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Chapter 1

Basic Surgical Principles

This chapter presents the basic surgical principles related to the placement of Straumann implants in partially edentulous patients. To achieve successful osseointegration, a precise and low-trauma surgical technique is required. Surgeons must take important measures preoperatively to prevent postsurgical infection, handle surgical instruments expertly to preserve soft tissues, and carefully accomplish adequate implant site preparation without overheating the bone. Precise surgical protocol includes the following precautions:

• Preoperative mouthwash with 0.1% chlorhexidine

• Perioral skin disinfection with alcohol solution

• Antibiotic prophylaxis 2 hours prior to surgery (eg, 2 g amoxicillin intraorally)

• Low-speed drilling (between 500 and 600 rpm)

• Cooling spray during drilling with chilled sterile saline

• Intermittent drilling technique

• Use of sharp drills

It is important to perform a surgical procedure systematically, always applying the same surgical principles.

Fig 1-1 Smoothing the alveolar crest following flap elevation.

Fig 1-1a Once the implant surgical site has been exposed, a large round bur is used to smooth and level the crest of the alveolar ridge.

Fig 1-1b All sharp edges and irregularities are removed by running the round bur across the alveolar ridge.

Fig 1-1c In this cross section, the irregular, narrow crest is smoothed to produce a flat, wide ridge, which is favorable for implant site preparation.

Fig 1-2 Sequence of site preparation for a standard implant.

Fig 1-2a A no. 1 round bur is used to mark the position of the implant site.

Fig 1-2b Access is widened with a no. 2 round bur. This step makes it possible to correctly position the next drill.

Fig 1-2c The initial implant site preparation is made with a 2.2-mm-diameter pilot drill.

Fig 1-2d A 2.2-mm-diameter guide pin is inserted into the initial preparation to check its position and axis.

Fig 1-2e The crest of the osteotomy is enlarged with a no. 3 round bur.

Fig 1-2f A 2.8-mm-diameter spiral drill is easily inserted for preparing the depth of the site.

Fig 1-2g A profile drill is used to further increase the surgical access for the next, larger-size drill.

Fig 1-2h Preparation of the implant site continues with the 3.5-mm-diameter spiral drill.

Fig 1-2i Occasionally, when the bone structure is uniformly dense, bone tapping is performed prior to implant placement.

Fig 1-2j A standard implant is placed in the site, with the rough surface positioned at the level of the alveolar ridge crest. This allows the implant shoulder to be located at the gingival level.

Fig 1-3 Correction of the position and axis of the implant site preparation.

Fig 1-3a The preparation of the implant site begins with the use of the nos. 1 and 2 round burs to mark the position of the implant site.

Figs 1-3b and 1-3c Any required changes to the marking made with the first round bur can be accomplished with the no. 2 round bur, as shown in this occlusal view. These initial steps for the preparation of the implant site ensure the correct implant position orofacially and mesiodistally.

Fig 1-3d After the use of the first pilot drill (A), a 2.2-mm-diameter guide pin is used to check the axis and depth of the implant preparation (B). Any incorrect axis orientation can be adjusted with the same 2.2-mm-diameter pilot drill (C and D) and then followed with the 2.8-mm-diameter spiral drill (E).

Fig 1-4 Pretapping of implant sites with bone of varying density.

Fig 1-4a Tapping of the bone in the implant site is performed when the bone structure is uniformly dense (ie, type 1 bone). This is done through the entire depth of the implant bed.

Fig 1-4b If the alveolar ridge is partially dense (ie, type 2), tapping of the implant site to one third of the predetermined depth is done within the crestal area.

Fig 1-4c When the alveolar ridge is predominantly cancellous bone (ie, types 3 and 4), no tapping of the bone is required prior to implant placement.

Fig 1-5 Varying sink depths.

Fig 1-5a The 3.5-mm-diameter depth gauge is inserted so that the middle of the 12-mm mark is aligned with the bone crest (left). When the standard implant is inserted, this allows the rough border to be aligned exactly at the crest (right).

Fig 1-5b If the implant site is prepared with the 12-mm mark slightly below the crest, the rough border of the inserted implant will be positioned approximately 0.5 mm below the crest. This approach is most often used in posterior implant sites for a nonsubmerged implant healing.

Fig 1-5c The implant site is prepared to the 14-mm mark, and the profile drill is used to flare the coronal portion of the crest. A 12-mm-long standard implant can be inserted more deeply to partially submerge the machined collar. This approach is normally used in esthetic implant sites for a submerged implant healing.

Fig 1-6 Overview of implant site preparation and implant placement.

Fig 1-6a The implant site is prepared to a diameter of 2.8 mm to receive a narrow neck or a reduced-diameter implant. Pretapping, as shown in Fig 1-4, is rarely used with these implants.

Fig 1-6b When a standard implant is used, the implant site is prepared to a diameter of 3.5 mm. Pretapping, as shown in Fig 1-4, is rarely used.

Fig 1-6c The implant site is prepared to a diameter of 4.2 mm, and a wide body or wide neck implant is inserted. Pretapping, as shown in Fig 1-4, is used more often due to larger implant diameter.

Fig 1-7 Selection of implant length in the posterior mandible.

Fig 1-7a In regions restricted by anatomic limitations, shorter implants are frequently used. In this long-span mandibular distal extension situation, two implants are placed to support a three-unit fixed partial denture. An 8-mm short implant (right) is used to avoid the mandibular canal.

Fig 1-7b In a short-span mandibular distal extension situation, two short implants with lengths of 6 and/or 8 mm may be indicated. They are used here to avoid the mandibular canal. These short implants are often restored with splinted crowns.

Fig 1-8 Selection of implant length in the posterior maxilla.

Fig 1-8 In the maxillary posterior distal extension situation, the maxillary sinus can be avoided with the use of shorter implants. Here, two implants (12 and 8 mm) are inserted in the second premolar and first molar sites, respectively, in close proximity to the sinus.

Fig 1-9 Minimum width of alveolar crest for implants of varying diameter.

Fig 1-9a In the premolar site, a crest width of at least 6 mm is recommended for a standard implant.

Fig 1-9b In the molar site, a wide body or wide neck implant requires a minimum crest width of 7 mm.

Fig 1-9c In the anterior region, where a narrow neck implant is often indicated for the replacement of lateral incisors, a minimum alveolar crest width of 5 mm is required.

Fig 1-10 Minimum space of single-tooth gaps for various implant types.

Figs 1-10a and 1-10b Occlusal (a) and lateral (b) views of regular neck implants. A space of at least 7 mm is required for the 4.8-mm-diameter implant shoulder shown here.

Figs 1-10c and 1-10d Occlusal (c) and lateral (d) views of wide neck implants. The 6.5-mm-diameter implant shoulder requires a single-tooth gap of at least 9 mm.

Figs 1-10e and 1-10f Occlusal (e) and lateral (f) views of narrow neck implants. In sites that require narrow neck implants, a minimum of 5.5 mm is needed to accommodate the 3.5-mm-diameter implant shoulder.

Figs 1-10g A minimum interocclusal distance of 5.5 mm from the implant shoulder to the opposing dentition is necessary to allow the placement of the abutment and crown.

Fig 1-11 Spacing between implants or between implants and teeth.

Figs 1-11a and 1-11b Occlusal (a) and lateral (b) views of a regular neck implant placed next to a tooth. A distance of approximately 4 to 5 mm is required between the central axis of the implant and the root surface of the tooth at the alveolar crest.

Figs 1-11c and 1-11d Occlusal (c) and lateral (d) views of a wide neck implant placed next to a second premolar. The wide neck implant is positioned approximately 5 to 6 mm from the tooth.

Figs 1-11e and 1-11f Occlusal (e) and lateral (f) views of regular neck implants. When two regular neck implants are placed side by side in a posterior distal extension situation, the first implant should be positioned 4 to 5 mm from the tooth and the second implant should be positioned 7 to 8 mm from the anterior implant.

Figs 1-11g and 1-11h Occlusal (g) and lateral (h) views of regular neck and wide neck implants. When a regular neck implant and a wide neck implant are indicated to replace a missing second premolar and molar, the regular neck implant should be placed 4 to 5 mm from the tooth and the wide neck implant placed approximately 9 mm from the anterior implant.

Figs 1-11i and 1-11j Occlusal (i) and lateral (j) views of implants positioned in the first premolar and first molar sites. In this extended posterior distal extension situation, a regular neck implant and a wide neck implant are indicated as abutments for a three-unit fixed partial denture. The regular neck implant is positioned 4 to 5 mm from the tooth. The wide neck implant is inserted about 16 mm from the anterior implant.

Figs 1-11k and 1-11l Occlusal (k) and lateral (l) views of a short distal extension situation. A regular neck implant is indicated to restore the missing first molar and serve as a distal abutment to a combined tooth- and implant-supported three-unit fixed partial denture. The implant is positioned 11 to 12 mm from the tooth.