盘钻法行上颌窦内提升同期种植体植入的实验研究

【摘 要】目的：本实验以建立动物模型的方法，比较和评估盘钻法与冲顶式行上颌窦内提升牙种植的效果，探求盘钻法行上颌窦内提升的可行性及优势，为其应用于临床提供理论依据。方法：对30个新鲜成年山羊头颅标本随机编号。拔除双侧上颌第三前磨牙及第一、二磨牙，随机选择一侧上颌为实验侧，用盘钻法行上颌窦内提升；另一侧为对照，用冲顶法提升。根据提升高度不同分为三组：A组提升3mm，B组提升5mm，C组提升8mm。同期植入种植体，共计180个位点。对术后形态、黏膜完整度、种植体稳定度、组织学观察进行分析。结果： 实验侧在影像学、形态学、黏膜穿孔率、种植体稳定度均优于对照侧，有统计学意义。结论： 用盘钻法行上颌窦内提升牙种植具有可靠性及可行性，对临床有指导意义。

【关键词】牙种植；上颌窦内提升；盘钻；动物实验

【Abstract】Methods： Thirty fresh skulls ofgoats are numbered randomly. The third premolar， the first and the second molars of bilateral maxillae were extracted. One side of the skulls was randomly chosen as the experimental side， on which the Disk-up Sinus Reamer was applied， while the other side was the control side， on which the osteotome was applied. According to the elevation height， the implantation sites were divided into three groups， namely， 3 millimeters for group A， 5 millimeters for group B and 8 millimeters for group C. There are altogether 180 implantation sites in simultaneous implants. In the wake of the implantation， analysis was conducted as to the shape， integrity of the sinus membrane， implant stability and histomorphological observation.Objectives： The present study aimed to compare and evaluate the outcomes of internal maxillary sinus floor elevation with simultaneous implants placement by Disk-up Sinus Reamer （DSR） and osteotome. The animal model was established， in order to explore the feasibility and superiority of the Disk-up Sinus Reamer applied to internal maxillary sinus floor elevation and to provide theoretical foundation for clinical application.Results： The experimental side is superior to the control side in terms of imaging， shape， membrane perforation ratio and implant stability， providing statistical significance.Conclusions： Internal maxillary sinus floor elevation with dental implants by DSR proves to be reliable and practicable， and will provide guidance to clinical application.

【Key words】Dental implant； Maxillary sinus floor elevation； The Disk-up Sinus Reamer； Animal experiment

1 Material and Methods

1.1 Instruments and equipment

Planter Traus XIP10（Korean SAESHIN Company），W&H 20：1 Light Source Mobile Phone（Australian W&H Company），Disc Drill（Manufacture by self），Stoma D100 Osteotome（German Stoma Company），Osstem GS-II Implant System（Korean OSSTEM Company），Tianbochigu Hydroxyapatite Bio ceramics（Beijing Yihuajiankemao Co， Ltd.），Osstell Resonance frequency analyzer（Sweden Biolin Technology Ltd），Calipers and Dental Caliper（Korean OSSTEM Company），Kadak 2200 Oral X-ray Machine（American Kadak Company）.

1.2 Experimental animals and grouping

1.2.1 Experimental animals choosing

30 fresh skulls ofgoats （provided by Qingdao Wanfu Group Co.， Ltd.）， male or female，36-48 Months of age，requires a complete maxillary dentition，no maxillary sinus disease，saved in 4℃ refrigerator after killed，and be experimented within 24 hours

1.2.2 Experimental animals grouping

Thirty fresh skulls ofgoats were chosen and numbered randomly. We conduct maxillary sinus floor elevation on the bilateral maxillae， totally 180 implants. One side of the skulls was randomly chosen as the experimental side， on which the Disk-up Sinus Reamer was used， while the other side was the control side， on which the osteotome was used. Then all the implantation sites were divided into three groups according to the elevation height.

Group A：at the height of 3mm，totally 60 implants on the bilateral maxillae；

Position：The third premolars of odd number samples the second molars of even number samples；

Group B：at the height of 5mm，totally 60 implants on the bilateral maxillae；

Position：The second molars of odd samples the third premolars of even number samples；

Group C：at the height of 8mm，totally 60 implants on the bilateral maxillae；

Position：Outside wall of the maxillary sinus in all samples corresponds to the first molars.

1.3 Experimental methods

1.3.1 Making tissue sections

Cutting sinus membrane about 5.0mm×5.0mm that away from the elevation site in the maxillary sinus sample， and same size of human the maxillary sinus membrane（provided by Affiliated Hospital of Qingdao University， Oral and Maxillofacial Surgery）， make tissue sections as usual methods.

1.3.2 Maxillary sinus floor elevation

（1）The experimental side

1）Successively to use pioneer drills and reamers in diameter of 2mm， 3mm， and 3.5mm， and make preparation at a safe distance of 1-2mm from the maxillary sinus floor step by step at the sped of 1200 RPM.

2）Use the disk-up sinus reamer （Φ4.0mm） smaller than the implant at diameter of 1mm to drill to the maxillary sinus floor， to cut the sinus floor into dissociative disciform bone fragments. Use depth gauge to determine the depth of drilling and then push up 3mm at the speed of 20 RPM carefully.

3）When the desired elevation height is higher than 3mm put the artificial bone into the implant fossa， until it is filled. Still use the disk-up sinus reamer （Φ4.0mm） to push up at the speed of 20 RPM to elevating the maxillary sinu floor membrane； the process of implanting bone and enhancing is repeated in the rate of 1-2mm each time， finally raised to the desired height.

4）Use the disk-up sinus reamer （Φ4.0mm） smaller than the implant at diameter of 0.5mm as the ending reamer to elevate the floor to the predetermined height.

（2）The control side

1）Insert the NO.1 Stoma Osteotome （Φ2.2-2.7mm） into the fossa and use hammer gently tap the sinus floor into fracture until a sense of hollow. Use the Stoma Osteotome of NO.2 （Φ2.7-3.2mm）、NO.3（Φ3.2-3.7mm）、NO.4（Φ3.7-4.2mm）to tap upward step by step at 1mm each time.

2）When the desired elevation height higher than 3mm， put the artificial bone （TEMB solid hydroxyapatite bioceramic teeth） into the implant fossa， use the Stoma Osteotome of NO.4（Φ3.7-4.2mm）to gently push the sinus floor membrane and bone grants in the direction of the cavity of maxillary sinus； the process of implanting bone and enhancing is repeated in the rate of 1-2mm each time.

3）finally use the Stoma Osteotome of NO.5 （Φ4.2-4.7mm） to elevate the floor to the predetermined height.

Inserting the Osstem GS-II Implant （Φ5.0mm×L10mm）into the prepared implant fossa.

1.3.3 Inserting implant

1.4 Statistical analysis

Use the SPSS17.0 to analyze the experimental statistics， with the methods of chi-square test， analysis of variance， t test and so on， takingα = 0.05， when P> 0.05， no statistically significant； when P ≤ 0.05， statistically significant； when P

2 Results

2.1 Histological Observation

Under microscopic observation： the maxillary sinus floor membranes of both goat and human were mucoperiosteum.

2.2 X-Ray Observation

X-Ray showed that the maxillary sinus floor membranes was elevated in different degrees after the implant operation， forming a ‘hill-like’ protrusion. In no bone implant sites， the root terminal of implant inserted the inside of maxillary sinus floor， and the membranes image was visible with its surface smooth and continuous. In bone implant sites， it showed that high-density bone grafts image was around the endo-sinus of the implants， with continuous and smooth membranes. The endo-sinus part of the implants on the experimental side （elevated by DSR） was closely surrounded by the bone grafts， presenting hemispherical bumps， while the bone grafts were mainly located above the root terminal of the implants on the control side （elevated by Osteotome）， presenting a tent morphology.

2.3 Comparison of perforation ratios

Group A：when elevating 3 mm， there was no significant difference between the perforation ratios of the experimental side and the control side. P>0.05， there was no significant. Group B：when elevating 5 mm， there was no significant difference between the perforation ratios of the experimental side and the control side. P>0.05， there was no significant.Group C：when elevating 8 mm， the perforation ratio in the experimental side was obviously lower than the control side. P

The experimental side，when at different elevation height， there was no significant difference in the perforation ratios of the experimental side. P>0.05， there was no significant.The control side at different elevation height， P> 0.05， there was no significant difference between perforation ration of group A and B.P

2.4 Comparison of the implant stability （ISQ）

Statistical analysis indicated that when the is 3mm， compared the experimental side and ， when the elevation height is 5mm， on the experimental side are higher than the control side’s， and P

2.5 General observation

Carefully open and reveal the maxillary sinus floor membranes at each site. Bone fragments separated from the sinus floor by DSR took on a dissociative disciform shape， with a regular and smooth rim. By contrast， bone chips on the control side were irregular in shape， showing that free piece of bone was jacked up and elevated on one side， while on the other side that is still connected to the sinus bone wall； or the central portion of the bone chip fracture， while surrounding is still connected to the sinus bone wall； bone fragments on were irregular in shape， with acuminate cusps.

3 Discussion

3.1 Build and Design Animal Model

The position， anatomy，and bone physiology of the maxillary sinus and histology physiology of sinus mucosa in goats are similar to humans. Meanwhile， the thickness of sinus floor is also similar to those in maxillary posterior agenesis patients[4].Therefore， goats that are more suitable for experimental study on internal maxillary sinus floor elevation are chosen to use.

In 1994，Summers reported a closed maxillary sinus floor elevation， known as Osteotome Technique[5].Compared with the open maxillary sinus floor elevation， this method reduced surgical trauma， relatively simplified the operation， caused less postoperative reaction. Many scholars have studied the reliability and success rate， and have concluded the success rate of about maxillary sinus elevation in 95 % or more[2-3，6].Now， Osteotome Technique has already become a kind of conventional technique of maxillary sinus floor elevation. At the same time because of the surgical operation area is not visible， only relying on the experience of the surgeon to interpret， it is prone to cause mucosal perforation；and due to the impact of the mouth， the operations in maxillary second molar area are more difficult； The procedure requires striking maxillary sinus floor until fracture， so patients often feel a high degree of tension accompanied by fear and headache， and some even appear benign paroxysmal positional vertigo[7].

In this study， the levels were observed as elevation height of 3mm， 5mm， 8mm， in order to avoid the distance between each upgrade sites so close that mucosal impact the adjacent sites when elevation cause it stripped from bone surface. So， it is designed to planting sites in the third premolar and second molar department and the first molars are spaced from the middle. At the same time， implantation sites elevated 8mm is designed on the side wall of the maxillary sinus， because the side wall of the maxillary sinus can stimulate the remaining bone thickness of 2mm and reduce the workload of trimming the high alveolar bone into residual height of 2mm By that， compare different effect between DSR and osteotome and discuss the feasibility and application conditions of internal maxillary sinus floor elevation by DSR.

3.2 DSR and internal maxillary sinus floor elevation

The characteristic design of DSR is its three kinds of cutting edge：Sharp edge，.Side edge，Twisted edge [11]. Twisted has a strong ability of lateral cutting

Many scholars believe[12-13] ，Osteotome Technique must cause membrane perforation of maxillary sinus floor， and endoscopic observation also confirmed this tear， especially when the elevation height is more than 5mm. In this study， when the elevation height is 3mm or 5mm， the two methods have no significant difference， but when its level is 8mm， the risk of membrane perforation of Osteotome Technique is far higher than that of DSR.

Analysis concluded that there are two reasons for causing membrane perforation by OT. One is that in the early stages of operation， striking the maxillary sinus floor without appropriate intensity can cause membrane perforation， which can be aware by the feel of operators and the blow of patients， and be treated timely. Another one is that in the process， striking the maxillary sinus floor causes the sharp pieces of bone piercing membrane， which is imperceptible. Firstly， the membrane perforation is smaller and there is no obvious symptom. With implants and elevation height increasing，implants can drill into maxillary sinus. Through the general observation of skulls， in this experiment， the reason of membrane perforation belongs to the second case.

Based on this， disciform bone fragment separated from the sinus floor by the sharp edge of DSR is in the middle of membrane and the top of DSR which is propelled upward， so the maxillary floor membrane has gradually been arose. And both bone chips and implants accumulate under the disciform bone fragment. Therefore， buffered drill tip never directly contact with membrane， which makes membrane get effective protection. The drill shank can be mounted directly on a conventional planter application. Through digital display， speed can be accurately controlled， and the torque is kept constant. DSR overcome some disadvantages of osteotome， such as the difficulty to control the intensity， and reduced blindness and suffering caused by striking. In this experiment， using DSP in elevation height 3mm， 5mm， there is no significant difference in the ratio of membrane perforation； while for 8mm， membrane perforation ratio is much lower than OT， which showed good safety.

3.3 DSR and Implants Stability

Initial implant stability reflects the quality and quantity of its surrounding local bone， and is a manifestation of mechanical fitting force. It is generally accepted that the initial implant stability depends on the implant design parameters， the amount of contact between implant and bone， jaw bone， as well as surgical implant technology[16]. This experiment is consistent with the specifications of implants（Φ=5.0mm、L=10mm Osstem GS-II）. Fresh skulls ofgoats were chosen，whose bones are all class II. Operators have proficient planting techniques， so what caused the different value of ISQ between the groups is mainly a different amount of contact between implant and bone.

The contact between the bone and implant at the maxillary sinus elevation sites has two parts； one is contact between implant and sinus autologous bone， and another is the contact between artificial bone implant. The above measurement results in implant stability indicates that the amount of contact between the implant and sinus autologous bone with implant stability was positively correlated， so DSR method increases to enhance stability within a certain range.

The reason is a tool morphological difference. Only the top of the Stoma extruder is concave while the sidewalls are smooth. In the process， the artificial bone meal is mainly pushed towards the direction of the maxillary sinus floor； after implanting， broke into the maxillary sinus part of implant is only the material covered at its root.，while the emptiness surrounding makes the contact area between artificial bone and implant small. But the twisted edge of DSR is anti-twist direction of the thread edge； when it is used， bone debris is pushed into deep cavity， so more autologous bone is preserved， reducing the loss of bone. Thus after implanting， broke into the maxillary sinus part of implant is completely embedded by bone material part， and then the contact area between implants and artificial bone appears at the greatest degree， which leads to the differences in the initial stability of both sides to some extent. Postoperative imaging further confirmed this.

Bur， whether part of artificial bone meal can help speed up the formation and alteration of new bone in implants， and play its role in guiding bone regeneration， and whether the post stage stability of the implant can be enhanced all need further research to confirm.

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