The sinus lift and graft operation is a well-accepted surgical procedure for augmentation of the atrophic posterior maxilla. Before placement of implants, sinus graft augmentation has produced excellent results with few complications. 1–8 The anatomy of the posterior maxilla combined with increased pneumatization of the sinus and progressive alveolar bone atrophy presents a challenge to the clinician for implant prosthetic reconstruction. Insufficient bone quality and quantity, 9 combined with increased destructive occlusal forces, influence the success of implant-supported restorations anchored in the posterior maxilla. 10 An individualized approach to treatment planning with consideration given to anatomic limitations, esthetics, function, and surgical techniques will positively increase long-term success. 11
Bone loss occurs at a faster rate in the maxilla than other areas of the mouth. The initial decrease in bone width after tooth extraction is secondary to buccal bone plate resorption. 12 Bone height decreases with continued atrophy of the edentulous alveolus and is exacerbated by periodontal disease, tooth loss, traumatic extraction, ill-fitting dentures, or apical pathology. Bone density continues to decrease with concomitant fewer trabeculae. 13 As this process continues to a reduced bone height of less than 10 mm and/or a decrease in bone width, ideal implant placement is compromised.
Advances in bone grafting surgical techniques and materials give the clinician several available options to treat problems of the posterior maxilla. 14 The osteotome sinus floor elevation technique, introduced by Summers in 1994, 15 was later followed by the bone-added osteotome sinus floor elevation procedure. 16 The average gain of 3.25 mm in bone height using these techniques has been reported by others. 15–21
The maxillary sinus graft accessed through the alveolar crest was first described by Tatum. 3,4 The procedure was later modified as the lateral wall subantral augmentation osteotomy and graft surgery. 2,5,6,22,23 This operation provided an easier approach to elevate the Schneiderian membrane to deposit the graft material against the alveolus inferiorly, the anterior sinus wall, the medial sinus site, and the posterior sinus region.
Although the lateral wall sinus lift surgery is technically not demanding and is a very predictable surgery, it does have some disadvantages. It is easiest to perform it in the totally edentulous posterior maxilla, but it is technically more difficult to accomplish when adjacent teeth are present. The surgery is more extensive than a minimal socket lift and graft, and is more difficult for a single tooth defect with possible complications of membrane perforation, infection, and loss of the graft.
If only 1 to 3 mm of additional bone height is needed before implant placement, the green-stick fracture technique through a socket lift approach can be performed. The implant placement can be accomplished simultaneously with the graft surgery. The disadvantage of the green-stick fracture technique is limitation of obtainable bone height and tearing of the sinus membrane leading to unpredictable results.
Presurgical Preparation of the Trephine Bone Core Sinus Elevation Graft
Presurgical evaluation is critical for the success of this procedure. Accurate measurement of the distance between the alveolar crest and the antral floor is determined with a computed tomography (CT) scan or diagnostic panographic x-rays (Fig. 1).
When using the panographic x-ray, 5-mm pins are placed on buccal aspect of the surgical template and positioned in the maxilla. The pin is measured on the x-ray. The bone height from alveolar crest to the antral floor is measured. An algebraic equation solves for the unknown exact bone height according to the following formula.
In the authors’ experience, the panographic x-ray with the 5-mm pin surgical template is comparable in accuracy with a CT scan. A minimum of 6 to 8 mm alveolar bone is suggested for the success of the trephine bone graft. Bone height less than 6 mm is best treated with conventional lateral wall subantral quadrilateral osteotomy augmentation.
The sinus should be void of disease. The presence of an antral septum at the surgical site complicates intrusion of the trephined antral core. In addition, there must be 2 mm of bone between the trephine and adjacent teeth as well as 2 mm of cortical bone on the buccal and palatal aspects of the trephine. The curvature and angulation of adjacent roots into the proposed osteotomy site are also evaluated.
Preoperative antibiotics are taken 2 hours before surgery to ensure an adequate level of activity before making the incision. After infiltration of local anesthesia, a linear incision is made on the palatal aspect of the alveolar crest between the edentulous area and the adjacent teeth. A mucoperiosteal flap is reflected from the palatal aspect over the crestal bone and remains pedicled to the buccal mucoperiosteum (Fig. 2).
Measurement of the distance between the alveolar crest and the antral floor is marked on the appropriate-diameter trephine drill (Ace Surgical Supply, G. Hartzell & Son, Salvin Instrument Supply). The trephine is positioned on the alveolar crest permitting 2 mm of cortical bone on the buccal and palatal area. Two to 3 mm distance remains between the trephine and the adjacent tooth (Fig. 3).
With copious irrigation and with gentle pressure, the trephine is drilled to the distance measured from the CT scan or panographic x-ray to the antral floor. The trephine separates the bone core from the alveolar crest (Fig. 4). The core is intruded into the socket lifting the sinus membrane. This is accomplished with finger pressure or with a sharp tap with a mallet and a sized parallel pin. With tactile gentle pressure, care is taken not to aggressively push the core through the membrane into the sinus cavity. The core is intruded to allow one half to one third of the bone core to remain in contact with alveolar bone (Fig. 5).
A 5-wall bony defect remains at the alveolar crest. Autogenous bone surrounds the osseous defect and the trephined core. The crestal osseous defect is grafted with minimal compaction and only enough graft material to fill the osseous defect with CGraft or Orthoblast II (Clinician’s Preference, Golden, CO) (Fig. 6). Overpacking and compressing the graft into the defect will push the bone core through the Schneiderian membrane and into the sinus. The mucoperiosteal flap is repositioned and sutured to the palatal tissue (Fig. 7). Before suturing, the graft site can be covered with a hemostatic wound dressing or a guided bone regenerative membrane. Postoperative x-rays will confirm the superior position of the core (Fig. 8).
If sufficient alveolar bone height is present, this procedure can be done at multiple sites without resorting to the lateral wall osteotomy approach. Healing is usually uneventful, requiring mild analgesics. After 4 to 6 months’ healing, the implant receptor site is prepared and the implant placed (Fig. 9).
Complications and Treatment
On occasion, the core will remain in the trephine. The core is then removed from the trephine and placed within the prepared site. If the membrane is not perforated, the bone core will push against the membrane. Care is taken to add the minimal amount of bone graft to fill the crestal 5-wall defect with a loose compaction. Overfilling of the defect will push the core into the antrum.
If the core is pushed or dislodged into the antrum, there is the potential for an oral–antral opening. Treatment of this complication is done by placing a small collagen hemostatic wound dressing or bone regenerative membrane into the osseous defect. The defect is grafted with appropriate allogeneic, xenograft, or alloplastic material. The crestal region is covered with a resorbable or nonresorbable membrane. The resorbable membrane should remain for a minimum of 4 to 6 months. After healing, the defect can be treated with the sinus-lift operation or another attempt for the trephine socket-lift procedure.
The advantage of this procedure is that it can be accomplished without the large mucoperiosteal flap required for the lateral wall subantral osteotomy. Furthermore, the trephine bone core osteotomy can easily be performed within 10 to 15 minutes of chair time using only local anesthesia. Postoperative pain, discomfort, swelling, and bruising are minimal. Complications are easily treated without adverse or irreversible morbidity. Depending on the height of the alveolar crest, this procedure will permit placing implants of 10 to 16 mm into the edentulous maxillary ridge after healing of the trephined core.
The disadvantage of this procedure is that it does not produce bone stabilization that is buttressed against the medial wall of the sinus. A further limitation is that the superior positioning of the core graft is dictated by the height of the preexisting crestal bone.
The trephine bone core sinus elevation is a predictable surgical procedure with minimal patient discomfort and swelling. The procedure adds sufficient bone height for the placement of implants in the posterior maxilla. It is recommended that the graft be allowed to heal 3 to 6 months before implant placement. The trephine bone core sinus elevation is indicated when teeth are adjacent to the edentulous defect and there is moderate alveolar atrophy. One third to one half of the bone core stays in contact with the walls of the alveolus. A minimum of 6 to 8 mm of alveolar bone helps to ensure success of the trephine bone core sinus elevation graft.
Dr. Dennis Smiler states that he is a consultant and a lecturer for Clinician’s Preference, Inc. The products used are CGraft or Orthoblast II bone graft material. A video of this procedure can be seen by accessing web page Smiler.net.
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Abstract Translations [German, Spanish, Portugese, Japanese]
AUTOR(EN): Muna Soltan, DDS*, Dennis G. Smiler, DDS, MScD**. * Privat praktizierender Arzt, Riverside, Kalifornien. **Privat praktizierender Arzt, Riverside, Kalifornien. Schriftverkehr: Muna Soltan, DDS, 4624 Arlington Avenue, Riverside, Kalifornien 92504. Telefon: 909-682-6486, Fax: 909-682-0301. eMail: [email protected]
Sinusanhebung und Transplantation von Bohrerknochenkernen
ZUSAMMENFASSUNG: Die Sinushöhle lässt häufig nur eine begrenzte Ausnutzung von Knochengewebe zur Einsetzung von Implantaten in den hinteren Oberkiefer zu. Die Methodik der Sinusanhebung und Transplantierung ermöglicht es, mehr Knochengewebstransplantat als 10 bis 16 mm durch Verstärkung der seitlichen Wand in einer quadrilateralen Osteotomie einzusetzen. Bei Vorliegen einer mittelschweren Alveolaratrophie kann eine Osteotomieanwendung einen durchschnittlichen Anstieg der Knochenhöhe von 3,5 mm bringen. Der vorliegende Artikel beschreibt die Sinusanhebung und Transplantation von Bohrerknochenkernen. Mit dieser Methode soll eine Verstärkung der Knochenhöhe um 4 bis 8 mm erreicht werden. Dieser Behandlungsweg ist besonders dann angezeigt, wenn sich im direkten Umfeld Zähne befinden und nur eine moderate Alveoloratrophie vorliegt.
SCHLÜSSELWÖRTER: Zahnhöhlentransplantat, Sinustransplantat, Sinusanhebung
AUTOR(ES): Muna Soltan, DDS*, Dennis G. Smiler, DDS, MScD**. *Práctica Privada, Riverside, California. **Práctica Privada, Encino, California. Correspondencia a: Muna Soltan, DDS, 4624 Arlington Avenue, Riverside, California 92504. Teléfono: 909-682-6486, Fax: 909-682-0301. Correo electrónico: [email protected]
Injerto de elevación del seno con núcleo de hueso con trépano
ABSTRACTO: La cavidad del seno a menudo limita la cantidad de hueso disponible para la colocación de implantes en la mandíbula posterior. La operación e injerto para elevar el seno es una técnica que permite agregar hueso injertado por encima de 10 a 16 mm a través de una osteotomía cuadrilátera en la pared lateral. Sin embargo, cuando está presente una atrofia alveolar moderada, la técnica con osteótomo puede proporcionar un aumento promedio en la altura del hueso de 3,5 mm. Este trabajo presenta el injerto para elevación del seno con núcleo de hueso con trépano que se usa para aumentar la altura del hueso entre 4 y 8 mm. Este procedimiento se indica especialmente cuando los dientes adyacentes están presentes y existe solamente una atrofia moderada del alvéolo.
PALABRAS CLAVES: injerto de la cavidad, injerto del seno, aumento del seno
AUTOR(ES): Muna Soltan, Doutor em Ciência Dentária*, Dennis G. Smiler, Doutor em Ciência Dentária, Mestre em Ciência Dentária**. *Clínica privada, Riverside, Califórnia. **Clínica privada, Encino, Califórnia. Correspondência para: Muna Soltan, DDS, 4624 Arlington Avenue, Riverside, California 92504. Telefone: 909-682-6486, Fax: 909-682-0301. E-mail: [email protected]
Enxerto para Elevação da Cavidade Óssea Central Através de Trefina
RESUMO: A cavidade do sinus freqüentemente limita a quantidade de osso disponível para a colocação de implantes na maxila posterior. A operação e enxerto para elevação do sinus são uma técnica que pode acrescentar osso enxertado além de 10mmm-16mm através de osteotomia quadrilateral da parede lateral. Contudo, quando a atrofia alveolar moderada está presente, uma técnica com osteótomo pode proporcionar um aumento médio na altura do osso de 3.5mm. Este artigo apresenta o enxerto para elevação da cavidade óssea central através de trefina que pretende aumentar a altura do osso em 4mm-8mm. Este procedimento é especialmente indicado quando os dentes adjacentes estão presentes e há apenas atrofia moderada do alvéolo.
PALAVRAS-CHAVE: enxerto alveolar, enxerto do sinus, aumento da cavidade