Orthodonticさまざまな動きに使用される歯科矯正用固定ネジ anchoring screws (OASs) used for various movements are simple to use and reliable. OASs are frequently employed as absolute anchorage devices in the buccal interproximal areas of upper and lower jaws, and the mid-palatal area for en masse retraction of the anterior teeth and distalization of the dental arch. Therefore, information about OAS stability) は、使いやすく信頼性があります。OAS は、前歯の一括後退と歯列弓の遠位化のため、上顎と下顎の頬側歯間領域、および口蓋中央領域の絶対固定装置として頻繁に使用されます。したがって、OAS の安定性に関する情報は、歯科矯正治療の成功にとって非常に重要です。

挿入トルク (IT)は、 is exceedingly important for the success of orthodontic treatment. Insertion torque (IT) has been considered one of the factors affecting OASの安定性に影響を与える要因の stability1 ^[1][2][3].つと考えられています Screws[ used1、2、3 in]。歯列矯正で使用されるネジは、一般に直径 orthodontics generally have a diameter of 1.0– ～ 2.3 mm and a length of 3–、長さ 3 ～ 15 mm ^[4][5][6].です [ Motoyoshi4、5、6 et]。本吉ら。[ al.7 ^[7]] investigatedは φ1.6 × 8 mm OASs and recommended that the optimal IT was 5– を調査し、最適な IT は 5 ～ 10 Ncm and this range has been adopted by many clinicians and researchers. However, there have been variations in the literature. A previous study used tapered, self-tapping, であると推奨しており、この範囲は多くの臨床医や研究者によって採用されています。ただし、文献にはバリエーションがあります。以前の研究ではテーパー付きセルフタッピング φ2.0 × 6 mm OASs, and reported ITs of が使用され、IT が 25.6 ± 5.5 Ncm ^[8],と報告されました whereas[ another8 study] used cylindrical, self-drilling, が、別の研究では上顎に円筒形セルフドリリング φ1.5 × 7 mm OASs in the maxillary buccal alveolar area and reported ITs of が使用されました。頬歯槽領域であり、ITs は 6.0 ± 3.2 Ncm ^[9].と報告されています Thus,[ the9 ]。したがって、IT values vary greatly with the placement method and OAS design (screw diameter, length, and tapered or cylindrical form値は、配置方法と OAS の設計 (ネジの直径、長さ、テーパー形状または円筒形状) ^{[1][5][6][7][8][9][10][11][12][13][14][15]}.によって大きく異なります Therefore,[ clinicians1、5、6、7、8、9、10、11、12、13、14、15 may]。したがって、臨床医はこれらの値を実際に適用することを躊躇する可能性があります。

たとえば、口蓋中央領域には隣接歯間領域の骨よりも厚い皮質骨が含まれているため、より高い be hesitant to apply these values in practice. For instance, the mid-palatal area contains cortical bone that is thicker than the bone in the interproximal area, and thus higher ITs may be more suitable. Moreover, ITs for OASs may be different according to OAS designs or insertion techniques. の方が適している可能性があります。さらに、OAS の IT は、OAS の設計や挿入技術によって異なる場合があります。

ITs and success rates of OASs placed in the buccal alveolar and mid-palatal areas are listed in Figure 12, Figure 23 and Figure 34. However, data from one study [10] were not included because the data for φ1.3 mm and φ1.5 mm OASs in the buccal alveolar area were unified, and separate values were not available.

In self-drilling OASs, the ITs ranged from 6.0 ± 3.2 Ncm [9] to 21.1 ± 2.2 Ncm [15], while the success rates ranged from 64.3% [6] to 100.0% ^[10][15][10,15]. Thinner, cylindrical, φ1.5 mm OASs had the lowest ITs [9], whereas the highest ITs were in the mid-palatal area [15]. Thus, IT in self-drilling OASs was affected not only by OAS diameter but also by the placement site. Short 3.0 mm OASs had the lowest success rates [6]. Therefore, short, self-drilling OASs were found to increase the risk of failure.

Regarding self-tapping OASs, Motoyoshi et al. [7] used tapered φ1.6 × 8.0 mm OASs in the upper and lower buccal alveolar areas. In their study, OASs with a 1.0 mm pilot hole in maxilla (diameter ratio: bone drilling diameter/screw diameter × 100 [%] = 62.5%) and a 1.3 or 1.4 mm pilot hole in the mandible (diameter ratio = 81.3–87.5%) showed ITs and success rates of 7.6–8.9 Ncm and 91.8–95.0% in the maxilla and 8.5–8.8 Ncm and 91.9–100.0% in the mandible, respectively (except for the early-loading adolescent group) [7]. They also stated that the pilot-hole diameter in the mandible was extended from 1.3 mm to 1.4 mm when IT exceeded 10 Ncm depending on bone stiffness or cortical bone thickness. ITs and pilot-hole diameters are likely to affect the success rates in self-tapping OASs [7].

In the mid-palatal area, tapered φ2.0 × 6 mm OASs placed into 1.2 mm (diameter ratio = 60.0%) and 1.5 mm pilot holes (diameter ratio = 75.0%) had success rates of 94.5% (IT = 25.6 ± 5.5 Ncm) and 83.0% (IT not available), respectively, with a significant difference [8]. Therefore, it is suggested that the IT should be controlled, using different pilot-hole diameters in different placement sites with varying cortical bone thickness, to prevent bone and OAS fracture. This contradiction between the results of two studies ^[14][15][14,15] may be explained by the differences in OAS characteristics. One important difference was the diameter ratio for self-tapping OASs (62.5% in the Son et al. [14] study). The tightness for tapered OASs could increase the IT and may be considered equivalent to the ITs observed in self-drilling OASs. Another study by Suzuki and Suzuki [15] used a diameter ratio of 75.0% in self-tapping OASs [15]. Under such conditions, the diameter ratio may cause lower ITs that are not equivalent to the ITs of self-drilling OASs. Another difference was the shape of the OASs. Suzuki and Suzuki [15] used cylindrical self-tapping OASs in contrast to the tapered screws in the Son et al. study [14]. As a result, no significant differences in ITs and success rates were recognized between the self-drilling and self-tapping OASs if the same OAS shape was used. However, an in vitro study using the synthetic bone blocks by Tepedino et al. evaluated the relationship between insertion torque and stability of the self-tapping and the self-drilling OASs and concluded that the self-drilling OASs showed a higher maximum IT than the self-tapping OASs under the same conditions of bone-like support and same inner diameter [2].

2.2. Shapes and Dimensions of OASs

2.2.1. Tapered and Cylindrical OASs

Yooユら。[ et13 al.] ^[13] compared taperedは、テーパー型と円筒型のセルフドリリング and cylindrical self-drilling φ1.5 × 7 mm OASs and reported significantly higher ITs in tapered OASs (8.3 ± 3.7 を比較し、上顎頬側歯槽領域において円筒型 OAS (6.3 ± 2.8 Ncm) than in cylindrical OASs (6.3 ± 2.8よりもテーパー型 OAS (8.3 ± 3.7 Ncm) in the maxillary buccal alveolar area. They reported noの方が有意に高い IT を報告しました。彼らは成功率に有意差はないと報告した [ significant13 differences in success rates ^[13].]。 Suzukiスズキとスズキ and[ Suzuki15 ^[15]] usedは、同じ寸法（頬側歯槽領域では tapered (self-drilling) and cylindrical (self-tapping) OASs of the same dimension (φ1.5 × 8 mm in the buccal alveolar area, and 、口蓋中央部では φ1.5 × 6 mm in the mid-palatal suture area), and found that tapered OASs had higher ITs (12.1 ± 3.1 Ncm, 15.7 ± 2.3 Ncm, and 21.1 ± 2.2 Ncm, respectively) than cylindrical OASs (7.2 ± 1.4 Ncm, 12.4 ± 1.2 Ncm, and 14.5 ± 1.6 Ncm) in all）のテーパー型（セルフドリリング）および円筒型（セルフタッピング）OAS を使用しました。縫合部）、テーパ状 OAS の IT が円筒形 OAS（7.2 ± 1.4 Ncm、12.4 ± 1.2 Ncm、14.5 ± 1.6 Ncm）よりも高いことがわかりました（それぞれ 12.1 ± 3.1 Ncm、15.7 ± 2.3 Ncm、21.1 ± 2.2 Ncm）。 ) すべてのサイトにあります [ sites15 ^[15].]。 In an in vitro study, 研究で、Assad-Loss etらは、[ al.16 ^[16]] evaluatedは、いくつかの the fracture torques for several OAS designsOAS 設計 (φ1.5– ～ 1.6 × 6– ～ 7 mm) andの破壊トルクを評価し、結果に最も影響を与える特性は内径と外径の比であると報告しました。クーニャら。[ reported17 that] the characteristic that most influenced the results was the ratio between the internal and external diameters. Cunha et al. ^[17] compared ITs in tapered and cylindrical は、低密度および高密度の牛骨を使用してテーパー型と円筒型の φ1.6 × 8 mm OASs using low- and high-density bovine bone and reported that tapered OASs had higher ITs than cylindrical OASs in the high-density bone,の IT を比較し、高密度骨ではテーパー型 OAS の方が円筒型 OAS より IT が高いと報告しましたが、低密度骨 [ but17 there were no significant differences in the low-density bone ^[17]. ]。

2.2.2. OAS Dimensionsの寸法

AChen らによるin vitro研究。[ study21 by] Chen et al.は、密度 20、30、および 40 ^[18] examined the mepchanicalf properties of の人工骨を使用した φ1.3 × 7 mm OASs (self-drilling) using artificial bone with densities of 20, 30, and 40 pcf, and reported ITs of 3.9, 5.2, and (セルフドリリング) の機械的特性を調査し、それぞれ 3.9、5.2、および 10.0 Ncm, respectively. の IT を報告しました。

Large ある研究で口蓋中央縫合領域に使用された大型のφ2.0 × 6 mm OASs used in one study in the mid-palatal suture area had a success rate of は、94.5% and the highest ITsの成功率と最高の IT (25.6 ± 5.5 Ncm) ^[8].を示しました An[8] in(図4 vitro study by )。Nienkemper らによる et al.in vitro 研究。[ 23 ^[19]] evaluatedはブタの骨盤を使用して φ2.0 × 9 mm OASs using pig pelvic bone and reported that the ITs for insertion depths of 4 mm, 5 mm, and 6 mm were を評価し、挿入深さ 4 mm、5 mm、および 6 mm の IT が 15.4 ± 7.0 Ncm, 、26.2 ± 10.4 Ncm, and 、および 27.2 ± 14.1 Ncm, respectively. Considering であると報告しました。それぞれ。これらの結果 [ these23 results] ^[19], the high ITs of を考慮すると、φ2.0 × 6 mm OASs ^[8]の高い mayIT be[ appropriate8 for] regions with high-density bone, such as the mid-palatal suture area.は、口蓋中央縫合部などの高密度骨領域に適している可能性があります。

2.3. Placement Location

2.3. 設置場所

2.3.1. Buccal Alveolar Area頬歯槽領域

The頬側歯槽領域は、手順が簡単で固定が有利であるため、歯科矯正診療において buccal alveolarOAS が頻繁に設置される部位です。本吉ら。[ area7 is] a frequent site for OAS placement in orthodontic practice because of the simplicity of the procedureは、φ1.6 mm OAS の成功率を向上させるために 5 ～ 10 Ncm の IT を推奨しました。この領域[ 1、6、7、8、9、10、11、12、13、14、15 and]では直径 advantageous anchorage. Motoyoshi et al. ^[7]1.3 ～ 1.7 recommended が使用されているため、さまざまな条件に対する参照ITs範囲が望ましいと考えられます。 これらの研究に基づいて、この領域ではφ1.5〜1.7 ofmmのOASが一般的に使用され、上部および下部頬歯槽領域の円筒形OASにはそれぞれ5〜8 5–10 Ncm to improve the success rate of φ1.6 mmNcmおよび6〜12 NcmのITが最適でした。テーパー付き OAS の場合、IT は 6 ～ 12 Ncm および 8 ～ 15 Ncm が最適です。

2.3.2. 口蓋中央部

口蓋中央領域への OASs. As diametersの配置は、前歯の後退や上顎弓における臼歯の侵入、遠位化、突出など、さまざまな目的に使用されます [28 of]。この領域への 1.3–1.7OAS mm wereの配置は、解剖学的にも隣接歯間領域よりも好ましいと考えられています [ used29 ]。ただし、Naya-Imainらによって報告されているように。[ 30 this]、成人でも縫合糸の閉鎖が不完全である可能性があるため、OAS area留置前にコーンビーム ^{[1][6][7][8][9][10][11][12][13][14][15]},CT aなどの適切な画像診断を使用して口蓋正中縫合糸の縫合深さを考慮する必要があります。この点に関して、彼らは、未縫合領域への挿入を防ぐために、口蓋中央縫合糸での reference OAS の留置は年齢に関係なく避けるべきであると結論付けました。 口蓋中央領域は、特に正中縫合糸に近い皮質が厚いため、IT range制御のために for variousOAS を配置する前に事前のドリリングが必要になることがよくあります[ conditions8、15 would]。スズキおよびスズキ be[ desirable. Based15 on] these studies, φ1.5–1.7 mm OASs were commonly used は、この領域で円筒形とテーパ状の OAS (φ1.5 mm) の両方を使用し、前者の方が IT が低いと報告しました。円筒形 OAS の IT と成功率は、それぞれ 14.5 ± 1.6 Ncm と 100.0% でした。 in vithis area, andro 研究では、Wilmes et al. [ ITs26 of] 5–は、φ1.5 mm およびφ2.0 mm OAS の破断時の最大トルクがそれぞれ 20.1 ± 3.8 Ncm and 6–12 Ncm were optimal for cylindricalおよび 49.2 ± 7.5 Ncm であると報告しています。Dalla Rosaらによるin vitro研究では、[ 27 ]、φ1.5 mm OASs in the upper and lower buccal alveolarの破壊までの降伏トルクは 16.3 ± 1.6 Ncm でした。これらの研究に基づいて、スズキおよびスズキ [ 15 areas, respectively]によって報告されたφ1. For tapered OASs, ITs of 6–15 mm OAS の IT 21.1 ± 2.2 Ncm and 8–1は降伏トルクを超えました。したがって、口蓋中央縫合部には、IT が 20 ～ 25 Ncm were most suitableの φ2.0 mm テーパー OAS の使用が適していると考えられます。

2.3.2. Mid-Palatal Area

OAS placement in the mid-palatal area is used for various purposes, such as the retraction of anterior teeth and intrusion, distalization, and protraction of molars in the maxillary arch ^[20]. OAS placement in this area is also considered anatomically more favorable than the interproximal area ^[21]. However, as reported by Naya-Imai et al. ^[22], the sutured depth of mid-palatal suture should be considered using adequate imaging, such as cone-beam computed tomography, before OAS placement because there could be incomplete suture closure even in adults. Concerning this matter, they concluded that the OAS placement in mid-palatal sutures should be avoided regardless of age to prevent the insertion into unsutured areas.

The mid-palatal area has a thicker cortex, especially close to the median suture, which often requires pre-drilling before OAS placement for IT control ^[8][15]. Suzuki and Suzuki ^[15] used both cylindrical and tapered OASs (φ1.5 mm) in this area and reported lower ITs for the former. Cylindrical OASs had ITs and success rates of 14.5 ± 1.6 Ncm and 100.0%, respectively. 

In an in vitro study, Wilmes et al. ^[23] reported that the maximum torques at the time of fracture for φ1.5 mm and φ2.0 mm OASs were 20.1 ± 3.8 Ncm and 49.2 ± 7.5 Ncm, respectively. In an in vitro study by Dalla Rosa et al. ^[24], the yield torque to fracture for φ1.5 mm OASs was 16.3 ± 1.6 Ncm. Based on these studies, the ITs of 21.1 ± 2.2 Ncm for φ1.5 mm OASs reported by Suzuki and Suzuki ^[15] exceeded the yield torque. Therefore, the use of φ2.0 mm tapered OASs with ITs of 20–25 Ncm is thought to be suitable in the mid-palatal suture area.

2.3.3. Infrazygomatic Crest and the Buccal Shelf Areas頬骨下縁と頬側棚領域

The infrazygomatic crest and the buccal shelf area have some clinical advantages over alveolar interproximal areas ^[25][26], but few studies have investigated OASs in these sites. Sreenivasagan et al. ^[3] investigated the ITs of OASs (φ2.0 × 12 mm) in these areas and found that the ITs and success rates at the infrazygomatic crest (12 screws) and buccal shelf (four screws) areas were 10.1 Ncm and 83.3%, and 10.3 Ncm and 100.0%, respectively. Approximately 10 Ncm IT is considered optimal in these areas, but further studies are required to investigate these placement sites.

3. Conclusions

頬骨下稜および頬側棚領域には、歯槽隣接面領域に比べていくつかの臨床的利点がある[ 33、34 ]が、これらの部位のOASを調査した研究はほとんどない。スリーニバサガンら。[ 3 ] これらの領域の OAS (φ2.0 × 12 mm) の IThe studies included in this  are indicated as follows. The ITs and success rates rangedを調査したところ、頬骨下縁 (ネジ 12 本) および頬棚 (ネジ 4 本) 領域での IT と成功率は 10.1 Ncm および 83.3% であることがわかりました。それぞれ10.3Ncmと100.0%。これらの領域では約 10 Ncm IT が最適であると考えられていますが、これらの配置場所を調査するにはさらなる研究が必要です。

3. 結論

IT fromと成功率は、上部頬側歯槽領域と下部頬側歯槽領域でそれぞれ 6.0 ± 3.2 Ncm to～ 15.7 ± 2.3 Ncm and from 、62.5% to～ 100.0% in the upper and lower buccal alveolar areas, respectively. For the mid-palatal area, the range was の範囲でした。口蓋中央領域の場合、範囲はそれぞれ 14.5 ± 1.6 Ncm to～ 25.6 ± 5.5 Ncm andおよび 83.0% to～ 100.0%, respectively. ITs of 5– でした。一般的に使用されるφ1.5～1.7 mmのOASでは、上部歯間領域と下部歯間領域でそれぞれ5～12 Ncm and 6–と6～14 Ncm were found to be optimal for the commonly used φ1.5–1.7のITが最適であることがわかりました。口蓋中央縫合領域では、テーパー付き φ1.5 mm および φ2.0 mm OASs in the upper and lower interproximal areas, respectively. In the mid-palatal suture area, ITs of 11–1 には、それぞれ 11 ～ 16 Ncm and 20–および 20 ～ 25 Ncm were considered suitable for tapered φ1.5 mm and φ2.0 mm OASs, respectively.の IT が適切であると考えられました。