Sinus lift, bone graft and dental implant (Proceedings of the scientific research, Ho Chi Minh City Dental Hospital, p.41-49)
Prof. Dr. VO VAN NHAN
In implant technique, sinus and bone grafts have become a conventional method in dental treatment for patients who lose teeth behind the jaw for the purpose of providing sufficient bone volume for implants.
This technique was first introduced by Dr. Boyne in the 1960s to increase posterior bone volume, followed by trimming the soft bone and soft tissue in this area to create a gap between tow jaws for the traditional removable prosthesis.
In patients with edentulous, downward ethmoidal sinus and large maxillary tuberosity so the gap between the two jaws is insufficient to restore the classic removable denture. Cutting the bone below jaw to create the gap making partial is not feasible, so it is important to lift the sinus and bone graft, and then cut the bone and soft tissue in this area to make the gap between the jaws.
At this point, Boyne entered the sinus through Cadwell-Luc, using self-assembled bones from the iliac crest, after 3 months of healing conducted for soft tissue and tuberosity cutting enough prosthetic space.
Thus, the sinus lift and bone grafts were first used for classical partial dentures.
In the late 1970s, this technique was used to place an implant (blade implant) to perform implant-assisted prosthetis (fixed or removable).
In 1980, Boyne and James presented the technical details and results of three successive bone grafts and sinus lift for implant-supported restoration and 11 cases of bone graft for the classical removable denture.
Then the technical innovations were born so far having two main techniques are internal and external sinus lift.
Maxillary sinus belonging to nasal sinus system included frontal sinus, ethmoid sinus, sphenoidal sinus, and maxillary. In this essay, we introduce the anatomical structure and physiology of maxillary.
Maxillary sinus: the pyramid-shaped, the largest of the sinuses, within the body of the maxilla
•Antral floor: slightly below the level of the nasal cavity
• Apex: peak long to the cheeks of maxillary
• Anterior surface: the facial surface of the body
• Interior surface: alveolar process
• Posterior surface: the infratemporal surface
• Superior surface: the orbital surface
Figure 1: 3D images of the nasal cavity  Figure 2: The bone of the skull 
Figure 3 Standing through the sinus cavity  Figure 4: Vertical line through the sinus cavity 
For people having teeth, the sinus floor below the floor of the nose about 1 cm (McGowan 1993)  and the deepest at the first molar. Upper jaw teeth often cause the ridged of the sinus floor.
- The sinus volume: Until the permanent teething the sinus size is negligible. The volume of the gas chamber develops completely at the end of its development, about 12.15 cm 3 in adults (Chanavaz 1990; Mc Gowan et al. 1993). The volume varies from 4.5 to 35.2 cm3, which means that the volume varies greatly with age and after tooth loss.
• Middle size:
Anteroposterior spread: 38-45mm
Height: 33-45mm (Eckert Mobius1954) 
• The front of the maxillary sinus extends to the 3rd or 4th tooth and the back is the 8th tooth.
• The size and shape of the sinus are different for each person and for the same person. In case of loss of teeth, the maxillary sinus enlargement invades the alveolar bone, in some cases forming the lateral bone, and the posterior crest is thin as paper. 
• The inside of the sinuses is lined with a thin, mucosal epithelium of continuous epithelial tissue, with continuous nasal mucosa (Ritter & Lee 1971; McGowan et al. 1993). 1mm) and less blood vessels than the nasal mucosa.
2.2 The sinus rhythm
• In the healthy physiology of the sinuses, the epithelium of the pubic hair has the function of transporting fluid, such as pus or mucus, to the outside of the natural hole (ostium) located in the middle of the nose.
• The normal function of the sinus depends on the susceptible balance between the production of fluid and the translation of the epithelial hairy tissue epithelium, the ventilation of the sinuses, and the diffusion of dirt through the natural hole. .
• Any factors that interfere with one of these factors will affect the health of the jaw.For example: polyps, tumors and mucosal hyperplasia, or foreign material including grafts (in the case of a collapsed graft).
• Sinus elevation and bone grafting do not affect the function of the sinus when performed on healthy sinuses.However, when the sinuses have pathological factors contributing to stagnation of the translation, bacteria reproduce the condition of sinusitis worsening.Therefore, local diseases are contraindicated relative or absolute when the sinus lift should be carefully considered before surgery.
3.2 Blood vessels providing sinus function:
Out of the external carotid artery, there are 6 branches and 2 branches, namely the shallow temporal artery and the upper artery. The upper artery artery for several branches of which four branches provide blood for the sinus are:
· Artery under the eye
The posterior artery artery
· Female butterfly artery. 
Inferior artery artery: 1.6 mm at the site of the maxillary artery, divided into 2 branches: the gingival branch (branch of the bone) and the branch of the tooth (branch of the bone). upper jaw and bone membrane.
Oral artery: 77% of the cases originate from the maxillary artery and 33% from the common stem with the posterior artery artery, with an average diameter of 1.64 mm.An under-artery artery in the sinus cavity through the opening of the lower abdominal cavity.
According to Solar, the two major arteries that provide sinus arteries are the posterior artery artery and the subclavian artery, and they are usually joined together into two joints.Circles in the bone: Located in the lateral wall of the sinus, providing blood to the sinus membrane and the center of grafting should be very important.Osteosarcoma: located on the vestibular front of the rectum, providing oral mucosal blood, large peritoneal mesentery and small molars.The distance from the bone to the connective ring in the bone is 19mm, to the outer ring of bone is 24mm.This distance varies from person to person and varies from left to right on the same person and changes a lot when missing teeth.Therefore, this index can not be used to refer to the purpose of avoiding blood vessels during surgery.However, in the practice of lifting the sinus often cut into the two rings.
Therefore, for prophylaxis of traumatic bones, the longitudinal line should be reduced as short as possible and the bones should be carefully removed. blood levelTo prevent branch trauma in the bones, the sinus cavity window should be as small as possible and should have a CT scan to determine the blood vessels before surgery. 
3.3 Sinus Infections
• Butterfly: Sperm in the butterfly
• Upper jaw: drainage through the upper jaw in the middle jaw
• Sinusitis: sinusitis, nasal congestion
• Another important structure is the bone niche, which allows circulation between the sinuses and includes the natural opening of each sinus.The circulation between the sinuses, each of the sinuses through the ventricles or the sinuses, is the normal physiology of the sinus, any agent that prevents the circulation will cause sinus congestion, Normal sinusitis and sinus disease.
• Front: venous drainage
Rear side: through the lateral branch of the maxillary vein (parallel artery junction)
• At the infratemporal fossa, the upper jaw connects to the sphincter plexus, which dislocates from the cortex through the skull base.Thus, infection from the sinus cavity may enter the skull and result in meningitis or brain disease. 
3.4 Sinus function
The function of the sinus cavity is not clearly understood.Although it can increase voice resonance, smell, warm and moisten the air as it breathes in, reducing the weight of the skull (Ritter & Lee1978; Blanton & Biggs 1969).
• The upper, middle, and lower nasal bones protect the jawline, filter, moisten and warm the inhaled air.
• Sinusoidal drainage through the nasal cavity, with multiple extra holes (25-30%), ostium hole diameter: 2- 4mm. 
Classification according to location into the sinus:
- Transalveolar approach: into the sinus cavity through the insertion of implants
- Lateral window approach: into the sinus by opening the sinus window on the side.
Sort by implant timing:
- One stage technique: lift the sinus and place the implant at the same time.It is possible to apply sinus lift or open sinus surgery.
- Two stage technique: lifting of the bone cavity awaiting maturation of the bone after implant placement, only applied with open sinus surgery.
Geurs et al., 2001  concluded that statistically significant differences in implant failure when the bone height remaining from the ossicular crest to the sinus cavity were less than or equal to 4 mm when compared to the The bone height is greater than or equal to 5mm.
Therefore, applying the technique 1 or 2, the technique of lifting or lifting open depending on the height of the bone from the crest of the bone to the bottom of the sinus for implant to achieve good initial stability.But initial stability depends on many factors such as the implant design, the surgeon's clinical skill and the bone quality and quantity of the patient. This problem has caused a real-life debate. was implanted in the world 15 years ago and was eventually resolved by the consensus meeting on sinus elevation in 1996. At the consensus meeting there were a total of 900 patients with raised sinuses and selected 100 patients with full film and image quality assurance to evaluate.
Of the 100 patients selected, 145 were raised and bone transplanted, 349 implants were placed, followed by 3.2 years
Results: 20 implant failures including:
+ 13 implant failure when bone height is left: ≤ 4mm
+ 7 implant failure when bone height left: 5 - 8mm
No implant failure when the remaining bone height: ≥ 8mm
The conference also concluded that the remaining bone height was the determining factor for the success of the implant and also recommended the following technical options:
• RBH: Residual Bone Hight (bone height remaining)
• Type A: RBH: ≥ 10mm: place the implant as normal
• Type B: RBH: 7-9mm: tighten the sinus and place the implant (1 st technique)
• Class C: RBH: 4 - 6mm: open sinus surgery, 1 st or 2 stroke technique
• Type D: RBH: 1 - 3mm: open sinus surgery, 2-stroke technique
However, 10 years later in 2006, the clinical skills as well as experience of the surgeons have improved significantly, Dr. Ronald M.'s group made the recommendation harder and had the same content. after:
Self-grafting material is considered to be the gold standard for maintaining cell viability and bone formation.This reduces the waiting time for the growth of bone grafts.
Over time, many types of grafting materials have been introduced, such as: bones of the same species, bones of ancestral or synthetic materials are used separately or mixed together.
Alternative materials reduce the amount of bone itself and also provide good clinical results.
5.1 Contraindicated relative
• Sinusitis caused by viruses, bacteria, fungus, allergic sinusitis, sinusitis caused by strange objects in the sinuses, sinusitis is caused by infections caused by teeth.
Bone tumors of the upper jaw complex are: papillomatosis, schwannomas, bone tumors, polyps, or cysts.
5.2 Absolute contraindications
Severe sinus irregularities can not be reversed
• Sinus mucosal function or scar due to trauma or surgery before.
Radiotherapy of head and neck over 45 Gy
Chronic sinusitis with or without polyps and not responding to internal or surgical treatment.
• Signs of systemic granulomatosis, such as granulomatosis.
Benign, benign but progressive lesions such as ameloplasma, myoma, desmoplastic fibroma, inverted papilloma,
Acute, primary or metastatic neoplasm derived from epithelial, connective tissue or teeth (eg, squamous cell carcinoma, esthesioneuroblastoma, adenoid cystic carcinoma, sarcoma).This is a tumor that requires a large cut when treated, so it permanently loses mucus transfer function.
Complications during the sinus lift can be divided into three stages: surgical complications, early complications after surgery and late complications after surgery are listed in the following diagram:
Complications in surgery , including:
Bleeding from the bone, sinus membrane or cheekbones of the cheek due to cuts in the connective branches in the bones and branches outside the bones of the arterial and posterior arteries of the artery.In order to prevent this complication, it is necessary to make a careful flap, flip flap close to the bone, vertical incision as short as possible, should not perform the incision to release the bone membrane to reduce the base, should CT scan to determine the blood vessels And open the sinus window as small as possible.
Trauma to the nerve endothelium in the lower abdomen may be due to overturned flaps and pressure vessels pressed against the area.This trauma can cause temporary loss of the left and lateral areas of the eye.Prevent this complication flip flops not too high and careful roll.
Perspiration: is the most common complication during the sinus lift, with rates ranging from 10 to 40%, even to 58% .Fibrosis leads to complications after surgery such as: bacterial invasion, increased rates of sinus infection or chronic, swollen, bleeding, wound openings, loss of grafts, sinus congestion, normal physiological function of the sinus.According to Khoury, 1999 and Proussaefs, 2004  dementia was associated with implant failure.
However, some authors, Schwartz-Arad, 2004 and Shlomi, 2004,  argue that there is no association between pericardial effusions or complications with implant survival.Risk factors for increased episodes include sinus cavity flooring, presence of septum in the sinus, sinus membrane (0.3-0.8mm) or swelling, narrow sinus .Rotating instruments have a greater risk of sinus rupture than ultrasonic instruments, and surgical skills also affect the rate of sinus rhythm.
Treatment of pericardial effusion : if the perforation is less than 5 mm, bio-Gide, Geistlich, Biomaterials, Wolhusen, Switzerland) or sewn with a Vicryl 6.0 Use 5-10mm diaphragm, which uses a diaphragmatic membrane that combines with the bone marrow from the lateral wall of the sinus opening, if the hole is more than 10 mm in diameter and stops the course of treatment (Aimetti 2001) . bones, but the success rate is very low about 74%.
Early complications after surgery: 
Early complications occurring from day 7 to day 10 after surgery but less common include:
- Open wound, biofilm exposure: can lead to infection, loss of even the loss of grafting materials.Cause due to overstretched flap or restoration on the wound.Prophylaxis of this complication: a good laparoscopic design that does not stretch when sutured and should dent the implant at the wound site.Patients may also be advised to wear a denture 2 weeks after surgery.
- Bleeding at the incision can happen very rarely.
Infection: Swelling in the mouth on the sinus window is most commonly detected first when there is an infection.It usually occurs 1 week after surgery, but may be earlier than 3 days after surgery, sometimes spreading to the lower extremity, polycystic ovary, even meningitis or encephalitis.Active treatment, including antibiotics, drainage, grafting and implantation, should be provided when implants are placed.The CT scan then evaluates and re-implements the transplant 3 to 4 months later.
Probes in the mouth may appear due to sinus infection, if small, usually respond to antibiotics and gargle with chohexidine, if larger, surgery to close the probe.
Late complication after surgery: 
Delayed complications of sinus transplants may occur 3 months after surgery but are rare, most occurring in the 1st trimester of the 2nd trimester.
- Loss of part or all of the grafts due to an open wound infection above the sinus cavity.This treatment includes antibiotics, drainage, partial or total grafting, covering the sinus cavity with a bio-membrane before closing the flap.
Implant failure due to bone loss may also be due to insufficient volume or bone density to stabilize the implant.Implant moves sooner or later after surgery.
- Invasions of soft tissue in one of the surgery due to not using biofilm to prevent soft tissue invasion into the window into the sinus.Influence of bone growth leads to bone loss.
- The development of the epithelial cyst after surgical removal of the sinus lift, this capsule was first reported by Kubo in 1927 , which is thought to have originated from the small epithelium clamped in during closure wound.It is referred to by many different names: postoperative cysts, postoperative follicular cysts, follicular mucosa, nasal fistula following surgery.Treatment: take the whole follicle, bone graft into the cavity of the cyst.
In addition, the second mouth may also occur during this period.
Sinus elevation and bone grafting to increase bone volume for prosthetic restoration on implants is a common procedure with good prognosis but requires analysis of important factors before surgery including:
Selecting the right patient is the standard for success.
Evaluation of sinus anatomy structure: The bone marrow infiltration, functional status of the nasal sinuses, blood vessels in sinuses, sinus walls, ...
Assess the remaining bone status, select the appropriate technique.
Prevention and management of possible complications.
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