Implant Placement Surgery Maxillary sinus and success of dental implants: an update Wesam T. Al-Salman, DDS, MSc n Khalid Almas, BDS, MSc, FDRSCS (Edin), FRACDS, DDPH, RCS, FICD The maxillary sinus augmentation procedure has been gaining more accep- Received: August 11, 2014 tance among dental professionals. The aim of this review article is to provide Accepted: December 8, 2014 an update about various aspects of anatomy, physiology, and common pathological conditions of the maxillary sinus and their clinical relevance Key words: maxillary sinus, dental implants, sinus to the sinus augmentation procedure and subsequent implant placement. pathology, sinus complications, sinus graft materials atients suffering from tooth loss in the communicates with the nasal cavity through The average dimensions of the maxillary posterior maxilla are often subject to an opening (called an ostium) that is located sinus are 33 mm in height, 23-25 mm in esthetic, functional, and psychological high on the medial wall and opens into width, and 34 mm in the anteroposterior P 1 14 complications. Maxillary sinus augmenta- the semilunar hiatus of the middle nasal axis; the average volume is 15 mL. tion (also known as sinus lift) procedures meatus on the lateral nasal cavity.7 The blood supply to the maxillary sinus have become increasingly popular proce- The maxillary sinus starts to develop mainly comes from the branches of the dures prior to placement of dental implants as early as the tenth week of gestation as maxillary artery, including the posterior in posterior maxillae that have suffered invaginations of the mucosa and extension superior alveolar and the infraorbital severe bone loss due to sinus pneumatiza- from the primitive ethmoid infundibu- arteries, which anastomose in the lateral tion, alveolar bone atrophy, or trauma. lum.8 During childhood, the maxillary antral wall.12 Additional blood supply to For a clinician to master this surgical sinus has periods of rapid growth: the the inferior part of the sinus may come procedure, he or she requires a thorough first spurt is between birth and 3 years of from the greater palatine artery.15 Nerve knowledge of sinus anatomy, physiol- age, and the second one is between 7 and supply to the sinus is derived from the ogy, pathology, and surgical techniques. 12 years of age.8 The level of the sinus second division of the trigeminal nerve Furthermore, advances in the field of bone floor, determined by its cephalocaudal (maxillary nerve V2) through the superior regeneration necessitate a careful review of pattern of growth, continues to grow alveolar nerve.12 Venous drainage runs available products and their limitations.2 In until it reaches the level of the floor of the anteriorly into the facial vein, posteriorly addition, many clinical trials and reviews nose at 9-12 years of age.9,10 The floor of into the maxillary vein, and into the have investigated the success and survival the antrum in dentate adults may reach jugular vein (via the dural sinus system). of dental implants in different regions of approximately 1 cm below the nasal floor.11 The lymph drainage occurs via the infra- the mouth, but there is little research on The increase in the sinus as a person orbital foramen and the ostium.11 implants after sinus augmentation.3-5 ages is called pneumatization, which Maxillary sinus septa were first men- This article will discuss different aspects results in a pyramidal structure in which tioned by Underwood in 1910.16 He of the maxillary sinus, including sinus the base is oriented toward the nasal wall described them as barriers of cortical bone development, anatomy, physiology, and and lateral apex extends into either the that arise from the floor or the walls of the pathology. The sinus augmentation tech- zygomatic process of the maxillary bone sinus and may divide the sinus into several nique, including elevation procedures, or the zygoma.10,12 Anteriorly, the sinus recesses.17 Based on their origin, septa can regenerative materials, possible complica- extends to the canine and premolar area; be further subdivided into primary septa, tions, postoperative instructions, and post- the most inferior point of the floor extends formed during maxillary development and augmentation implant success and survival to the first molar region. The roof is tooth growth, or secondary septa, acquired rates, will also be reviewed. formed by the orbital floor and transected during the pneumatization of the maxil- by the course of the infraorbital nerve that lary sinus after tooth loss.18 Development, anatomy, and exits through the infraorbital foramen.13 The sinus is internally lined with a physiology of the maxillary sinus Behind the posterior wall is the pterygo- thin respiratory ciliated epithelium that The maxillary sinus, the largest paranasal maxillary fossa, which contains several is continuous with the epithelium of the sinus, serves many functions, including important structures, such as the internal nasal mucosa; however, the antral mucosa air conditioning, pressure damping, vocal maxillary artery, sphenopalatine ganglion, is thinner (approximately 1 mm thick) and resonance, and the reduction of the weight and the greater palatine nerve. The process less vascular.11 The sinus epithelium pos- of the skull or growth of the face. It exists of pneumatization usually leaves a thin sesses cilia that serve in the transportation in most placental mammals and archo- bone in both the occlusal and lateral walls of fluid secretions toward the ostium. This saurs.6 It is located within the bone of the (especially above the canine in the canine lining of the maxillary sinus cavity is called maxilla on each side of the nasal cavity and fossa) of the posterior maxilla.12 the schneiderian membrane (also known www.agd.org General Dentistry July/August 2015 47 Implant Placement Surgery Maxillary sinus and success of dental implants: an update as the sinus membrane).19 This membrane thickening are associated with an increased trapdoor does not exceed the width of is usually elevated when insufficient bone risk of sinus outflow obstruction.26 In such the sinus. An antral curette is used to height is present during dental implant cases, a consultation with an ear, nose, gently lift the sinus membrane from the installation in the posterior maxilla. and throat specialist is recommended. bony floor in 3 directions (anteriorly, However, any degree of thickening with a posteriorly, and medially); lifting proceeds Pathological conditions rounded mucosal appearance is associated from the apicodistal to the coronomesial In general, maxillary sinus diseases can with a low risk of sinus obstruction.26 direction in order to release the tension on be classified as inflammatory, mucocele, Radiographically, pathological lesions on the membrane. The space is then grafted. odontogenic, neoplastic, or granuloma- the sinus may have the following charac- Implants are then placed either simultane- tous vasculitis.20 teristics: soft tissue lesions that are usually ously (1-stage) or after a delayed period of Inflammatory disease is the most radiopaque without a corticated margin; up to 12 months (2-stage) if graft matura- common pathological condition involving sinus walls that present a thin, continuous tion is necessary. The recipient site should the maxillary sinus. Usually inflamma- white line (in benign disease); resorbed not be overfilled, as that may lead to mem- tory diseases are a consequence of upper sinus walls and a discontinuous corticated brane necrosis.12,27 respiratory tract infections that are viral outline (in malignant, infectious, or The 1-stage procedure is less time con- in origin.20 Symptoms may include pain expansile disease); or resorbed roots of the suming; however, it is more technique sen- and discharge. On the other hand, chronic maxillary teeth (in malignant or rapidly sitive. The procedure’s success relies heavily inflammatory disease of the sinus is usually expansile diseases).20 on the amount of residual bone. One of the bacterial in origin and rarely causes pain, drawbacks of the 1-stage technique is that except during exacerbation.20,21 Sinus elevation procedure it requires a large flap for surgical access.12 Mucoceles are epithelium-lined cystic The elevation of the sinus floor is an inter- masses usually resulting from obstruction nal augmentation of the maxillary sinus, Crestal approach of the sinus ostia.22 They may result in intended to increase the vertical bony This technique begins with a crestal inci- a completely filled sinus and can lead to dimension of the lateral maxilla to allow sion.29 A full-thickness flap is then raised bone expansion due to pressure.20 placement of dental implants in sites with to expose the alveolar ridge. Next, an oste- Odontogenic sinusitis accounts for insufficient alveolar bone height.1 The otomy is performed, starting with an osteo- approximately 10%-12% of maxillary procedure was introduced by Tatum at tome of the smallest size, which is tapped sinusitis cases.23 It can occur when the an Alabama dental implant conference in in place in the bone with a mallet or drill. schneiderian membrane is violated by 1976 and was subsequently described by More osteotomes of gradually increasing conditions related to dental pathology of Boyne & James in 1980.27,28 size are then used to expand the alveolus the maxillary bone, infections of the max- The classic sinus lift procedure consists of and compress the bone. Once the largest illary teeth, trauma to maxillary teeth, the preparation of a window in the lateral osteotome has been placed, prepared bone or by iatrogenic causes such as dental maxillary sinus wall. This window is then grafting material is added to the osteotomy extractions, incorrect placement of dental luxated inward and upward with the schnei- so that it presses on the sinus membrane. implants, and maxillary osteotomies in derian membrane to a horizontal position, This additional pressure causes the eleva- orthognathic surgery.24 thus forming a new sinus floor.1 The space tion of the membrane.