Periodontal regeneration in horizontal osseous defect

Abstract

Horizontal bone loss represents the most frequently encountered pattern of bone destruction in periodontitis and remains a significant therapeutic challenge due to limited regenerative possibilities. It is characterized by a reduction in bone height with the absence of contained bony walls, thereby restricting the predictability of regenerative outcomes. Despite its high prevalence, effective management of horizontal bone defects remains an area requiring further exploration. Intramarrow penetration (IMP) promotes bone healing by exposing cancellous bone, inducing bleeding, and facilitating the migration of progenitor cells and vascular elements into the grafted region. Low-level laser therapy (LLLT) enhances mesenchymal stem cell proliferation and stimulates the release of growth factors, thereby supporting bone regeneration without causing thermal damage to surrounding tissues. Sticky bone, a grafting material enriched with autologous fibrin, acts as a biological scaffold that supports cellular migration, enhances angiogenesis, and accelerates tissue repair. This case series investigates the clinical benefits of combining IMP, LLLT, and sticky bone in the management of horizontal bone loss in periodontitis patients. The objective of the study was to evaluate the regenerative potential of this multimodal approach in improving bone regeneration outcomes.

INTRODUCTION

Periodontitis is a chronic inflammatory condition that affects the supporting structures of the teeth. Clinically, it is characterized by loss of gingival attachment, deepening of the gingival sulcus resulting in periodontal pocket formation, destruction of the periodontal ligament, and progressive alveolar bone loss.[1]

Apart from the reduction in bone height, periodontal disease also alters the structural morphology of alveolar bone, leading to different patterns of bone loss. Among these, horizontal bone loss is the most commonly observed pattern and is often described as a zero-wall defect. In this condition, bone height is reduced while the bone margins remain relatively perpendicular to the tooth surface.[2]

Regenerative periodontal procedures generally demonstrate more predictable outcomes in contained intrabony defects due to favorable defect morphology and enhanced space maintenance. In contrast, horizontal bone defects present limited regenerative predictability because of the absence of supporting bony walls and compromised vascular containment.[3]

The primary objective of periodontal therapy is to restore lost structure, function, esthetics, and patient comfort.[4] Although horizontal bone loss is highly prevalent, it has historically received limited attention in regenerative research due to its unfavorable morphology and unpredictable treatment outcomes.[5] Therefore, the development of innovative therapeutic strategies aimed at improving regenerative predictability in horizontal defects remains an important focus in periodontal therapy.

Low-level laser therapy (LLLT), also referred to as therapeutic or cold laser therapy, is a nonablative modality that does not cut or vaporize tissues. It has been shown to stimulate mesenchymal stem cell proliferation and enhance growth factor expression, both of which are essential for periodontal regeneration.[6]

Intramarrow penetration (IMP) is commonly recommended as an adjunct to osseous reconstructive procedures. This technique enhances healing by exposing cancellous bone, promoting bleeding, and enabling the migration of progenitor cells and vascular components into the grafted area.[7]

Sticky bone is a grafting material prepared using injectable platelet-rich fibrin (I-PRF) and functions as both a hemostatic barrier and a scaffold for migrating fibroblasts. It enhances cellular activity, promotes angiogenesis, and supports tissue regeneration.[8]

The principles of tissue engineering, including scaffolds, stem cells, and growth factors, can be effectively applied in the management of horizontal osseous defects through the combined use of IMP, LLLT, and sticky bone. In this integrated approach, IMP facilitates the recruitment of progenitor cells, LLLT enhances cellular activity, and sticky bone provides structural stability enriched with growth factors, collectively supporting periodontal regeneration.[9,10]

CASE SERIES

A total of five patients diagnosed with horizontal bone loss and presenting with probing pocket depths ranging from 5 to 7 mm were selected from the outpatient department of periodontology. Each patient underwent a comprehensive clinical and radiographic assessment followed by completion of Phase I periodontal therapy. Surgical management for all patients included open flap debridement (OFD), IMP, LLLT, and placement of sticky bone. Clinical and radiographic parameters were evaluated at predetermined intervals as outlined in Table 1.

Table 1.

Parameters assessed and their timelines

Parameters	Baseline (before Phase I)	Baseline (after Phase I)	At 6-month follow-up	At 9-month follow-up
Full mouth PI	✓		✓	✓
Full mGI	✓		✓	✓
PD		✓	✓	✓
CAL		✓	✓	✓
RDD		✓	✓	✓
DF%			✓	✓

RDD – Radiographic defect depth; DF – Defect fill; CAL – Clinical attachment level; PD – Probing depth; mGI – Mouth modified gingival index; PI – Plaque Index

Although cone-beam computed tomography (CBCT) enables three-dimensional volumetric evaluation, standardized intraoral periapical radiographs obtained using the paralleling technique with grid calibration were employed in this study to reduce radiation exposure and maintain consistency across follow-up visits. All radiographs were standardized using the paralleling technique to ensure reproducibility.

Radiographic defect depth (RDD) and defect fill percentage (DF%) were calculated using standardized measurements.

RDD = (RP to B) – (RP to A)

where RP = reference point, A = Alveolar crest, and B = base of the horizontal bone defect.

The RDD was determined by subtracting the distance from the reference point to the alveolar crest from the distance between the reference point and the base of the defect. The percentage of DF was calculated by comparing baseline defect depth with the defect depth measured at 9 months, expressed as a percentage of the baseline value.

Before surgery, patients were instructed to rinse with 0.12% chlorhexidine digluconate solution. Extraoral antisepsis was achieved using gauze soaked in povidone–iodine solution. Local anesthesia was administered using 2% lignocaine with 1:80,000 epinephrine.

Intracrevicular and interdental incisions were placed to elevate a full-thickness flap using the Kirkland flap technique. Following flap reflection, the exposed root surfaces and surrounding bone were meticulously debrided, and granulation tissue was removed [Figure 1].

Figure 1.

Flap reflection and defect debridement using the Kirkland technique

IMP was performed at the defect site using a 0.25-mm round bur attached to a slow-speed handpiece under continuous normal saline irrigation to prevent thermal injury [Figure 2].

Figure 2.

Intramarrow penetration performed at the defect site

Subsequently, the defect region was subjected to low-level laser biostimulation using an 810-nm diode laser at a power setting of 0.5 W with a 0.6-mm initiated optical fiber tip. The laser was delivered in a continuous, noncontact mode for 20 s, followed by an 8-s pause. This cycle was repeated three times, resulting in a total effective irradiation time of approximately 60 s [Figure 3].

Figure 3.

Low-level laser application to the exposed bone surface

Sticky bone was then prepared according to the protocol described by Sohn et al. I-PRF was collected under sterile conditions and mixed with xenograft particles. The mixture was allowed to polymerize for approximately 5–10 min until a cohesive sticky bone mass was obtained [Figure 4].

Figure 4.

Sticky bone placement at the defect

The prepared sticky bone was carefully placed into the defect area, and the surgical site was sutured using 3–0 silk sutures to achieve primary closure.

During follow-up evaluations at 6 months and 9 months, reductions in plaque index (PI) and modified gingival index scores were observed compared to baseline values. Improvements in both clinical and radiographic parameters were noted [Table 2]. The mean DF% recorded at 6 months and 9 months was 27% ±0.06 and 32.5% ±0.04, respectively [Figure 5].

Table 2.

Mean±standard deviation of all parameters at 3 timelines

Parameters	Baseline (mean±SD)	6 months (mean±SD)	9 months (mean±SD)
PD	6.4±0.48	3±0	3.2±0.44
CAL	6.8±1.09	4±0.89	4.2±1.09
RDD	6.8±1.09	5±1.00	4.6±0.89
DF%	-	27±0.06	32.50±0.04

RDD – Radiographic defect depth; DF – Defect fill; CAL – Clinical attachment level; PD – Probing depth, SD: Standard deviation

Figure 5.

Radiographic changes showing defect fill (red circles) at (a) Baseline, (b) 6 months, and (c) 9 months

Ethical considerations

The present case series was conducted in accordance with the CARE guidelines for case series reporting. Written informed consent was obtained from all participants before initiation of treatment. The study protocol adhered to the ethical principles outlined in the Declaration of Helsinki.

Statistical considerations

Given the limited sample size (n = 5), descriptive statistical analysis was performed. Mean values and standard deviations were calculated for all evaluated clinical and radiographic parameters [Tables 1 and 2].

DISCUSSION

The present case series assessed the effectiveness of a combination regenerative approach involving IMP, LLLT, and sticky bone in the management of horizontal bone loss defects.

Sticky bone is a biologically active composite material formed by combining autologous platelet concentrates, such as PRF or concentrated growth factors (CGFs), with particulate bone graft materials. Its adaptability allows it to be used in various types of osseous defects. The fibrin matrix within sticky bone entraps platelets and leukocytes, enabling the gradual release of growth factors that accelerate both hard and soft tissue regeneration. Furthermore, sticky bone reduces soft tissue invasion into the grafted region and eliminates the need for additional chemical modifiers, thereby enhancing regenerative potential. Sareen et al., in their systematic review, reported favorable clinical and radiographic outcomes associated with sticky bone in the management of alveolar defects and periodontal surgical procedures.[11,12]

Bone decortication has become a valuable adjunct in regenerative periodontal procedures aimed at improving bone formation. It has been shown to enhance defect resolution and promote greater bone fill. IMP, also referred to as decortication, involves the creation of small perforations in cortical bone to access the cancellous bone beneath. This procedure facilitates the migration of osteogenic cells, improves vascular supply, and enhances the intrinsic regenerative capacity of the surrounding bone. Sharma et al. investigated the role of IMP combined with advanced PRF in intrabony defects and reported significant reductions in probing depth, PI, and gingival index, along with improvements in clinical attachment levels and increased bone fill in the experimental group compared to controls.[13]

LLLT has gained increasing recognition as an adjunctive tool in periodontal regeneration due to its stimulatory effects on cellular activity. It enhances cell proliferation, improves local circulation, and promotes tissue healing. In addition, LLLT has been shown to decrease inflammatory mediators and facilitate bone remodeling through stimulation of mesenchymal stem cells and osteoblastic activity. Rathod et al. demonstrated that LLLT promotes the release of fibroblast growth factors, leading to increased matrix formation and cellular proliferation, thereby contributing to improved bone regeneration.[14]

Recent developments in periodontal regenerative therapy emphasize the integration of biologically active materials with surgical techniques to optimize healing outcomes. The observations made in this case series are consistent with previous investigations that support the synergistic effects of combined regenerative modalities.

Debnath et al. evaluated the use of PRF along with IMP in the treatment of horizontal defects across 94 sites. Their findings indicated that the group treated with OFD, IMP, and PRF demonstrated the highest DF% (45.09%) along with significant improvements in probing depth and clinical attachment levels compared to groups treated with OFD alone or with IMP only.[3]

Similarly, Thalaimalai et al. reported that the adjunctive use of LLLT with PRF resulted in significant improvements in clinical and radiographic parameters in intrabony defects. Greater reductions in probing depth and RDD were observed in the test group, suggesting a synergistic interaction between LLLT and biologically active materials.[7]

Ghoderao et al. compared the regenerative potential of sticky bone with CGFs in the treatment of intrabony defects. Although both treatment modalities demonstrated improvements in clinical outcomes, the sticky bone group exhibited superior gains in clinical attachment levels at 12 months, further supporting its regenerative capability.[9]

In the present case series, progressive improvements in clinical and radiographic parameters were observed throughout the 9-month follow-up period [Table 2 and Figures 5 and 6]. The observed reduction in probing depth, gain in clinical attachment levels, and gradual radiographic DF may be attributed to the combined biological actions of the selected treatment modalities.

Figure 6.

Probing depth changes from (a) Baseline to (b) 6 months and (c) 9 months

The regenerative response observed in this study may be explained by the complementary mechanisms of action of the three treatment components. IMP enhances vascular infiltration and promotes the migration of progenitor cells into the defect area. LLLT stimulates cellular proliferation and modulates growth factor activity. Sticky bone provides structural stability and acts as a scaffold enriched with biologically active factors, supporting sustained cellular activity and tissue regeneration.

From a clinical perspective, the improvements observed in noncontained horizontal defects suggest that biologically driven regenerative stimulation may partially compensate for unfavorable defect morphology. This finding is clinically relevant, as horizontal defects are traditionally associated with limited regenerative success due to the absence of natural bony walls required for maintaining graft stability.

However, several limitations of the present study must be acknowledged. The lack of a control group restricts direct comparison with conventional therapeutic approaches. In addition, the small sample size limits the generalizability of the findings. The use of two-dimensional radiographic methods may also reduce measurement accuracy when compared to advanced three-dimensional imaging modalities such as CBCT.

Future investigations should incorporate larger sample populations, randomized controlled study designs, and advanced imaging techniques such as CBCT-based volumetric analysis. Histological evaluation of regenerated tissues would further strengthen the evidence supporting the effectiveness of this combined regenerative strategy.

CONCLUSION

Within the limitations of the present case series, the combined use of IMP, LLLT, and sticky bone demonstrated encouraging clinical and radiographic improvements in the management of horizontal osseous defects. This biologically synergistic treatment approach appears to enhance regenerative potential in noncontained periodontal defects. However, further controlled clinical studies with larger sample sizes and the use of advanced imaging modalities are necessary to confirm long-term predictability and treatment effectiveness.

Limitations

The present case series is subject to several limitations, including a small sample size, absence of a control group, relatively short follow-up duration, and reliance on two-dimensional radiographic assessment methods. In addition, histological confirmation of true periodontal regeneration was not performed, which limits the ability to conclusively verify the nature of the regenerated tissues.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.