Multiple Perforations of the Sinus Floor During Maxillary Sinus Floor Augmentation to Provide Access to the Bone Marrow Space: A Technical Report

The Use of the Facial Sinus Wall as Bone Shell Onlay Graft for Maxillary Posterior Ridge Reconstruction: A Retrospective Case Series

PURPOSE

To evaluate the performance and clinical outcome of vertical and horizontal bone augmentation (VHBA) in posterior maxillary regions combining lateral window sinus floor elevation (LWSFE) with a horizontal bone shell technique applying the maxillary facial sinus wall as a bone plate.

MATERIALS AND METHODS

In 18 patients, LWSFE was combined with a horizontal bone shield augmentation procedure utilizing the maxillary facial sinus bone wall as a lateral bone plate. Both the sinus cavity and the lateral bone box created were grafted with a mixture of autogenous bone/venous blood and bovine bone mineral. The primary aim was to assess the performance of combined techniques enabling subsequent implant placement. Using radiographic measurements (preoperative, after VHBA, at implant placement, and at follow-up), bone gain/reduction of augmented horizontal ridge width (HRW) and vertical bone height (VBH) were evaluated. Additionally, clinical outcome assessing implant survival/success rate, marginal bone loss (MBL), and implant health (mucositis/peri-implantitis) was evaluated.

RESULTS

For the combined VHBA techniques, HRW and VBH increased significantly (p < 0.001) from preoperative 3.5 ± 1.4 mm/3.6 ± 2.1 mm to 9.7 ± 1.9 mm/18.0 ± 1.6 mm post-augmentation. However, HRW and VBH dimensions decreased up to 8.9 ± 1.8 mm/17.1 ± 1.4 mm at implant placement and 8.6 ± 1.7 mm/16.7 ± 1.3 mm at follow-up evaluation (3.8 ± 1.8 years; p < 0.001, respectively). Augmented bone reduction was significantly higher (-7.7%) between the augmentation procedure and implant placement than in the post-implant-placement period (-2.5%). All implants survived (100%) representing peri-implant MBL of -0.9 ± 0.7 mm, pocket depth of 3.4 + 1.8 mm, and prevalences of 5%/0% for peri-implant mucositis/peri-implantitis.

CONCLUSION

The combination of horizontal bone augmentation using local bone shield transfer from the maxillary facial sinus wall with LWSFE enables sufficient reconstruction of maxillary posterior ridge.

Improved access to the bone marrow space by multiple perforations of the alveolar bundle bone after tooth extraction-A case report

Objectives

The dental alveolus is lined by a thin cortical layer (“bundle bone”, “alveolar bone proper”, “cribriform plate”, “lamina dura”), that can impede access to the bone marrow and its vasculature. During unassisted socket healing, the alveolar bundle bone is gradually resorbed allowing tissue resources from the bone marrow to enter into the socket space. An optimized wound healing process, either during unassisted socket healing or during ridge preservation procedures, with autogenous bone and/or any bone/collagen substitute material, depends at least partly on an adequate vascularization of the socket space. This ensures sufficient recruitment of osteoblast and osteoclast precursor cells and facilitates fast bone regeneration and/or uneventful integration of the augmentation material.

Methods

The present technical note describes an easy treatment step after tooth extraction aiming to improve socket healing with or without any ridge preservation procedure, by facilitating an increased blood inflow into the dental alveolus. Specifically, after tooth extraction the alveolar bundle bone is perforated several times – mainly in a palatally/lingually – by a small round bur (diameter < 1 mm) extending into the trabecular bone.

Results and conclusions

By means of this relatively simple treatment step, an increased blood inflow into the alveolus is achieved after tooth extraction, which might enhance socket healing and corticalization of the entrance, and in turn result in a lower complication rate (e.g., dry socket), in an enhanced graft incorporation, and/or in a reduced loss of alveolar ridge volume.

Variation in bucco-palatal maxillary sinus width does not permit a meaningful sinus classification

OBJECTIVES

The bucco-palatal sinus width (SW) appears as relevant factor for graft consolidation after maxillary sinus (MS) floor augmentation. The present study aimed to assess (a) SW at different height levels of posterior teeth, (b) possible factors influencing SW, and (c) whether a simple/meaningful sinus classification based on SW is possible.

METHODS

The following parameters were recorded on computed tomographies of 76 edentulous and 86 partially edentulous maxillary quadrants displaying 383 tooth sites in total: (a) alveolar ridge height, (b) -area, (c) -width 2 mm apical to the alveolar crest, (d) -width at the sinus floor, and (e) SW and sinus area at a level 2, 4, 6, 8, and 10 mm above the sinus floor. The possible influence of gender, tooth position [i.e., premolar (PM); molar (M)], tooth-gap extent, and residual alveolar ridge dimensions on SW was assessed. Further, based on percentiles of average values or on the frequency distribution of SW <10, 10-15, or >15 mm, it was attempted to classify the sinus at each given site into narrow, average, or wide.

RESULTS

Gender and tooth-gap extent presented no relevant impact on MS dimensions; however, significant differences were observed among the various tooth positions regarding all evaluated parameters. The lower the residual alveolar ridge, the wider the MS at 4-10 mm height, while the wider the residual alveolar ridge, the wider the MS. Large variation in SW classes among the different height levels within the same tooth position and among tooth positions within the same person was observed, irrespective of the threshold applied. Further, at a MS height of 10 mm at PM1, PM2, M1, and M2, SW was <10 mm in 68%, 33%, 0%, and 7% of the cases, respectively, while in 3%, 21%, 65%, and 57%, respectively, SW was >15 mm.

CONCLUSIONS

There is a large variation in SW depending on the height level within the sinus and on tooth position, which does not permit a simple/meaningful classification of each sinus as "narrow," "average," or "wide." Nevertheless, narrow sinuses (<10 mm) are rather prevalent in the premolar region, while wide sinuses (>15 mm) in the molar region; further, a wider and shorter residual alveolar ridge is associated with a wider SW.

Micro-CT evaluation of the cortical bone micro-architecture in the anterior and posterior maxilla and the maxillary sinus floor

OBJECTIVES

To perform a within-subject comparison of the cortical bone micro-architecture of the maxillary sinus floor (MSF) to that of the buccal aspect of the anterior and posterior maxilla.

METHODS

Micro-CT scans of the buccal aspect of the anterior and posterior maxilla and of the MSF in 14 human anatomical specimens were recorded. Within-subject comparisons were performed for cortical thickness (Ct.Th) and porosity (Ct.Po), average pore volume (AvgPo.V), and pore density (Po.Dn).

RESULTS

The MSF presented the lowest and the anterior maxilla the highest Ct.Th, while Ct.Po was significantly higher at the MSF compared to the posterior maxilla (p = 0.021). No relevant differences were recorded for AvgPo.V and Po.Dn among regions (p > 0.067). Further, an increased Ct.Th at the MSF was significantly associated with a lower Po.Dn, while a higher Ct.Th and an increased AvgPo.V in the anterior maxilla were associated with a higher Ct.Th and an increased AvgPo.V, respectively, in the posterior maxilla and MSF. Finally, within each region, the AvgPo.V was associated positively with Ct.Po and negatively with Po.Dn.

CONCLUSIONS

The cortical bone of the MSF is slightly less thick and slightly more porous compared to the cortical bone at the buccal aspect of the anterior and posterior maxilla.

CLINICAL RELEVANCE

During lateral and vertical bone augmentation procedures, the cortical recipient bone is perforated several times to open the bone marrow compartment to facilitate provision of osteoinductive cells and molecules in the augmented space. Whether it is meaningful to approach the MSF in a similar way during MSF augmentation procedures or whether the slightly more porous structure of the MSF observed herein reduces the cortical barrier function already sufficiently has to be assessed in future clinical trials.