For implantation in the maxillary buccal alveolus, precautions must be taken to prevent injury not only to the teeth, but also to the maxillary sinus (figure 2, 3).
The greatest advantage of using buccal alveolus area is the superior accessibility for implantation and utilization. There are two major problems with the use of buccal alveolar implants: the risk of root injury and the limitation of tooth movement. Irreversible root injury is very rare, but it is critical. However, proper treatment protocols, such as pre-drilling through cortical bone by a manual drill, accurate positioning, and oblique insertion can actually reduce or eliminate the risk of root injury.
The second problem is that implants placed in an interdental area may impede mesio-distal movement of the adjacent teeth. But, with proper treatment protocols, including off-center and oblique insertion at the area between the 2nd premolar and the 1st molar, 3mm of mesiodistal tooth movement is feasible. If more than 3mm of movement is needed, re-insertion of another implant may be useful after the teeth have moved 3mm mesiodistally.
When the implant is to be inserted in the areas of the frenum, a frenectomy should be performed to prevent possible mechanical irritation around the implant during function. And indirect approach using contra-angled instruments may be needed in the area between the 1st and 2nd molars.

Caution must be taken to prevent injury to the greater palatine neurovascular bundle and maxillary sinus (figure 3, 16).
For the intrusion of the maxillary molar segment and the arch constriction, posterior palatal implants are necessary for biomechanical efficiency. Additionally, by using abundant palatal space, various attachments can be utilized to change the line of force. Cortical bone is thicker here than in the buccal area, and the keratinized gingiva is thicker. As a result, the incidence of soft tissue problems is very low. There is also more mesio-distal space available than there is buccal space. Furthermore, because transpalatal attachment is not necessary for treatment, there is greater ease of treatment as an application point of palatal force and less patient discomfort than in the midpalatal area.

There is also less accessibility to the palatal area than the buccal area. Hence, the posterior palatal area is not suitable for direct implantation. Because accessibility is lower, more skill may be required comparatively.
Patients should be instructed not to place their tongue over the implant after insertion because this could lead to loosening of the implant as a result of continuous irritation from the tongue.

Antero-posterior positioning:Insertion with a direct view is impossible, so delicate positioning for procedures such as buccal insertion is difficult. The shape of a palatal root is also checked before positioning using panoramic radiography. For posterior intrusion, insertion between the 1st and 2nd molars is recommended. For lingual orthodontic treatment, insertion between the 2nd premolar and 1st molar or between the molars is recommended.

Precautions should be considered to prevent injury to the nasopalantine canal or nasal cavity (figure 24, 25, 26, 27, 28).
The thick cortical bone provides excellent primary stability and the risk of irreversible injuries to anatomical structures is relatively low. In this area, there are no structures that will interfere with orthodontic tooth movement. Additionally, the palatal side provides enough space to allow for the use of lever arms to control the line of action. The condition of soft tissue is also suitable for implantation because the soft tissue in this area is the mucoperiosteum . However, accessibility is poor, and in order to be used for treatment, construction of additional transpalatal attachments may be required. Consequently, the use of transpalatal appliances tends to increase patient discomfort (figure 29). Furthermore, the risk of surgical trauma during implantation is high because of the thick cortical bone and since blood supply is poor, the healing potential is low. Additionally, hard bone renders a high risk of implant fracture during the insertion procedure. Low accessibility makes matters worse.
When using the indirect approach with contra-angled instruments, a long neck driver and a long neck drill should be used to prevent premature blockage by the anterior teeth(figure 31, 32).
The patient will feel "pressure" under the nose during or after insertion.

Anterior-posterior position: To avoid injury to the nasopalatine canal, a lateral cephalogram should be used as a guide and an implant should not be placed in the area 40% anterior to the mid-sagittal plane. Placement in the middle 40% is recommended when considering safety .
Transverse position: The midpalatal area is the place where cortical bone meets (figure 27); thus, bone quality is excellent. In terms of the quantity of bone, implantation on the midplatal suture is desirable.
From the view of bone quality, the results may or may not be desirable. In cases in which the bone quality of the buccal area is inadequate, midpalatal suture areas where cortical bone meets are good for obtaining primary stability. However, the bone quality in the midpalatal suture area may be extremely hard, especially in male patients with low mandibular angles. The stability in these cases would be rather low because of surgical trauma induced by frictional heat and physical pressure from the hard cortical bone. The risk of implant fracture also increases. Therefore, insertion of an implant slightly separated from the mid-sagittal plane or into the para-sagittal plane is preferred where hard bone is expected.
Insertion of an implant slightly away from the mid-sagittal plane is also preferred in cases in which sutural growth is still occurring in growing patients.
Implantation angle: The implant should generally be inserted perpendicular to the bone surface in order to secure the quantity of available bone. When direct insertion is performed, the implant has a tendency to tilt forward due to limitations in opening the mouth, yet slight anterior tilting does not seem to present any clinical problems.
In cases in which one implant is used with an attachment, an implant may be inserted with an antero-posterior angulation or with a lateral angulation for higher resistance to orthodontic forces (figure 30).

In the anterior alveolus, there is comparatively limited available space because of narrow interdental and labio-lingual dimensions (figure 33, 34). Patient discomfort from the implant and stress from the surroundings may be relatively high because of perioral muscle activity. The steep slope of the labial side of the anterior alveolar bone may lead to impingement of soft tissue.
However, the bone quality in this area is favorable and is able to provide good primary stability while also being an ideal position for delivering intrusive forces to the anterior teeth with a labioversion vector.
This is useful in the case of Class II div. 2. Depending on the condition of the frenum, the open method or the closed method should be chosen (figure 35, 36). In the closed method, the implant head is not exposed and only the wire extension is exposed.

The quality and quantity of bone in this area are good for implants. Although the soft tissue is thick, it is keratinized and of good condition. Nevertheless, the tongue is located in this position, so discomfort to the patient or stability during the initial healing period may be affected. Implants in rugae area can be utilized for mesial movement of molars in adult patients, for orthopedic application, and for molar distalization in growing patients. Like any palatal implants, it is advantageous to control the line of action by changing the point of force application.
Following anesthesia, the thickness of the soft tissue should be measured using a periodontal probe prior to implantation using a periodontal probe. The implant should be chosen according to the thickness of the soft tissue.
In the rugae area, the midsagittal plane should be avoided as not to injure the nasopalatine neurovascular bundle.

While there was a low success rate observed in the maxillary buccal alveolus area in the early days of mini-implants, much attention was drawn to the infrazygomatic crest area because of its superior cortical bone quality, which provides higher primary stability. Moreover, the fact that the location of the implant is much higher serves to be advantages. This is favorable for the application of intrusion forces and does not cause any interference to the movement of adjacent teeth. However, because it is in the vestibular area, there is considerable movement of soft tissue and the implant may be covered readily. Not only does this make the open method difficult to apply, but there is also a relatively high risk of the development of soft tissue problems (figure 37). Since the implant is inserted in a higher position, bone quantity may be insufficient, thus increasing the risk of maxillary sinus injury.

Though this is a favorable position for the delivery of distalizing forces, accessibility is poor, and thus, implantation may become inaccurate. Furthermore, bone quality may not be sufficient due to pneumonization of the maxillary sinus, especially in edetulous areas. Pre-surgical examination using panoramic radiography is necessary.