, and oral health significantly improved compared to a complete upper denture ( ; Preciado et al., 2013).
This clinical case report describes the treatment of a maxillary edentulous patient with a five implant-retained overdenture (PR5) carried out by using Nasal and sinus lifts, along with Incisive canal implants and complementary less invasive surgical techniques.
Clinical report
The present case report describes the dental rehabilitation of an atrophic maxilla in a 70-year-old female without a relevant medical record. The patient presented three-dimensional bone reabsorption of the upper alveolar ridge ( Fig 1 A), altered intermaxillary relationship in the vertical, sagittal, and transverse planes. As well as, incisive papilla with vestibular position to alveolar ridge and loss of lip support and failures in the upper denture retention. The patient was edentulous in the upper jaw and according to the edentulism categorization, she had Kennedy class I in the lower arch. Furthermore, the intraoral clinical examination presented a small triangular shape in the upper jaw and severe bone resorption could be observed in the radiographic examination.
Bite blocks were defined according to aesthetic parameters including midline, labial line, canine lines, and occlusal plane. Lower facial height from Ricketts lateral cephalometric analysis was 47º, with a normal occlusal vertical dimension (OVD).
In the corrective phase, models were mounted in two stages: In the first place, the maxillary model was inserted with a facebow and secondly, it was mounted over a centric record to make a complete upper denture. Subsequently, a surgical guide was made to plan the implants surgery and a Three-dimensional stereolithographic model was requested to complement the treatment planning ( Fig. 1 B).
The surgical phase started with a supracrestal incision of a flap in the upper jaw and was later followed by a bilateral sinus elevation performed with the lateral window approach, as there was a sufficient residual bone height for a simultaneous placement of the implants( FIG 1 C. . Furthermore, natural bovine bone graft material was used and six L-PRF membranes were placed. Henceforth, two tapered implants, with a progressive and variable double thread design, were placed on both sides of the posterior upper jaw. The nasal floor elevation was performed and the nasopalatine canal was emptied.
Regarding the front upper jaw, two tapered implants (Ø 3.75-8mm) were placed on teeth 7 and 10 . And another one was positioned in the nasopalatine canal (NPC) since cortical bone density was available FIG 1 D. In addition to the aforementioned, a natural bovine bone grafting material, five L-PRF membranes, and a native collagen membrane obtained from porcine pericardium were used in the procedures.
Seven days after the implants were installed, a Cone Beam (CBTC) was performed ( FIG 1 E).
Then after seven months, in the implant abutments connection phase, the carbon-based implant retention system was connected. The system was composed by two bilateral posteriors angled at 15 degrees (Ø 3.8mm, GH 6.5mm) and another three, angled 0-degrees abutments (Ø 3.8mm, GH 6.5mm) in the anterior maxilla FIG 2 A.
