The author:
Kobyakov Aleksandr Vladimirovich
A maxillofacial surgeon
The principal place of work:
N.I. Pirogov Regional Hospital,
the Division of Maxillofacial Surgery;
the Department of Dental Surgery and Maxillofacial Surgery of N.I. Pirogov Vinnitsa National Medical University
After teeth are lost, atrophy of the mandibular bones, in particular of their alveolar ridges, takes place in some time. This makes the process of the patients’ rehabilitation with the help of dental implants much more complicated and longer.
One of the most popular and successfully applied augmentation methods for a lower alveolar ridge at its vertical atrophy is the segmental sandwich osteotomy (SOO, inlay technique). Though, it should be noted that the important condition of this surgery is the presence of at least 4mm alveolar ridge above the inferior alveolar nerve, which is connected with its possible damage during the surgery as well as with great possibility of the fragment fracture at its fixation with the help of a screw and dam in a case if its width is not enough.
Clinical case
A patient H., 53 years old, complained of missing teeth in the posterior mandible. It is seen from the medical history that the teeth were extracted because of curiosity complications more than 8 years ago. No comorbidity is present.
Objectively: At the examination of the mouth a free-end edentulous space in the right mandible with a distinct right posterior lower alveolar ridge atrophy up to the level of the mucogingival fold is seen (Fig. 1).
Cone-beam CT shows significant reduction of the alveolar ridge measurements in the right posterior mandible. The vertical measurements of the right posterior lower alveolar ridge in the area of the missing teeth 46, 47, 48 above the inferior alveolar nerve vary from 5.5 to 6.7mm (Fig. 2), which corresponds to C-h class according to Misch-Judy (Bone atrophy classification, 1985).
Taking into account that the height of the alveolar ridge is not enough for minimal implant placement, the decision was taken to conduct vertical augmentation of the right lower alveolar ridge using the sandwich osteotomy technique.
Surgery
Under block anaesthesia with 4% Ultracain solution, 4ml, after the processing of the surgical area with Betadine solution, a full cut in the facial surface mucosa of the right lower alveolar ridge was made. Making the distance 3-4mm from the ridge top apically, the surgeon lifted the mucoperiosteal flap with an elevator and marked the line of the future osteotomy considering the position of the inferior alveolar nerve (Fig. 3). A split of the lower jaw cortical lamina was made along the line with a carbide burr. The final mobilization of the bone fragment was made with the help of an osteotome and with preservation of the soft tissue fastening in the area of the ridge top and its lingual surface (Fig. 4). The fragment was mobilized to the maximum, 3-4mm coronal relocation took place then (Fig. 5). Fixation of the fragment in the new position was made with the help of titanium microplates and screws (Fig. 6). The space formed between the fragment where osteotomy took place and the mandibular body was filled with the mixture of a synthetic osteoplastic material Bio3 Beta Bone and a-PRF (Fig. 7). The osteotomy area was covered with several layers of PRF-membranes (Fig. 8). The cut was closed up with a nylon thread (Fig. 9). The check CBCT was made (Fig. 10).
For the postoperational period general analgizing and antibacterial therapy was prescribed. The wound was healed by primary intention, the stitches were taken out on the 10th day.
Placement of 3 implants with immediate loading in 6-8 months is planned.
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| Fig. 1. The free-end edentulous space in the right mandible. The mucogingival fold is situated at the alveolar ridge top (class C-h according to Misch-Judy) |
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| Fig. 2. CBCT of the posterior mandible with vertical measurements of the atrophied alveolar ridge |
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| Fig. 3. The released section of the mandibular with the mark for the further osteotomy |
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| Fig. 4. After cutting the cortical plate osteotomy is conducted with the help of an osteotome |
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| Fig. 5. The mobilized lower alveolar ridge fragment where osteotomy was conducted |
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| Fig. 6. The fragment fixed with titanium microplates and screws |
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| Fig. 7. The formed space filled with synthetic osteoplastic material Bio3 Beta Bone |
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| Fig. 8. The wound surface covered with a layer of PRF-membranes |
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| Fig. 9. The wounf closed up with a continuous suture (polyamide 4.0) |
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| Fig. 10. The check CBCT of the osteotomy area |