兽研摘要
关于引导组织再生（GTR）应用于犬晚期牙周缺损的临床证据有限。本回顾性研究旨在评估重度牙周病犬接受GTR后的临床与影像学结局及牙齿存活情况。回顾了67只犬、共计129颗治疗牙/位点的病历资料。再生治疗采用釉基质衍生物或牛源性异种移植物联合胶原膜，具体方案根据每例的临床特征选择。牙周结局依据探诊深度、临床附着水平、影像学骨缺损大小以及术后随访检查时的牙齿存活情况进行评估。术后临床与影像学参数均观察到显著改善。术后3–5、6–8、10–13和18–24个月的牙齿存活率分别为98.45%、97.67%、96.12%和93.02%。这些发现提示，GTR对于经选择的伴重度牙周缺损犬是一种保牙治疗选择。然而，由于随访不完整且时间不一、病例数随时间减少，且未纳入对照组，长期结局应谨慎解读。
关键词：骨缺损，临床附着水平，犬，引导组织再生，牙周疾病，探诊深度
牙周炎是指牙齿支持组织的炎症，包括牙龈、牙周膜和牙槽骨，其特征为组织破坏和牙周袋形成，导致探诊深度增加（Lim等，2022）。牙科疾病的管理通常包括牙周炎治疗、牙髓操作和引导组织再生（GTR）（Bellows等，2019）。犬牙周病极为常见，3岁犬的发病率高达85%（Lobprise和Dodd，2019），且即使给予专科护理也往往难以稳定（Gengler，2013）。进展性牙周炎可破坏牙龈和牙槽骨，并常导致牙齿脱落（McFadden和Marretta，2013；Wallis和Holcombe，2020）。在犬中，GTR被推荐用于管理中重度牙周炎（Bellows等，2019）。此外，拔牙后6个月牙槽骨体积可减少高达63%（Sato等，2022），这对犬的口腔健康不利。在人牙科中，可摘义齿和种植体支持式固定义齿已成为可靠的治疗选择。然而，种植体植入可能受到骨高度和/或宽度不足、炎症及种植体周围骨丢失的限制，常需进行骨增量手术（Bal等，2023）。在兽医牙科中，治疗决策往往复杂，且可能并不总能被主人充分理解。
犬在牙齿脱落或拔除后可以存活，但这些结局可能带来不良后果。保留牙齿，尤其是犬齿和裂齿，有利于整体健康，因为这些牙齿对于抓取、切割和咀嚼肉类及其他食物至关重要（Lee等，2023）。牙周退变通常不可逆，通过牙周组织重建实现功能恢复被认为是现代牙科的主要目标。已提出多种干预措施以促进牙周组织再生、阻止疾病进展或防止进一步恶化，包括激光治疗（Zuckerman等，2024）、干细胞治疗（Crossman等，2018）、基于生物材料的方法（Sun等，2023）以及引导组织再生技术（Esposito等，2005；Artzi等，2015）。
GTR利用组织屏障选择性靶向特定细胞群，并结合组织形态发生因子（如釉基质衍生物）刺激组织生长（Artzi等，2015）。该技术通过应用屏障阻止不良软组织长入，同时促进成骨细胞向缺损部位迁移，从而实现骨重建。在人牙科中，只要有可能，优先选择GTR等晚期牙周操作而非拔牙。然而，关于GTR用于骨再生的疗效、成功率和并发症率的临床数据极为有限。
本研究旨在评估GTR治疗部分牙周缺损的临床与影像学结局。随访持续1–2年，本研究特别旨在确定骨获得和功能恢复的潜在阈值。
材料与方法
动物资源护理与使用伦理委员会批准了本回顾性研究方案（批准号RAMC 20-RS-11）。本研究实施的所有操作均按照批准的指南和方案进行。已获得参与许可，且机构负责人授权发表研究结果。
动物选择、临床病史与诊断
本回顾性研究纳入了2020年3月至2023年7月期间，由主人带至韩国首尔中浪区皇家动物医疗中心兽医牙科部的犬类患者。我们向主人提供了关于手术操作的全面信息，并获得了他们的书面知情同意。我们获取了每只患者的详细临床病史，包括从领养到就诊时的一般健康状况、既往口腔护理措施（如洁牙和刷牙）以及口腔疾病的任何临床症状（包括口臭、疼痛和/或单侧出血）。在审查病史和牙科病史后，所有患者均接受了全面的临床检查和影像学评估以确认诊断（图1）。
[图：引导组织再生（GTR）治疗回顾性研究的动物纳入与排除标准流程图]
动物纳入标准与随访
在GTR重建手术恢复并出院后，建议主人于术后3、6、12、18和24个月返回进行随访检查。每次随访检查包括牙周探诊深度（PD）、临床附着水平（CAL）评估以及牙科X线摄影以测量骨缺损大小（BDS）。
然而，主人依从性存在差异，随访间隔并不统一。根据术后影像学检查的时间，动物被分配到四个随访组：3–5个月（n=42）、6–8个月（n=13）、10–13个月（n=6）和18–24个月（n=6）（图1，表1）。牙齿存活由兽医直接进行临床或影像学检查确定，或在无法进行多次术后复查时，根据主人提供的信息通过电话随访确定。
Table 1. Guided tissue regeneration corrects bone defects and improves probing depth and clinical attachment loss in dogs
| Groups | Time lines | Bone defect (mm) | Probing depth (mm) | CAL (mm) |
| 3–5 months ( n = 42) | preoperative | 2.76 ± 0.14 | 4.56 ± 0.10 | 3.25 ± 0.11 |
| postoperative | 0.77 ± 0.10*** | 1.87 ± 0.05*** | 2.08 ± 0.06*** | |
| 6–8 months ( n = 13) | preoperative | 3.14 ± 0.21 | 4.72 ± 0.15 | 3.15 ± 0.20 |
| postoperative | 0.50 ± 0.06*** | 2.06 ± 0.17*** | 1.86 ± 0.04*** | |
| 10–13 months ( n = 6) | preoperative | 2.93 ± 0.16 | 4.60 ± 0.12 | 3.13 ± 0.13 |
| postoperative | 0.29 ± 0.08*** | 2.10 ± 0.05*** | 1.89 ± 0.06*** | |
| 18–24 months ( n = 6) | preoperative | 3.39 ± 0.33 | 4.29 ± 0.12 | 2.83 ± 0.20 |
| postoperative | 0.08 ± 0.10*** | 2.05 ± 0.04*** | 1.44 ± 0.11*** |
若犬只接受过GTR且在术后3–12个月内至少进行过一次麻醉下的术后随访评估，则符合纳入本回顾性研究的条件。额外电话随访可至24个月。若术前数据或至少一次术后随访数据集（包括牙周探诊和牙科影像学结果）不可用，或未获得长达24个月的电话随访，则排除该病例。67只犬符合纳入标准并纳入研究。
每只犬收集的临床数据包括品种、性别、年龄、体重、治疗牙齿、治疗部位在牙齿上的确切位置、所用骨移植材料类型、所用屏障膜类型以及GTR部位。
手术操作
在术前血液检查和胸部X线摄影后，患者接受麻醉并给予静脉输液治疗。随后进行口腔消毒，并在洁治前后获取标准化临床照片。患者取胸卧或仰卧位进行牙科X线摄影。由兽医记录异常牙齿的数量和位置、牙周病的严重程度和分布、牙结石的存在、牙齿磨损（磨耗）、龋齿以及其他口腔异常，包括口鼻瘘、皮肤瘘、脓性分泌物和缺牙。
两名经验丰富的外科医生实施了所有手术治疗已识别的牙周病变。术前和术后PD及CAL由Chul Park和Kwangil Han独立记录，最终分析采用平均值。此外，所有作者均对BDS进行了复核。在重建手术前，所有患者均在术前2–3小时接受预防性抗生素和镇痛药，随后进行长期术后用药。仅在确认充分的全麻和局麻后才进行手术。
麻醉以丙泊酚（6–8 mg/kg i.v.）诱导，以七氟烷（1–5%）维持（Kim et al. 2020）。整个手术过程中提供正压通气。使用自动麻醉系统（PAIEON; J & TEC, Goyang-si, Gyeonggi-do, Republic of Korea）持续监测心电图和呼气末CO2（Jeong et al. 2019）。术后最初24小时内，每4–6小时给予注射用镇痛药，每8小时给予抗生素。术后口服药物包括曲马多（2–4 mg/kg每8–12小时）、头孢氨苄（22 mg/kg每12小时）以及主治兽医开具的非甾体抗炎药，持续7–14天（Seo et al. 2024; Han et al. 2025）。
手术入路由牙槽骨缺损的位置和患牙决定。一般而言，手术过程包括牙龈翻瓣、缺损部位软组织去除、根面平整和皮质骨穿孔。再生治疗包括牛源性异种移植材料（Bio-Oss®；Geistlich Pharma AG，Wolhusen，瑞士）或釉基质衍生物（Emdogain®；Biora AB，Malmö，瑞典）。其与可吸收胶原膜联合应用：Bio-Gide®（Geistlich）或细胞外基质基膜（Lyso-Gide；Oscotec Inc.，Seongnam，韩国）或胶原膜NatraFuse®（VETEREGEN，Hanam-si，韩国）。
将膜修剪适配缺损，首先使用骨接合螺钉将其固定于舌侧或腭侧。随后将移植材料置入缺损内，并使用钛钉将膜进一步稳定于颊侧。注意防止膜与邻牙接触。必要时，在二期技术中使用帐篷螺钉以维持足够的再生空间。然后复位瓣并使用不可吸收缝线关闭。膜置于骨与牙龈组织之间后，维持有利于愈合和再生的保护性空间。膜在愈合过程中逐渐吸收，术后根据手术部位的愈合情况拆除缝线。
统计分析
数据使用Prism v5.03（GraphPad Software Inc.，San Diego，CA，美国）进行分析。根据比较类型和数据分布，统计分析采用单因素方差分析（ANOVA），随后进行Bonferroni事后检验、Student t检验或Mann-Whitney U检验。结果以均值±均值标准误（SEM）或比例表示。P < 0.05视为有统计学意义。
结果
研究队列
共检索并筛选了205份病历。其中，138例因以下原因被排除：使用GTR以外的手术或治疗方法治疗牙科疾病（n = 110）以及引导骨再生后缺乏术后影像学随访数据（n = 28）。GTR手术使用Emdogain和胶原膜在61个区域进行（47.29%，61/129），使用Bio-Oss和胶原膜在64个区域进行（49.61%，64/129），使用NatraFuse在4个区域进行（3.10%，4/129）。在129个治疗区域中，65个（50.39%）为牙周垂直骨缺损，53个（41.09%）为根分叉骨缺损，11个（8.53%）为牙间骨缺损。
性别和品种
共在67只犬中治疗了129个牙周缺损。其中，28只犬（41.79%）为雌性（24只已绝育，4只未绝育）。39只（58.21%）为雄性（38只已去势，1只未去势）。犬的年龄范围为2至18岁，平均为8.51 ± 0.44岁。
研究样本包括19个品种。最常见的品种为贵宾犬（16/67，23.88%）、西施犬（10/67，14.93%）、混血犬（5/67，7.46%）、马尔济斯犬（4/67，5.97%）、金毛寻回犬（4/67，5.97%）和吉娃娃（4/67，5.97%）。其他品种包括雪纳瑞（3/67，4.48%）、博美犬（3/67，4.48%）、柴犬（3/67，4.48%）、比熊犬（3/67，4.48%）、约克夏梗（2/67，2.99%）、威尔士柯基犬（2/67，2.99%）和可卡犬（2/67，2.99%）。边境牧羊犬、马尔泰犬、迷你杜宾犬、斯皮茨犬、巴哥犬和丰山犬各有一例。
GTR手术的数量和部位
每只犬接受GTR治疗的牙齿数量为1至9颗，平均每只犬2.12个部位。25只犬（37.31%）在单一部位进行GTR，42只犬（62.69%）在多个部位进行。在多部位治疗的犬中，治疗区域数量为2至9个。具体而言，42只犬中有29只（69.05%）在2个部位接受治疗，9只（21.43%）在3个部位，3只（7.14%）在4个部位，1只（2.38%）在9个部位（图2）。
[图：每例引导组织再生手术治疗区域数量的患病率和分布（A）数量]
第四前臼齿（PM4；49/129，37.98%）是最常治疗的牙齿，其次是犬齿（44/129）、第一臼齿（M1；14/129，10.85%）和第一前臼齿（PM1；3/129）。此外，129例手术中有11例（8.53%）涉及牙间GTR，包括犬齿PM1（8/129，6.20%）、PM4–M1（2/129，1.55%）和PM4–PM3（1/129，0.78%）。GTR手术最常见的部位是右侧PM4，上颌24例，下颌4例。左侧相应数值分别为20例和1例。总体而言，129颗治疗牙齿中有86颗（66.67%）位于上颌，显著高于下颌数量（43/129，33.33%）（表2）。
Table 2. Number and percentage of dental GTR procedures performed in dogs stratified by anatomical location
| Maxilla | |||||||||||||||||||||
| right | left | ||||||||||||||||||||
| M2 | M1 | PM4 | PM3 | PM2 | PM1 | C | I3 | I2 | I1 | I1 | I2 | I3 | C | PM1 | PM2 | PM3 | PM4 | M1 | M2 | ||
| Total | – | 4 | 24 | – | – | 1 | 12 | 1 | 1 | 1 | – | – | – | 9 | 1 | – | – | 20 | 4 | 1 | |
| Percentage | – | 3.10 | 18.60 | – | – | 0.78 | 9.30 | 0.78 | 0.78 | 0.78 | – | – | – | 6.98 | 0.78 | – | – | 15.50 | 3.10 | 0.78 | |
| GTR performed in intra-dental bone defect | – | – | 1 | – | 2 | – | – | – | – | – | – | 2 | – | – | 2 | – | |||||
| Percentage | – | – | 0.78 | – | 1.55 | – | – | – | – | – | – | 1.55 | – | 1.55 | – | ||||||
| GTR performed in one site | 47 | – | – | – | – | – | – | – | – | – | 39 | ||||||||||
| GTR performed in maxilla | 86 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
GTR的临床结局
在本研究中，治疗成功基于牙齿存活和牙周指数改善进行评估，包括PD和BDS的降低以及CAL的增加。基线时，骨缺损大小范围为1.10至5.75 mm，129个治疗位点的平均值为2.76 ± 0.11 mm。PD范围为4.0至8.0 mm（平均4.55 ± 0.06 mm），而CAL范围为2.0至6.75 mm（平均3.16 ± 0.08 mm）。
在3至5个月随访时，可获得42例病例中93个位点的影像学和临床数据。平均骨缺损大小从2.76 ± 0.14显著降至0.77 ± 0.10 mm（P < 0.001）。平均PD从4.56 ± 0.08 mm显著降至1.87 ± 0.05 mm（P < 0.001），平均CAL从3.25 ± 0.11 mm降至2.08 ± 0.06 mm（P < 0.001）（图3和图4）。
[图：临床诊断、手术过程及术后影像学随访（长达]
[图：随访结果显示，骨缺损、探诊深度和临床附着丧失在18–]
在6–8个月随访时，可获得13名患者中15个位点的影像学和临床数据。平均骨缺损大小从3.14 ± 0.21 mm显著降至0.50 ± 0.06 mm（P < 0.001）。平均PD从4.72 ± 0.15 mm降至2.06 ± 0.17 mm（P < 0.001），平均CAL从3.15 ± 0.20 mm降至1.86 ± 0.04 mm（P < 0.001）（图4和图5）。
[图：临床诊断、手术过程及长期术后影像学随访的代表性图像]
在10至13个月随访时，可获得6例病例中7个位点的影像学和临床数据。平均骨缺损大小从2.93 ± 0.16显著降至0.29 ± 0.08 mm（P < 0.001）。平均PD从4.60 ± 0.16降至2.10 ± 0.04 mm（P < 0.001），平均CAL从3.13 ± 0.13降至1.89 ± 0.06 mm（P < 0.001）（图4和图6）。
[图：临床诊断、手术过程及长期术后影像学随访的代表性图像]
在最终18至24个月随访检查时，可获得6名患者中10个位点的影像学和临床数据。平均骨缺损大小从3.39 ± 0.33显著降至0.08 ± 0.05 mm（P < 0.001）。平均PD也从4.29 ± 0.12降至2.05 ± 0.04 mm（P < 0.001），平均CAL从2.83 ± 0.19降至1.44 ± 0.11 mm（P < 0.001）（图4和图7）。
[图：临床诊断、手术过程及长期术后影像学随访的代表性图像 Gui]
在24个月随访期内，累积牙齿存活率从3–5个月时的98.45%（n = 127/129）降至18–24个月时的93.02%（n = 120/129），中间存活率分别为6–8个月时的97.67%（n = 126/129）和10–13个月时的96.12%（n = 124/129）。
讨论
牙周炎是一种牙龈的慢性感染性疾病，可导致牙齿支持结构破坏，并最终导致牙齿脱落。可能需要手术干预以阻止疾病进展并恢复受损组织。已开发出多种手术技术用于牙周组织再生，包括引导组织再生（GTR）、骨移植和釉基质衍生物（EMDs）的应用（Esposito等，2005）。本回顾性研究表明，使用天然骨替代材料Geistlich Bio-Oss®或釉基质衍生物Emdogain®联合可吸收胶原膜的GTR技术，可有效减小骨缺损大小和探诊深度，同时显著改善CAL获得。3–5、6–8、10–13和18–24个月的存活率分别为98.45%（127/129）、97.67%（126/129）、96.12%（124/129）和93.02%（120/129）。基于临床和影像学发现及存活率，GTR治疗犬严重牙周病取得了临床成功的结果。与我们研究结果一致，既往实验研究表明，应用Bio-Oss和可吸收胶原膜可有效促进骨再生，表现为三维重建成像和组织形态计量学分析所测得的骨体积/总体积、骨小梁数量、骨小梁分离度和骨小梁厚度的改善（Alkan等，2013；Li等，2018）。组织病理学研究也证实，在应用EMD或Bio-Oss Collagen的位点，3个月时可见明显的骨再生（Alkan等，2013）。此外，本研究表明，我们的GTR操作不仅刺激了骨再生，还促进了牙周膜愈合，表现为显著的CAL获得。这是一项涉及客户所有犬的回顾性临床研究，无法进行micro-CT和组织病理学分析。然而，组织学评估对于确认GTR的真实再生结果仍是必要的。
引导骨再生（GBR）和引导组织再生（GTR）是牙科手术技术，通过在龈上皮与牙槽骨或牙周膜组织之间放置屏障膜，促进在骨量或组织量不足以实现最佳功能、美观或修复重建的区域形成新骨和牙周组织。简而言之，GTR涉及病变牙周组织四种组织中三种的再生——牙骨质、牙周膜和牙槽骨，而第四种组织（牙龈组织）通过膜屏障被排除在外（Alqahtani等，2023）。GBR与GTR相似，但通常指牙槽嵴增量或骨再生手术，而GTR特指再生硬组织，包括骨和牙骨质，以及参与牙周附着的软组织。这恢复了牙周附着（Miloro，2004）。因此，GTR旨在再生所有三个主要牙周组成部分。
使用屏障膜进行直接骨再生的方法最早在1959年的骨科研究中被描述（Hurley等，1959）。引导组织再生的基本理论概念后来由Melcher于1976年建立，他强调了从愈合部位排除不良细胞类型以促进所需组织形成的重要性（Melcher，1976）。在20世纪80年代牙周再生研究取得良好临床结果后，研究注意力转向使用引导骨再生重建牙槽骨缺损。引导组织再生在牙科中引起了广泛关注。Nyman于1982年首次引入屏障膜方法（Nyman等，1982），Gottlow后来于1986年创造了“引导组织再生”这一术语（Gottlow等，1986；Srivastava等，2015）。GTR被定义为一组旨在通过差异性组织反应再生丢失的牙周结构的手术。屏障膜用于防止上皮和牙龈结缔组织接触根面，其前提是这种接触会干扰牙周再生。因此，GTR膜的目的是排除上皮和牙龈结缔组织，保持缺损与牙齿之间的空间，并稳定血凝块。GBR在概念上与GTR相似，但主要侧重于硬组织再生以及牙周附着的软组织。GBR的原理最早由Dahlin等人于1988年使用大鼠模型进行研究（Dahlin等，1988）。如果通过膜排除邻近软组织，则可以增强成骨细胞选择性长入骨缺损，这后来由Kostopoulos和Karring于1994年证实（Kostopoulos和Karring，1994）。不可吸收膜需要二次手术移除，并且人们对提供等效或更优治疗效果的生物可吸收膜越来越感兴趣。此外，可吸收膜减少患者不适，降低治疗成本，并消除与二次手术相关的并发症风险（Bottino和Thomas，2015）。
Emdogain是一种釉基质衍生物（EMD），主要用于增强牙骨质形成；然而，它也可以刺激间充质细胞中成骨相关基因的表达，并可能作为成骨促进剂用于治疗破坏性牙周病变（Lee等，2020）。辅助使用EMD预期对牙周组织和骨愈合产生协同和有益效果。在本研究中，我们进行了一项犬类临床试验，发现Emdogain联合胶原膜应用显著减小了骨缺损尺寸和PD。与这些发现一致，先前在人类中进行的对照临床试验表明，辅助使用EMD可改善早期伤口愈合，并在非手术和手术牙周治疗中促进牙骨质介导的新附着和牙周再生（Wennstrom和Lindhe，2002；Tonetti等，2004）。
Bio-Oss是一种来源于牛骨的多孔骨矿物质。它通过脱蛋白处理牛骨制成，其结构与人类松质骨相似。它主要用于矫正骨缺损，但也广泛用于牙科以促进牙周骨生长和组织再生（Alkan等，2013；Li等，2018）。在本犬类临床试验中，我们发现Bio-Oss联合胶原膜显著减小了骨缺损尺寸和PD。
在本研究中，接受引导组织再生术（GTR）治疗重度牙周病、骨缺损和明显牙周袋的犬中，58.21%（39/67）为雄性，41.79%（28/67）为雌性。这些发现与先前报道一致，该报道指出牙周病在雄性犬中发生率为52.7%，雌性犬为47.3%（Wallis et al. 2021）。雄性犬比雌性犬更具攻击性和大胆性（Scandurra et al. 2018），这可能使它们易发生牙齿损伤和牙周炎。此外，我们发现接受GTR的犬中92.54%（62/67）已绝育。同样，一项先前调查报道70.8%的犬已绝育（Wallis et al. 2021）。这一观察结果得到了一项早期研究的进一步支持（Marshall et al. 2014）。本研究中绝育犬比例较高可能反映了韩国首尔的绝育率高于其他国家（Jeong et al. 2019; Seo et al. 2020）。此外，在骨骼生长和成熟完成前进行绝育可能促进骨和关节疾病的发生（Oberbauer et al. 2019; Seo et al. 2020）。因此，需要进一步研究来评估绝育对牙骨质、牙周膜和牙槽骨的潜在影响，这些均可能影响口腔和牙齿健康。
在本研究纳入的19个犬品种中，最常见的为贵宾犬（23.88%）、西施犬（14.93%）、混种犬（7.46%）、马尔济斯犬（5.97%）、金毛寻回犬（5.97%）、吉娃娃（5.97%）、雪纳瑞（4.48%）、博美犬（4.48%）、柴犬（4.48%）和比熊犬（4.48%）。这些发现与先前研究一致，该研究表明玩具贵宾犬的牙龈和牙槽骨显著薄于其他中小型品种（Wallis and Holcombe 2020）。牙龈厚度减少也与牙周病高发病率相关（Harvey 2005）。这些研究之间的差异可能归因于地理或区域差异。一项先前研究报道牙周病在约克夏梗中最为流行（25.2%），其次是可卡犬（12.8%）和杰克罗素梗（9.5%）（O’Neill et al. 2014）。然而，韩国大多数犬为小型品种（Jeong et al. 2019; Seo et al. 2020）。遗传差异和品种特异性口腔形态已被提出作为牙周病的危险因素（Wallis and Holcombe 2020）。小型犬的牙齿相对于大型品种往往较大，且更易发生错颌畸形和牙齿疾病（Wallis and Holcombe 2020; Wallis et al. 2021）。
据我们所知，这是首次描述犬位点特异性GTR的报道。在所有接受GTR治疗的牙齿中，上颌第四前臼齿（PM4）占49/129（37.98%），其次是犬齿占44/129（34.11%），下颌第一臼齿（M1）占14/129（10.85%），上颌第一前臼齿（PM1）占3/129（2.33%）。这些牙齿的难度可能与使用常规刷牙技术充分去除牙菌斑的挑战有关。先前研究报道前臼齿和臼齿，特别是PM4和PM1，牙周病患病率较高（Kortegaard et al. 2008; Wallis and Holcombe 2020）。一些研究者认为前臼齿的牙周病变患病率最高（Hoffmann and Gaengler 1996; Wallis et al. 2019），而另一些研究者提出切齿特别易患牙齿病变（Marshall et al. 2014; Wallis et al. 2018）。在本研究中，GTR在上颌的实施频率（66.67%，86/129）显著高于下颌（33.33%，43/129），尽管从上颌和下颌拔除的牙齿数量无显著差异。与这一发现一致，多项研究报道上颌牙齿牙周病患病率高于下颌牙齿（Kortegaard et al. 2008; Wallis et al. 2019; Wallis and Holcombe 2020）。
不能排除选择偏倚，因为这项回顾性研究仅纳入了返回进行预定再评估的患者。通过电话进行长期随访且未进行临床或影像学再检查的犬可能有不同的结局；因此，尽管所有者确认了电话随访，所报告的成功率可能高估了GTR的真实长期有效性。术后治疗包括由临床医生酌情决定的镇痛药和抗生素，并建议所有者在3、6、12、18和24个月时返回再评估。然而，医疗记录中未一致提供关于所有者家庭口腔卫生依从性、菌斑控制和术后轻微并发症的详细信息。系统健康状况、年龄相关变化以及其他可能影响牙周愈合和再生结局的患者相关因素也未受控制。这些局限性可能导致治疗反应的变异性，在解释本研究发现时应予以考虑。同样，选择一种生物材料而非另一种的理由无法从医疗记录中完全确定。这些因素可能影响了结局的变异性，应在未来研究中加以解决。本研究还强调了回顾性兽医牙科研究固有的实际挑战。
在本回顾性病例系列的局限性范围内，GTR可能代表一种有前景的保牙治疗选择，适用于部分患有严重牙周缺损的犬。该治疗与良好的临床和影像学结果以及术后随访检查中较高的牙齿存活率相关。然而，缺乏对照组、长期随访不完整且存在差异、后期评估时间点病例数量有限以及缺乏组织学确认，限制了该推断的强度。需要进一步的前瞻性对照研究来确认GTR在犬中的长期疗效、稳定性和临床可预测性。前臼齿、犬齿和臼齿是最常治疗的牙齿，且常涉及多颗牙齿和多个位点。这些发现可能有助于临床医生进行病例选择和治疗计划制定。
资金声明
本研究由韩国首尔中浪区皇家动物医疗中心兽医牙科系研究基金以及韩国国家研究基金会（NRF）资助项目（RS-2026-25558831）支持。
利益冲突
作者声明无利益冲突。
参考文献
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Abstract
Clinical evidence on guided tissue regeneration (GTR) in dogs with advanced periodontal defects is limited. This retrospective study aimed to evaluate the clinical and radiographic outcomes and tooth survival after GTR in dogs with severe periodontal disease. The medical records of 67 dogs with 129 treated teeth/sites in total were reviewed. The regenerative treatment consisted of an enamel matrix derivative or bovine-derived xenograft in combination with a collagen membrane, which was selected based on the clinical characteristics of each case. Periodontal outcomes were assessed based on probing depth, clinical attachment level, radiographic bone defect size, and tooth survival at postoperative follow-up examinations. Significant postoperative improvements were observed in the clinical and radiographic parameters. The tooth survival rates at 3–5, 6–8, 10–13, and 18–24 months were 98.45%, 97.67%, 96.12%, and 93.02%, respectively. These findings suggest that GTR is a tooth-preserving treatment option for selected dogs with severe periodontal defects. However, the long-term outcomes should be interpreted cautiously because the follow-up was incomplete and variable, the number of cases decreased over time, and no control group was included.
Keywords: bone defect, clinical attachment level, dogs, guided tissue regeneration, periodontal disorder, probing depth
Periodontitis refers to inflammation of the supporting tissues of the teeth, including the gingiva, periodontal ligament, and alveolar bone, and is characterised by tissue destruction and formation of periodontal pockets that result in increased probing depth (Lim et al. 2022). Management of dental disorders generally includes treatment of periodontitis, endodontic procedures, and guided tissue regeneration (GTR) (Bellows et al. 2019). Canine periodontal disease is highly prevalent, with an incidence of up to 85% for dogs aged 3 years (Lobprise and Dodd 2019) and is often difficult to stabilise even with specialised care (Gengler 2013). Progressive periodontitis can destroy the gingiva and alveolar bone and frequently results in tooth loss (McFadden and Marretta 2013; Wallis and Holcombe 2020). In dogs, GTR is recommended for managing moderate-to-severe periodontitis (Bellows et al. 2019). Furthermore, the alveolar bone volume may decrease by up to 63% at 6 months following tooth extraction (Sato et al. 2022), which is detrimental to canine oral health. In human dentistry, removable dentures and implant-supported fixed prostheses have emerged as reliable therapeutic options. However, implant placement may be restricted by inadequate bone height and/or width, inflammation, and peri-implant bone loss, often necessitating bone augmentation procedures (Bal et al. 2023). In veterinary dentistry, treatment decisions are often complex and may not always be fully appreciated by owners.
Dogs can survive after tooth loss or extraction, but these outcomes may have adverse consequences. Preserving teeth, particularly canine and carnassial teeth, benefits overall health because they are important for grasping, cutting, and chewing meat and other food materials (Lee et al. 2023). Periodontal degeneration is usually irreversible, and functional recovery through periodontal tissue reconstruction is considered a major goal of modern dentistry. Several interventions have been proposed to promote periodontal tissue regeneration, halt disease progression, or prevent further deterioration. These include laser therapy (Zuckerman et al. 2024), stem cell therapy (Crossman et al. 2018), biomaterial-based approaches (Sun et al. 2023), and guided tissue regeneration techniques (Esposito et al. 2005; Artzi et al. 2015).
GTR uses tissue barriers to selectively target specific cell populations, along with tissue morphogenic factors such as enamel matrix derivatives to stimulate tissue growth (Artzi et al. 2015). This technique reconstructs bone by applying barriers that prevent the ingrowth of undesirable soft tissue while promoting the migration of bone-forming cells into the defect site. In human dentistry, advanced periodontal procedures such as GTR are preferred over tooth extraction whenever possible. However, clinical data on the efficacy, success, and complication rates of GTR for bone regeneration are extremely limited.
This study aimed to assess the clinical and radiographic outcomes of GTR for the treatment of partial periodontal defects. The follow-up lasted for 1–2 years, and this study specifically aimed to determine potential thresholds for bone gain and functional recovery.
MATERIAL AND METHODS
The Ethics Committee for the Care and Use of Animal Resources approved this retrospective study protocol (Approval No. RAMC 20-RS-11). All procedures performed in this study were conducted in accordance with approved guidelines and protocols. Permission for participation was obtained, and the director of the institution authorised the publication of the findings.
Animal selection, clinical history and diagnosis
This retrospective study included canine patients presented by their owners to the Department of Veterinary Dentistry at the Royal Animal Medical Centre, Jungnang-gu, Seoul, Republic of Korea between March 2020 and July 2023. We provided the owners with comprehensive information about the surgical procedure, and they provided written informed consent. We obtained a detailed clinical history for each patient. This included general health status from adoption to presentation; previous oral care practices such as tartar removal and tooth brushing; and any clinical signs of oral disease, including halitosis, pain, and/or unilateral bleeding. All patients underwent a comprehensive clinical examination and radiographic evaluation to confirm the diagnosis after reviewing their medical and dental histories (Figure 1).
[图：Flowchart of animal inclusion and exclusion criteria for a retrospective study on guided tissue regeneration (GTR) thera]
Animal inclusion criteria and follow-up
After recovery from GTR reconstruction surgery and discharge from the hospital, owners were advised to return for follow-up examinations at 3, 6, 12, 18, and 24 months postoperatively. Each follow-up examination included assessments of periodontal probing depth (PD), clinical attachment level (CAL), and dental radiography to measure bone defect size (BDS).
However, owner compliance varied, and the follow-up intervals were not uniform. Based on the timing of the postoperative radiographic examinations, the animals were allocated to four follow-up groups: 3–5 months (n = 42), 6–8 months (n = 13), 10–13 months (n = 6), and 18–24 months (n = 6) (Figure 1, Table 1). Tooth survival was determined by direct clinical or radiographic examination performed by a veterinarian, or by telephone follow-up based on information provided by the owners when multiple postoperative re-examinations were not available.
Table 1. Guided tissue regeneration corrects bone defects and improves probing depth and clinical attachment loss in dogs
| Groups | Time lines | Bone defect (mm) | Probing depth (mm) | CAL (mm) |
| 3–5 months ( n = 42) | preoperative | 2.76 ± 0.14 | 4.56 ± 0.10 | 3.25 ± 0.11 |
| postoperative | 0.77 ± 0.10*** | 1.87 ± 0.05*** | 2.08 ± 0.06*** | |
| 6–8 months ( n = 13) | preoperative | 3.14 ± 0.21 | 4.72 ± 0.15 | 3.15 ± 0.20 |
| postoperative | 0.50 ± 0.06*** | 2.06 ± 0.17*** | 1.86 ± 0.04*** | |
| 10–13 months ( n = 6) | preoperative | 2.93 ± 0.16 | 4.60 ± 0.12 | 3.13 ± 0.13 |
| postoperative | 0.29 ± 0.08*** | 2.10 ± 0.05*** | 1.89 ± 0.06*** | |
| 18–24 months ( n = 6) | preoperative | 3.39 ± 0.33 | 4.29 ± 0.12 | 2.83 ± 0.20 |
| postoperative | 0.08 ± 0.10*** | 2.05 ± 0.04*** | 1.44 ± 0.11*** |
Dogs were eligible for inclusion in this retrospective study if they had undergone GTR and had at least one postoperative follow-up assessment performed under anaesthesia within 3–12 months after the procedure. Additional telephone follow-up was available for up to 24 months. Cases were excluded if preoperative data or at least one postoperative follow-up dataset, including periodontal probing and dental radiographic findings, were unavailable or telephone follow-up for up to 24 months had not been obtained. Sixty-seven dogs fulfilled the inclusion criteria and were enrolled in the study.
Clinical data collected for each dog included breed, sex, age, body weight, treated tooth, exact location of the treated site on the tooth, type of bone graft material used, type of barrier membrane applied, and site of GTR.
Surgical procedure
Following preoperative blood testing and thoracic radiography, the patients were anaesthetised and administered intravenous fluid therapy. Oral disinfection was subsequently performed, and standardised clinical photographs were obtained before and after scaling. Dental radiographs were acquired with the patient positioned in sternal or dorsal recumbency. A veterinarian recorded the number and location of abnormal teeth, severity and distribution of periodontal disease, presence of dental calculus, tooth wear (attrition), dental caries, and other oral abnormalities including oronasal fistulas, cutaneous fistulas, purulent discharge, and missing teeth.
Two experienced surgeons performed all surgical procedures to treat the identified periodontal lesions. Pre- and postoperative PD and CAL were recorded independently by Chul Park and Kwangil Han, and the mean values were used for the final analysis. In addition, the BDS was rechecked by all the authors. Before reconstructive surgery, all patients received prophylactic antibiotics and analgesics 2–3 h preoperatively, followed by long-term postoperative medication. Surgery was performed only after adequate general and local anaesthesia were confirmed.
Anaesthesia was induced with propofol (6–8 mg/kg i.v.) and maintained with sevoflurane (1–5%) (Kim et al. 2020). Positive pressure ventilation was provided throughout the procedure. Electrocardiography and end-tidal CO2 were continuously monitored using an automated anaesthetic system (PAIEON; J & TEC, Goyang-si, Gyeonggi-do, Republic of Korea) (Jeong et al. 2019). During the first 24 h after surgery, injectable analgesics were administered every 4–6 h and antibiotics were administered every 8 hours. The postoperative oral medications included tramadol (2–4 mg/kg every 8–12 h), cephalexin (22 mg/kg every 12 h), and non-steroidal anti-inflammatory drugs prescribed by the attending veterinarian for 7–14 days (Seo et al. 2024; Han et al. 2025).
The surgical approach was determined by the location of the alveolar bone defect and the affected tooth. In general, the procedure consisted of gingival flap elevation, soft tissue removal from the defect site, root surface planing, and cortical perforation. Regenerative treatment included bovine-derived xenograft material (Bio-Oss®; Geistlich Pharma AG, Wolhusen, Switzerland) or enamel matrix derivative (Emdogain®; Biora AB, Malmö, Sweden). This was applied in combination with a resorbable collagen membrane: Bio-Gide® (Geistlich) or an extracellular matrix-based membrane (Lyso-Gide; Oscotec Inc., Seongnam, Republic of Korea) or a collagen membrane NatraFuse® (VETEREGEN, Hanam-si, Republic of Korea).
The membrane was adapted to the defect and initially secured to the lingual or palatal side using osteosynthesis screws. The graft material was subsequently placed into the defect and the membrane was further stabilised on the buccal side using titanium pins. Care was taken to prevent contact between the membrane and adjacent teeth. When necessary, tenting screws were used in the two-stage technique to maintain sufficient space for regeneration. The flaps were then repositioned and closed using non-resorbable sutures. After placement between the bone and gingival tissue, the membrane maintains a protected space conducive to healing and regeneration. The membrane was gradually resorbed during healing, and the sutures were removed postoperatively according to the healing status of the surgical site.
Statistical analysis
Data were analysed using Prism v5.03 (GraphPad Software Inc., San Diego, CA, USA). Depending on the type of comparison and data distribution, statistical analysis was performed using one-way analysis of variance (ANOVA), followed by Bonferroni’s post hoc test, Student’s t-test, or the Mann-Whitney U test. The results are presented as the mean ± standard error of the mean (SEM) or as proportions. A value of P < 0.05 was considered statistically significant.
RESULTS
Study cohort
In total, 205 patient records were retrieved and screened. Of these, 138 cases were excluded for the following reasons: treatment of dental disorders using surgical or therapeutic procedures other than GTR (n = 110) and absence of postoperative radiographic follow-up data after guided bone regeneration (n = 28). GTR surgery was performed using Emdogain and a collagen membrane in 61 regions (47.29%, 61/129), Bio-Oss and a collagen membrane in 64 regions (49.61%, 64/129), and NatraFuse in 4 regions (3.10%, 4/129). Among the 129 treated regions, 65 (50.39%) had periodontal vertical bone defects, 53 (41.09%) had furcation bone defects, and 11 (8.53%) had interdental bone defects.
Sex and breeds
A total of 129 periodontal defects were treated in 67 dogs. Of these, 28 dogs (41.79%) were female (24 spayed and 4 intact). Thirty-nine (58.21%) were male (38 castrated and 1 intact). The dogs ranged in age from 2 to 18 years, with a mean of 8.51 ± 0.44 years.
The study sample included 19 breeds. The most common breeds were Poodle (16/67, 23.88%), Shih Tzu (10/67, 14.93%), mixed (5/67, 7.46%), Maltese (4/67, 5.97%), Golden Retriever (4/67, 5.97%), and Chihuahua (4/67, 5.97%). Other breeds included the Schnauzer (3/67, 4.48%), Pomeranian (3/67, 4.48%), Shiba Inu (3/67, 4.48%), Bichon Frise (3/67, 4.48%), Yorkshire Terrier (2/67, 2.99%), Welsh Corgi (2/67, 2.99%), and Cocker Spaniel (2/67, 2.99%). Each of the Border Collie, Maltipoo, Miniature Pinscher, Spitz, Pug, and Pungsan breeds was represented by one case.
Number and sites of GTR surgery
The number of teeth treated with GTR per dog ranged from 1 to 9, with a mean of 2.12 sites per dog. GTR was performed at a single site in 25 dogs (37.31%) and at multiple sites in 42 dogs (62.69%). Among the dogs undergoing multisite treatment, the number of treated regions ranged from 2 to 9. Specifically, 29 of 42 dogs (69.05%) received treatment at 2 sites, 9 of 42 dogs (21.43%) at 3 sites, 3 of 42 dogs (7.14%) at 4 sites, and 1 of 42 dogs (2.38%) at 9 sites (Figure 2).
[图：Prevalence and distribution of the number of regions treated with guided tissue regeneration surgery per case (A) Number]
The fourth premolar (PM4; 49/129, 37.98%) was the most frequently treated tooth, followed by the canine (44/129), first molar (M1; 14/129, 10.85%), and first premolar (PM1; 3/129). In addition, 11 of the 129 procedures (8.53%) involved interdental GTR, including canine PM1 (8/129, 6.20%), PM4–M1 (2/129, 1.55%), and PM4–PM3 (1/129, 0.78%). The most common site of GTR surgery was the right PM4, with 24 cases in the maxilla and 4 in the mandible. On the left side, the corresponding values were 20 and 1, respectively. Overall, 86 of the 129 treated teeth (66.67%) were located in the maxilla, which was significantly higher than the number in the mandible (43/129, 33.33%) (Table 2).
Table 2. Number and percentage of dental GTR procedures performed in dogs stratified by anatomical location
| Maxilla | |||||||||||||||||||||
| right | left | ||||||||||||||||||||
| M2 | M1 | PM4 | PM3 | PM2 | PM1 | C | I3 | I2 | I1 | I1 | I2 | I3 | C | PM1 | PM2 | PM3 | PM4 | M1 | M2 | ||
| Total | – | 4 | 24 | – | – | 1 | 12 | 1 | 1 | 1 | – | – | – | 9 | 1 | – | – | 20 | 4 | 1 | |
| Percentage | – | 3.10 | 18.60 | – | – | 0.78 | 9.30 | 0.78 | 0.78 | 0.78 | – | – | – | 6.98 | 0.78 | – | – | 15.50 | 3.10 | 0.78 | |
| GTR performed in intra-dental bone defect | – | – | 1 | – | 2 | – | – | – | – | – | – | 2 | – | – | 2 | – | |||||
| Percentage | – | – | 0.78 | – | 1.55 | – | – | – | – | – | – | 1.55 | – | 1.55 | – | ||||||
| GTR performed in one site | 47 | – | – | – | – | – | – | – | – | – | 39 | ||||||||||
| GTR performed in maxilla | 86 | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
Clinical consequences of GTR
In this study, treatment success was evaluated based on tooth survival and improvement in periodontal indices, including reductions in PD and BDS and an increase in CAL. At baseline, the bone defect size ranged from 1.10 to 5.75 mm, with a mean value of 2.76 ± 0.11 mm across the 129 treated sites. The PD ranged from 4.0 to 8.0 mm (mean 4.55 ± 0.06 mm), while the CAL ranged from 2.0 to 6.75 mm (mean 3.16 ± 0.08 mm).
At the 3-to-5-month follow-up, radiographic and clinical data were available for 93 sites from 42 cases. The mean bone defect size decreased significantly from 2.76 ± 0.14 to 0.77 ± 0.10 mm (P < 0.001). The mean PD was significantly reduced from 4.56 ± 0.08 mm to 1.87 ± 0.05 mm (P < 0.001), and the mean CAL decreased from 3.25 ± 0.11 mm to 2.08 ± 0.06 mm (P < 0.001) (Figures 3 and 4).
[图：Representative images for the clinical diagnosis, surgical procedure, and radiographic postoperative follow-up for up to]
[图：Follow-up results demonstrated gradual improvement in bone defects, probing depth, and clinical attachment loss over 18–]
At the 6–8-month follow-up, radiographic and clinical data were available for 15 sites in 13 patients. The mean bone defect size decreased significantly from 3.14 ± 0.21 mm to 0.50 ± 0.06 mm (P < 0.001). The mean PD was reduced from 4.72 ± 0.15 mm to 2.06 ± 0.17 mm (P < 0.001), and the mean CAL decreased from 3.15 ± 0.20 mm to 1.86 ± 0.04 mm (P < 0.001) (Figures 4 and 5).
[图：Representative images for the clinical diagnosis, surgical procedure, and long-term radiographic postoperative follow-up]
At the 10-to-13-month follow-up, radiographic and clinical data were available for 7 sites from 6 cases. The mean bone defect size decreased significantly from 2.93 ± 0.16 to 0.29 ± 0.08 mm (P < 0.001). The mean PD was reduced from 4.60 ± 0.16 to 2.10 ± 0.04 mm (P < 0.001), and the mean CAL decreased from 3.13 ± 0.13 to 1.89 ± 0.06 mm (P < 0.001) (Figures 4 and 6).
[图：Representative images for clinical diagnosis, surgical procedure, and long-term radiographic postoperative follow-up up ]
At the final 18-to-24-month follow-up examination, radiographic and clinical data were available for 10 sites from 6 patients. The mean bone defect size decreased significantly from 3.39 ± 0.33 to 0.08 ± 0.05 mm (P < 0.001). The mean PD was also reduced from 4.29 ± 0.12 to 2.05 ± 0.04 mm (P < 0.001), and the mean CAL decreased from 2.83 ± 0.19 to 1.44 ± 0.11 mm (P < 0.001) (Figures 4 and 7).
[图：Representative images for clinical diagnosis, surgical procedure, and long-term radiographic postoperative follow-up Gui]
The cumulative tooth survival rate decreased from 98.45% (n = 127/129) at 3–5 months to 93.02% (n = 120/129) at 18–24 months over the 24-month follow-up period, with intermediate survival rates of 97.67% (n = 126/129) at 6–8 months and 96.12% (n = 124/129) at 10–13 months.
DISCUSSION
Periodontitis is a chronic infectious disease of the gingiva that leads to the destruction of supporting structures of teeth and, ultimately, tooth loss. Surgical intervention may be required to halt disease progression and restore damaged tissues. Various surgical techniques, including guided tissue regeneration (GTR), bone grafting, and application of enamel matrix derivatives (EMDs), have been developed to regenerate periodontal tissues (Esposito et al. 2005). This retrospective study showed that GTR techniques using the natural bone substitute Geistlich Bio-Oss® or enamel matrix derivative Emdogain®, combined with an absorbable collagen membrane, effectively reduced bone defect size and probing depth while significantly improving CAL gain. The survival rates at 3–5, 6–8, 10–13, and 18–24 months were 98.45% (127/129), 97.67% (126/129), 96.12% (124/129), and 93.02% (120/129), respectively. Based on the clinical and radiographic findings and survival rate, GTR treatment for severe periodontal disease in dogs resulted in clinically successful outcomes. Consistent with our findings, previous experimental studies have shown that the application of Bio-Oss and absorbable collagen membranes effectively promotes bone regeneration, as evidenced by improvements in bone volume/total volume, trabecular number, trabecular separation, and trabecular thickness measured using three-dimensional reconstruction imaging and histomorphometric analysis (Alkan et al. 2013; Li et al. 2018). Histopathological studies have also demonstrated marked bone regeneration at EMD- or Bio-Oss Collagen-treated sites at 3 months after application (Alkan et al. 2013). In addition, the present study showed that our GTR procedures not only stimulated bone regeneration but also promoted periodontal ligament healing, as indicated by significant CAL gain. This was a retrospective clinical study involving client-owned dogs, and micro-CT and histopathological analyses could not be performed. Nevertheless, histological evaluation is necessary to confirm the true regenerative outcomes of GTR.
Guided bone regeneration (GBR) and GTR are dental surgical techniques that use barrier membranes placed between the gingival epithelium and alveolar bone or periodontal ligament tissues to facilitate the formation of new bone and periodontal tissues in areas with insufficient bone or tissue volume for optimal function, aesthetics, or prosthetic restoration. In simple terms, GTR involves the regeneration of three of the four tissues of the diseased periodontium – the cementum, periodontal ligament, and alveolar bone, while the fourth tissue (gingival tissue) is excluded by means of a membrane barrier (Alqahtani et al. 2023). GBR is similar to GTR, but it generally refers to ridge augmentation or bone regenerative procedures, whereas GTR specifically focuses on regenerating hard tissues, including bone and cementum, and the soft tissues involved in periodontal attachment. This restores periodontal attachment (Miloro 2004). Thus, GTR aims to regenerate all three major periodontal components.
The use of barrier membranes for direct bone regeneration was first described in orthopaedic research in 1959 (Hurley et al. 1959). The fundamental theoretical concepts of guided tissue regeneration were later established by Melcher in 1976, who emphasised the importance of excluding undesirable cell types from healing sites to enable the formation of desired tissues (Melcher 1976). Following favourable clinical results in periodontal regeneration studies during the 1980s, research attention shifted toward the reconstruction of alveolar bone defects using guided bone regeneration. Guided tissue regeneration has attracted substantial attention in dentistry. Nyman first introduced the barrier membrane approach in 1982 (Nyman et al. 1982), and Gottlow later coined the term “guided tissue regeneration” in 1986 (Gottlow et al. 1986; Srivastava et al. 2015). GTR has been defined as a group of procedures aimed at regenerating lost periodontal structures through differential tissue responses. Barrier membranes are used to prevent the epithelium and gingival connective tissue from contacting the root surface based on the premise that such contact interferes with periodontal regeneration. Accordingly, the purpose of GTR membranes is to exclude the epithelial and gingival connective tissue, preserve the space between the defect and tooth, and stabilise blood clots. GBR is conceptually similar to GTR but primarily focuses on hard tissue regeneration in addition to the soft tissues of periodontal attachment. The principle of GBR was first examined by Dahlin et al. in 1988 using a rat model (Dahlin et al. 1988). Selective ingrowth of osteogenic cells into a bone defect can be enhanced if the adjacent soft tissue is excluded by a membrane, as later confirmed by Kostopoulos and Karring in 1994 (Kostopoulos and Karring 1994). Non-resorbable membranes require a second surgical procedure for removal, and there has been an increasing interest in bioabsorbable membranes that provide equivalent or superior therapeutic outcomes. In addition, resorbable membranes reduce patient discomfort, lower treatment costs, and eliminate the risk of complications associated with secondary surgery (Bottino and Thomas 2015).
Emdogain is an EMD primarily used to enhance cementogenesis; however, it can also stimulate the expression of osteogenesis-related genes in mesenchymal cells and may serve as an osteopromotive agent in the treatment of destructive periodontal lesions (Lee et al. 2020). The adjunctive use of EMD is expected to exert synergistic and beneficial effects on periodontal tissue and bone healing. In the present study, we conducted a canine clinical trial and found that the application of Emdogain with a collagen membrane significantly reduced the bone defect size and PD. Consistent with these findings, previous controlled clinical trials in humans have shown that the adjunctive use of EMD improves early wound healing and promotes cementum-mediated new attachment and periodontal regeneration in both nonsurgical and surgical periodontal therapies (Wennstrom and Lindhe 2002; Tonetti et al. 2004).
Bio-Oss is a porous bone mineral derived from bovine bones. It is produced by deproteinising bovine bone, resulting in a structure similar to that of human cancellous bone. It is primarily used to correct bone defects but is also widely used in dentistry to promote periodontal bone growth and tissue regeneration (Alkan et al. 2013; Li et al. 2018). In the present canine clinical trial, we found that Bio-Oss in combination with a collagen membrane significantly reduced bone defect size and PD.
Among the dogs undergoing GTR for severe periodontal disease, bone defects, and marked PD in the present study, 58.21% (39/67) were male and 41.79% (28/67) were female. These findings are consistent with a previous report indicating that periodontal disease occurred in 52.7% of male dogs and 47.3% of female dogs (Wallis et al. 2021). Male dogs have greater aggressiveness and boldness than females (Scandurra et al. 2018), which may predispose them to dental injuries and periodontitis. Additionally, we found that 92.54% (62/67) of dogs that underwent GTR were neutered. Similarly, a previous survey reported that 70.8% of the dogs were neutered (Wallis et al. 2021). This observation is further supported by an earlier study (Marshall et al. 2014). The high proportion of neutered dogs in the present study may reflect the greater prevalence of neutering in Seoul, Korea, than in other countries (Jeong et al. 2019; Seo et al. 2020). Furthermore, neutering before the completion of skeletal growth and maturation may contribute to the development of bone and joint disorders (Oberbauer et al. 2019; Seo et al. 2020). Therefore, additional research is needed to evaluate the potential effects of neutering on the cementum, periodontal ligament, and alveolar bone, all of which may influence oral and dental health.
Among the 19 dog breeds included in this study, the most frequently represented were Poodle (23.88%), Shih Tzu (14.93%), mixed breed (7.46%), Maltese (5.97%), Golden Retriever (5.97%), Chihuahua (5.97%), Schnauzer (4.48%), Pomeranian (4.48%), Shiba Inu (4.48%), and Bichon (4.48%). These findings agree with those of a previous study showing that toy poodles have significantly thinner gingiva and alveolar bone than other small- and medium-sized breeds (Wallis and Holcombe 2020). Reduced gingival thickness is also associated with a high incidence of periodontal diseases (Harvey 2005). The differences among these studies may be attributed to geographic or regional variations. A previous study reported that periodontal disease was most prevalent in Yorkshire Terriers (25.2%), followed by Cocker Spaniels (12.8%) and Jack Russell Terriers (9.5%) (O’Neill et al. 2014). However, most dogs in Korea are small breeds (Jeong et al. 2019; Seo et al. 2020). Genetic differences and breed-specific oral morphologies have been proposed as risk factors for periodontal diseases (Wallis and Holcombe 2020). Small dogs tend to have relatively larger teeth than larger breeds and are more susceptible to malocclusion and dental diseases (Wallis and Holcombe 2020; Wallis et al. 2021).
To the best of our knowledge, this is the first report to describe site-specific GTR in dogs. Among all teeth treated with GTR, PM4 accounted for 49/129 (37.98%), followed by canine teeth for 44/129 (34.11%), M1 for 14/129 (10.85%), and PM1 for 3/129 (2.33%). The difficulty associated with these teeth may arise from the challenge of adequately removing plaque using routine brushing techniques. Previous studies have reported a higher prevalence of periodontal disease in the premolars and molars, particularly PM4 and PM1 (Kortegaard et al. 2008; Wallis and Holcombe 2020). Some investigators have suggested that premolars have the highest prevalence of periodontal lesions (Hoffmann and Gaengler 1996; Wallis et al. 2019), whereas others have proposed that incisors are particularly vulnerable to dental pathologies (Marshall et al. 2014; Wallis et al. 2018). In the present study, GTR was performed significantly more frequently in the maxilla (66.67%, 86/129) than in the mandible (33.33%, 43/129), although there was no significant difference in the number of teeth extracted from the maxilla and mandible. Consistent with this finding, several studies have reported a higher prevalence of periodontal disease involving maxillary than involving mandibular teeth (Kortegaard et al. 2008; Wallis et al. 2019; Wallis and Holcombe 2020).
Selection bias cannot be excluded because this retrospective study included only patients who returned for scheduled re-evaluation. Dogs assessed during the long-term follow-up by telephone and without clinical or radiographic re-examination may have had different outcomes; therefore, the reported success rates may have overestimated the true long-term effectiveness of GTR despite owner-confirmed telephone follow-up. Postoperative treatment included analgesics and antibiotics at the clinician’s discretion, and owners were advised to return for re-evaluation at 3, 6, 12, 18, and 24 months. However, detailed information on owner compliance with home-based oral hygiene, plaque control, and minor postoperative complications was not consistently available in the medical records. Systemic health status, age-related changes, and other patient-related factors that may influence periodontal healing and regenerative outcomes were also not controlled. These limitations may have contributed to the variability in the treatment response and should be considered when interpreting the present findings. Likewise, the rationale for selecting one biomaterial over another could not be fully determined from the medical records. These factors may have influenced the outcome variability and should be addressed in future investigations. This study also highlighted the practical challenges inherent to retrospective veterinary dental research.
Within the limitations of this retrospective case series, GTR may represent a promising tooth-preserving treatment option for selected dogs with severe periodontal defects. Treatment was associated with favourable clinical and radiographic outcomes and high tooth survival at postoperative follow-up examinations. However, the absence of a control group, incomplete and variable long-term follow-up, limited number of cases at later evaluation points, and lack of histological confirmation limit the strength of this inference. Further prospective, controlled studies are warranted to confirm the long-term efficacy, stability, and clinical predictability of GTR in dogs. Premolars, canines, and molars were the most commonly treated teeth, and multiple teeth and sites were frequently involved. These findings may assist clinicians with case selection and treatment planning.
Funding Statement
Supported by the research fund of Department of Veterinary Dentistry, Royal Animal Medical Centre, Jungnang-gu, Seoul, Republic of Korea and Grants from the National Research Foundation (NRF) of Korea (RS-2026-25558831).
Conflict of interest
The authors declare no conflict of interest.
REFERENCES
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