​​​Stages of Bone Healing

1. Fibrinous exudate:
contained fibrin, polymorphonuclear
leukocytes and macrophages.
2.Granulation tissue:
Blood vessels, early fibroblasts,a range of thin collagen fibers.
3. Pretrabecular scaffold
dense, think, oriented collagen.
4. Woven bone.
5. Mixed woven and lamellar bone.
6. Bicortical bridge.

Screw Implant (S): Designed for medium and hard bone quality
After serial drilling, the bone is tapped and the implant screwed inside the prepared bone cavity.
If during drilling bone debris filled more than 2/3 of the flutes, the bone should be tapped 2 times, to remove any cortical stress during implant placement.

Cylinder Implant (C): Designed for poor bone quality
When the pilot drilled used and less than 1/3 of the flutes entrapped bone debris, do not continue with serial drilling.
Immediately insert the cylindrical implant and simultaneously compress the bone. The poor crushed cancellous bone trapped between the threads increasing the primary stability and promoting bone healing.

* = Cylinder Implant Only

• Immediately after the drilling the intra-bony temperature increases and the providing a stable dental implant inside the bone, osteocyted death extend between 100-500 um
• The early peri-implant trabecular bone formation and biologic fixation begins at 10-14 days after the surgery which differs from primary mechanical stability that is obtained during the implant placement
• Woven bone is progressively remodeled and substituted by lamellar bone. At three months, a mixed bone texture of woven and lamellar matrix can be found on the titanium implants
• Bone chips from the dental implant drill preparation or implant insertion envelope in a new formed peri-implant
• trabecular bone and seem to be involved in trabecular bone formation during the first weeks thus it is not recommended to wash the prepared cavity with saline prior implant placement
• The last stage of implant integration is the continuous, localized remodeling events to repair fatigue damage within interfacial and supporting bone (more than 12 months)

Bone-Implant Interface

• The newly formed network of bone trabeculae ensures the biological fixation of the implant and surrounds marrow spaces containing many mesenchymal cells and wide blood vessels. A thin layer of calcified and osteoid tissue is deposited by osteoblasts directly on the implant surface.
• Blood vessels and mesenchymal cells fill the spaces where no calcified tissue is present

Amorphous Layer 10-100nm

• Primary mechanical stability of a dental implant is a key factor of success. Regarding of one piece dental implant minimum of 30N/cm is needed.
• Excessive implant motion or poor implant stability results in tensile and shear motions, stimulating a fibrous membrane formation around the implant and causing displacement at the bone-implant interface, thus inhibiting osseointegration and leading to aseptic loosening and failure of the implant
• Primary stability depends on the surgical technique, implant design, implantation site.
• Cortical bone allows a higher mechanical anchorage to the implant than cancellous bone
• Mechanical stress and implant micro-motion are associated with implant osseointegration or failure.
• In a study, 20-30 microns of oscillating displacement was compatible with stable bone ingrowth with high interface stiffness, whereas 40 and 150 microns of motion were not compatible.

Appropriate space between implant and host bone may be useful for early peri-implant bone formation

• when bone is in tight contact with the implant surface, only poor bone formation or even bone resorptionobserved.
• Gaps exceeding 500 um reduce the quality of the newly formed bone and delay the rate of gap filling

J Dent Res. 2003 Mar;82(3):232-7.

• Two-piece implants were placed at the alveolar crest and abutments connected either at initial surgery (non-submerged) or three months later(submerged). Both groups of two-piece implants resulted in a peak of inflammatory cells approximately 0.50 mm coronal to the microgap and consisted primarily of neutrophilicpolymorphonuclear leukocytes. For one-piece implants, no such peak was observed.

Clin Oral Implants Res 7(1996),
Int J OralMaxillofac Implants 15(2000)

• As the most of the recession occurs during the first 3 months post-operatively, it was recommended of minimum of 3 months of surgery prior definitive impression
• Most of soft tissue recession have found during the first 6 months on the lingual sites which was more prodominent in women and in the mandible than maxillae
• supracrestal connective tissue lateral to the implant was found to be more richly vascularized in the flapless group than in the flap group
• Significant independent association also was found between the width of keratinized mucosa (less than 2mm) and radiographic bone loss in favor of wider zone of keratinized mucosa

Two piece/One piece Dental Implants

• Biologic Width dimensions of natural teeth are more similar to nonsubmerged implants compared to either two-piece nonsubmerged or two-piece submerged implants
• The tip of the gingival margin of one piece dental implant was located significantly more coronally (P<0.005) compared to two-piece implants

Clin Oral Implants Res. 2000 Feb;11(1):1-11

• The presence of microbes at the internal aspects of implant components
• Two piece-implant design may create a reservoir of bacteria and possibly facilitate the development of peri-implant inflammation
• Different implant-abutment connections, such as an internal cone, would yield a different distribution or intensity of inflammatory cell recruitment as compared withthe flat, butt-joint interface
• Microleakage is unavoidable among current implant systems, regardless of the connection type or interface size
• Restricted access of host defense mechanisms to the microgap, could perpetuate an acute inflammatory process

Quirynen etal , 1994; Jansen etal , 1992; Gross etal, 1999; Jansen etal ,1997;
Gross etal, 1999; Assuma etal, 1998; Grayes etal, 1998

Smokers 1 piece or 2 pieces dental implant

• One piece dental implant has higher success rate than 3 pieces dental implants in smokers and low hygiene patients.

Bone quality classification on the base of the surgeons hand’s sensation​​​​​​​

Primary stability

Primary stability immediately after dental implant and prior osseointegration is an important factor of dental implant success, it is more essential with one piece dental implant

Clin Oral Implants Res. 2001

Primary stability is determined by bone density, the surgical technique, and the microscopic and macroscopic design of the implant

Surgical techniques for improving the primary stability of implants

• Bicortical anchorage (apico-occlusal)/(buccal-lingual)
• Osteotome technique,
• Self-tapping implantation,
• Using a thinner drill than conventional methods for implantation

Immediate single-tooth implants, high insertion torque is a prerequisite for successful early loading procedures

• Martinez H, Davarpanah M, Missika P, Celletti R, Lazzara R. Optimal implant stabilization in low density bone. Clin Oral Implants Res. 2001;12:423–432.
• Olsson M, Friberg B, Nilson H, Kultje C. MkII–a modified self-tapping Branemark implant: 3-year results of a controlled prospective pilot study. Int J Oral Maxillofac Implants. 1995;10:15–21.
• Turkyilmaz I, Aksoy U, McGlumphy EA. Two alternative surgical techniques for enhancing primary implant stability in the posterior maxilla: a clinical study including bone density, insertion torque, and resonance frequency analysis data. Clin Implant Dent Relat Res. 2008;10:231–237.

Immediate load have been placed with high survival rate but low insertion torques

(Int J Oral Maxillofac Implants 2009)

• Extraction and immediate implant placement and provisionalization using a low-insertion-torque protocol of ≤25Ncm. Low rotational stability was not a contraindication to treatment unless there was a lack of axial stability. there maybe a misconception as to what actually represents adequate primary stability.

( Int J Oral Maxillofac Implants 2011)

• The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the strength of trabecular bone

Maxillae

The bone quality and implant stability is lower in the posterior area;
for this reason the posterior implant success rate is less than the anterior.
Clin Oral Implants Res. 1996

• But using our surgical methods, the success rate is not different

Bicortical Anchorage
Journal of Oral Rehabilitation, April 2009

But using our surgical methods, the success rate is not different buccal bi-cortical anchorages (0-0.5 mm)could significantly increase both bending and axial values of dental implants, but extra-buccal cortical bone engagement could not produce considerable incremental increases

• Increasing implant diameter could result in limited increases of values in case of implants being bi-cortically anchored.

Guided Bone Regeneration and one piece implant

• 2-3mm is needed between the edge of the membrane and extra-oral surface
• Having 2mm gingival height, permit to simultaneously one piece implant placement and the GBR

Anterior maxillae

One piece cylindrical implants compensate the angle between the root and the crown
if a screw implant was placed the tip of the abutment would be buccal
the implant can placed immediately after extraction