Important for implant primary implant stability, and influences immediate loading. Once secondary implant stability has been achieved (osseointegration), length is not as important. (Side note: thread pitch, drilling sequence, and bone quality also play a great role in gaining stability prior to osseointegration) [1].

Increases surface area of bone-implant interface.

Most stress of implant at first 5 mm making diameter important in stress reduction.

Larger diameter implants increase the surface area of bone-implant interface.

Disperses forces in poor bone, thereby reducing risk of overload.

Reduces the magnitude of force to system when used as part of bridgework or cantilever.

Increased diameter can allow for better emergence profile for larger crowns. In modern platform switch implants this is not the case, since the choice of prosthetic components is independent of the implant diameter.

Increased diameter of crest module size decreases the risk of implant fracture and prosthetic component fracture.

Concern for stress shielding from wide diameter implants leads to bone atrophy due to lack of strain transfer to the bone.

Increased diameter implants require a larger drilling, thereby reducing bone thickness around the implant. There is a current trend to not use wide body implants (>5 mm diameter) in order to preserve more alveolar bone.

Narrow (Reduced Diameter) implants are indicated in the anterior region of the maxilla or mandible. Narrow implants are more prone to implant fracture and internal connection damage, especially when placed in the posterior region. When placed in the posterior region, they shoud be splinted with other(s) implants. Modern alloys (TiZi) provide additional mechanical resistance to narrow implants, increasing survival rates.

Provides increased surface area.

Hydroxyapatite (HA) – HA-coated implants are no longer used as the processing methods convert HA to tricalcium phosphate which is rapidly absorbed and is easily colonized with bacteria. Additionally, there have been problems with delamination of HA.

Micro-rough surfaces 0.5–2.0 microns (minimally rough 0.5–1, intermediately rough 1.0–2.0, and rough 2.0–3.0 microns) create peaks and depressions in the implant to increase surface area. Roughened surfaces can be created by acid etching with such chemicals as sulfuric, hydrochloric, and hydrofluoric acids. Spraying the implant surfaces with titanium oxide, hydroxyapatite, and aluminum oxide is another option. Micro surface roughness causes an increased implant to bone surface area, clot retention, aids in earlier osseointegration, and leads to harder and stronger bone around implants by increasing mRNA expression of osteonectin and osteocalcin [2].

Electrowetting – wettability of implants important to improve plasma protein adherence and mesenchymal cell adherence and differentiation. Many methods are available, but commonly fluoride and magnesium ions are used. Some manufacturers package implants in saline.

Microthreads – preserves both bone and soft tissue around cervical portion of implant fixture by dissipating forces around crest. Can facilitate higher incidence of peri-implantitis due to plaque retention if the implant is exposed to the oral cavity.

Microgap – connection between implant and abutment.

Anti-rotational component – platform of the crest module has an anti-rotational feature to retain prosthetic component. This can be a platform such as an external hex (external connection) or within the implant body itself (e.g., internal hex, Morse taper, octagon, internal grooves, or pins).

External connection – connection to implant that is superior to coronal portion of implant creating a butt joint connection. Have higher prevalence of screw loosening, rotational misfit, and microbial penetration. Classic example is the External Hexagon connection.

Internal connection – internal connection to implant, seen in most modern implants. Can have parallel walls (Internal Hexagon) or morse cone type (connical connection). Conical connection preferred vs. flat connection as it can disperse load and prevent microgap elongation on function with fluid invasion. Connical connections have Improved microbial seal, reduced screw loosening, increased joint strength, and increased platform switching abutment options.

Platform switching – it is an horizontal offset between the implant connection and the cervical area of the abutment. This method can help to reduce crestal bone loss using a narrower restorative abutment compared to the crest module which leads to a more superior position of the epithelial attachment around the neck of the implant. This technique also medializes the implant abutment interface, which redirects stress from the crestal bone [3]. Inflammatory infiltrates are positioned away from the crestal bone leading to less bony destruction/loss [4, 5].

Titanium is a metal that presents low-weight, high-strength/weight ratio, low modulus of elasticity, excellent corrosion resistance, excellent biocompatibility, and easy shaping and finishing.

Most commonly used: Grade 4 pure titanium (cpTi), titanium-zirconium alloy, and titanium-6 aluminum-4 vanadium (Ti 6AL-4V).

Biocompatibility due to surface dioxide layer that forms almost instantaneously upon exposure to air (2–10 nm by 1 second). Important role in corrosion resistance, biocompatibility, and osseointegration. This oxide layer is composed of titanium dioxide (TiO₂).

Zirconia: Implants produced with zirconia are biocompatible, bioinert, radiopaque, and have a high resistance to corrosion flexion and fracture. They are typically considered “non-metallic” and are white in color.

Immobile when tested clinically.

No radiographic evidence of peri-implant radiolucency.

Vertical bone loss is less than 0.2 mm annually after the first year of service of implant.

Implant performance is characterized by an absence of persistent or irreversible signs and symptoms of pain, infection, neuropathy, paresthesia, violation of mandibular canal.

(These aforementioned success criteria were based on radiography, clinical signs, and symptoms. There are other factors today that we would take into account to establish implant success. New parameters to take into account include esthetics, soft tissue integrity/appearance, patient satisfaction, and prosthodontic parameters) [6].

• Distance of 1.5 mm between implants and natural teeth to allow for lateral biologic width. Violation leads to bone loss around implants and adjacent structures.

• Normal bone loss is <1.5 mm for the first year and 0.2 mm per year after (These numbers do not take into account the prosthetic construct used. For example, an implant supported FPD where forces are evenly distributed may have less bone loss per implant in the entire construct. Platform switching has also lessened the microbial bioburden that contributes to overall bone loss).

• A minimum distance of 3 mm between two implants must be adhered as to maintain interproximal bone height which provides room for restorative components.

• Minimum Distance of 1 mm of bone between implant and buccal/lingual wall. In the aesthetic zone, 2 mm posterior to buccal wall is desired for emergence profile and to preserve the buccal bone.

• Minimum Distance of implant apex is 1 mm from nasal floor.

   

Minimum Distance of implant apex is 2 mm above the inferior alveolar nerve.

Implant body 5 mm in front of mental foramen.

Head of bone level type implant should be 2–3 mm below gingival margin of planned crown to allow space for emergence profile.

Each 0.25 mm increase in diameter yields a 10% increase in surface area.

Classic integration timelines for smooth surface implants are 3 months for the mandible and 6 months for the maxillae. Modern implants surface treatments (SLA) can decrease time to as early as 6–8 weeks for conventional loading.

Ensure that drills are sharp and use new drills often, especially for dense bone.

Thermal necrosis during drilling occurs above temperatures of 47 °C. Keep RPM to 2000 or less and ensure pumping action during drilling to allow water to reach base of osteotomy.

Minimal intra-arch space of 5 mm for cement retained and 8 mm for screw retained for single crowns. More inter-arch space may be needed for overdentures or fixed hybrid prosthetics.

Minimal interarch clearance for a bar attachment is 12 mm.

Implants in a growing child will lead to a submerged implant, that is more palatal/lingual, out of occlusion and deep into alveolus, secondary to facial and dentoalveolar growth adjacent to the implant. Implants should be placed after confirmation of growth cessation by following growth indices for 1 year such as hand-wrist or spine radiography. Some authors recommend a minimum age of 15 for females and 18 for males. Literature shows reports of adult patients with continous alveolar growth, leading to vertical defects around the implant area.

Most implant drills have tapered tips of 0.5 mm beyond their established measurement.

In comparison to a medical grade CT, cone beam computed tomography (CBCT) uses about 2% of radiation dose.

40–60% of expected bone loss occurs during the first 36 months after the tooth is extracted.

Smoking – reduced success rate, about 6.5–20% lower than in nonsmokers [9].

Diabetes – need longer healing times to reach stability [10, 11].

Osteoporosis – studies have found similar rates of implant failure in patients suffering from osteoporosis vs patients with normal bone densities. Some weak evidence reduced bone healing and may consider longer healing times [12–14]. Higher risk for failure of bone grafting procedures in this patient population [15].

Oral bisphosphonates – AAOMS recommends a drug holiday of 2 months, for patients taking oral bisphosphonates, prior to surgery. The bisphosphonate should be held until osseous healing has occurred [16].

Avoid implants in patients using IV bisphosphonates or antiangiogenic drugs.

IV bisphosphonates or antiangiogenic drugs for cancer.

Denosumab – no studies to support discontinuation at this time [16].

Radiation of the head and neck: consider HBO if necessary (>60 Gy); failure rates similar with the advent of newer radiation protocols [17].

Parafunctional habit – consider wider diameter or stronger alloy implants. Judicious planning of designing load-sharing prosthetics, occlusal adjustments of prosthetics, and longer healing time for loading bearing bone formation may help counteract the destructive forces of parafunctional habits.

TMD complaints –assess for placement and length of procedure.

Debilitating disease – e.g., rheumatoid arthritis, scleroderma, or Parkinson’s disease that may cause xerostomia due to medications and make dental care difficult to maintain. Consider home assistance and prosthetic type, fixed vs. removable.

Head and neck exam as expected on all patients.

Lip support/gingival display on repose and animation. Short upper lip, high smile line, or hyperanimation may reveal artificial teeth and flange.

Width of remaining ridge. If edentulous a prosthesis with flange may be desirable vs. fixed crown and bridge to provide lip support and better esthetic outcome.

Papillae position and gingival margins of adjacent teeth.

Condition of the oral cavity and restorability of teeth to determine best prosthetic type.

Palpation of muscles of mastication and observe for hypertrophy of masseter, concern for parafunctional habit. Assess for wear pattern of teeth, bruxism, or occlusal interferences.

Occlusion – assess for angle classification, scissor bites, and cross bites and how these occlusions may affect implant success. May create prosthesis design issues or cantilevers. May require orthognathic procedures.

Inter-incisal opening ability to access site of implant.

Periodontal health/oral hygiene. Periodontal probings to ensure healthy cervical margins of adjacent teeth. Higher failure rate in those with poor periodontal status and poor hygiene (should be controlled before dental implant placement).

Gingival biotype: assess visibility of probe through gingival sulcus. Thick biotype associated with greater soft tissue stability, less recession, and is more resilient to oral flora.

Keratinized tissue – 2 mm or more of keratinized gingivae reduces gingival inflammation, increases implant survivability, and reduces marginal bone loss.

Interarch crown height space, ideal 8–12 mm for fixed restoration or 12 mm or more for bar connections.

Ridge contour – bone loss may push prosthesis palatal/lingual if restored with implant which will lead to extensive ridge overlap or food trap. Bone grafting may be indicated.

Articulated diagnostic models aid in planning with diagnostic wax-ups, stent fabrication, and easier measurements such as for prosthetic space.

Photos of patient in repose, full smile, lateral views for implants in the aesthetic zone.

Heals by creeping substitution – a process by which osteoclasts resorb bone creating new vascular channels with osteoblastic bone formation resulting in new haversian systems. Laying down new bone and subsequent resorption of old bone.

Osteogenic – transfer of osteocompetent cells for de novo bone formation, e.g., autografts.

Osteoinduction – bone formation by stimulation of host mesenchymal cells to differentiate, e.g., allograft, bone morphogenic protein.

Osteoconduction – providing scaffolding for new bone formation propagated by native bone. Does not contain proteins or cells, e.g., xenograft.

Osteogenic, osteoinductive, and osteoconductive.

Gold standard.

Disadvantage is a second surgical site.

Part of transforming growth factor β superfamily.

Recombinant DNA technology in Chinese ovarian hamster cells allows for transcription and collection of non-contaminated protein.

Water soluble, requiring a collagen type 1 carrier (acellular collagen sponge) for slow release. Requires 15 minutes of absorption.

Concentration of 1.5 mg/cc mixed with sterile water (do not substitute with normal saline as too hypertonic).

Chemotactic for preosteoblasts and stem cells as well induces expression of VEGF by osteoblasts.

Only on label use is currently for sinus augmentation or alveolar ridge reconstruction.

Will have extensive edema due to influx of fluid and cells from the chemotactic and neovascularization activities of BMP.

Allow healing of 6 months prior to implant placement.

Contraindications: (1) pregnancy, (2) allergy to rhBMP or type I bovine collagen, (3) active infection at recipient site, (4) active or history of malignancy at site, and (5) skeletal immaturity.

Postoperative steroids and icing of tissue may reduce the intensity of swelling.