Initial situation

A systemically healthy 66-year-old female patient came to the clinic with the chief complaint of instability of her upper complete removable prosthesis. She was seeking a fixed solution to allow her to eat and chew properly. Her dental history included the extraction of the upper teeth more than six months ago. In the extraoral examination, the face was symmetrical and oval. The smile was harmonious, and the lips were classified as thin (Figs. 1-3).

The intraoral examination revealed multiple missing teeth and bilaterally abfraction in the lower premolars and tooth #36. In addition, the patient presented poor oral hygiene and dental calculus in the anterior lower jaw and upper prosthesis (Figs. 4-11).

The radiographic examination showed radiopaque findings compatible with a root canal treatment on tooth #45 and restorations on teeth #35, #34, and #45. Furthermore, approximately 50–75% alveolar bone loss was observed in the lower jaw (Fig. 12).

Treatment planning

Considering the patient’s needs and expectations, and after a detailed clinical and radiographic assessment, a removable full-arch rehabilitation supported by six Straumann® Mini Implants was planned in the upper jaw.

The initial phase consisted of mechanical plaque removal, oral hygiene instructions and the extraction of hopeless teeth. The rehabilitation in the lower jaw was scheduled for a second phase of the treatment.

The rationale for the use of Straumann® Mini Implants (Ø 2.4 mm) was the limited horizontal bone availability, the patient’s financial situation, and her desire for an efficient solution and reduced morbidity. These mini implants present a one-piece design with the Optiloc® retentive system characterized by high wear resistance, resulting in low maintenance and increased patient comfort.

The duplication of the patient’s prosthesis was used as a reference for implant placement.

Surgical procedure

Following the intraoral (chlorhexidine 0.12%) and extraoral (chlorhexidine 2%) antisepsis, infiltrative vestibular (articaine 4% with epinephrine 1:100,000), and palatal (2% lidocaine with epinephrine 1:100,000) anesthesia was carried out.

Mucoperiosteal flaps were raised through a crestal incision along the maxillary ridge. The bone anatomy situation was assessed, and no edge regulation was required. The drilling protocol was performed following the manufacturer’s instructions, using the Ø 1.6 mm needle drill. Since the anterior area presented bone quality type III, only one drill was required for the implant bed preparation.

Four mini implants (Straumann® Mini Implant Ø 2.4 mm - SLA® - 10 mm, Optiloc® - Roxolid®) were placed in positions #14, #12, #22 and #24, and two mini implants (Straumann® Mini Implant Ø 2.4 mm - SLA® - 12 mm, Optiloc® - Roxolid®) in positions #16 and #26. The implants were inserted manually with the aid of a contra-angle handpiece. A torque of 30N was applied to the four anterior implants, compared to 15N to the two posterior ones. The flaps were sutured with 5-0 nylon (Figs. 13-18).

A panoramic X-ray was taken, and no complications were observed. The patient received oral and written instructions about medication, oral hygiene, and diet. The prescription included Clavulin® BD (amoxicillin 875 mg and clavulanic acid 125 mg), nimesulide 100 mg, dexamethasone 4 mg, and promethazine 500 mg. In addition, she was instructed to rinse with chlorhexidine digluconate 0.12% twice a day for ten days (Fig. 19).

Prosthetic procedure

The old prosthesis was modified to create space for the implants to transform the denture into an implant-supported prosthesis.

To this end, the first step was to place the white processing collars on each Optiloc® to block out the surrounding area. Next, a matrix housing with a retention insert was placed on each Optiloc® abutment, leaving the collar beneath it (Figs. 20,22).

Next, the existing denture base was adapted in the areas of the Optiloc® using a resin bur, and a minimum margin of 1 mm around the housings was left to allow for sufficient thickness of the resin.

The denture was seated using silicone, and adequate clearance between the matrix housings and the denture base was achieved by adjusting the prosthesis base until a passive fit was obtained (Figs. 23,24).

Next, the denture was prepared before the application of self-curing PMMA resin in the matrix housings of the denture and then placed in the patient. Once the denture was set, the patient was maintained in centric occlusion until the material was cured. Afterward, the denture was removed with the collars, which were then discarded, and all excess material was removed (Figs. 25-29).

For the final restoration, the Optiloc® impression copings were placed, and an impression was taken in a centric position. In the dental lab, the Optiloc® analogs were inserted into the impression copings. The master model was prepared, and the matrix housings and processing collars were positioned with the aid of the Optiloc® Retention Insert Instrument (Figs. 30-35).

Afterward, a new prosthesis was prepared; and esthetic and functional evaluations were performed on the patient during this process (Figs. 36-39).

Treatment outcomes

Mini implant treatment becomes viable for the profile of patients who need excellent overdenture stability with a less invasive procedure. Furthermore, the patient was delighted with the treatment outcome as her quality of life had increased since she could chew again without any unstable overdenture and thanks to the low morbidity during the treatment (Figs. 40,41).