The recent Global Burden of Disease Study indicates that severe periodontitis is the 6th most prevalent disease worldwide, with an overall prevalence of 11.2% and around 743 million people affected, and the global burden of periodontal disease increased by 57.3% from 1990 to 2010. As periodontitis is the major cause of tooth loss in the adult population worldwide, these individuals are at risk of multiple tooth loss, edentulism, and masticatory dysfunction, thereby affecting their nutrition, quality of life, and self-esteem, as well as imposing huge socioeconomic impacts and healthcare costs. The global burden of periodontal diseases remains high, and trends in risk factors, improved tooth retention, and an aging population are likely to bear further increases. Associated morbidity, costs, and socio-economic impact will continue to rise.

In addition to the need to treat more severe forms of periodontitis by implanting bone substitutes inside periodontal pockets, there are extremely frequent requests to preserve the alveolus after tooth extraction.

Alveolar ridge preservation is a popular technique, currently accounting for about 29% of all procedures involving bone substitutes. Application of this technique is necessary if the subsequent installation of dental implants based on titanium alloys is planned. The prevalence of this technique in dental medicine is also indicated by the fact that the global cost of bone replacement materials for the preservation of the alveolar ridge is estimated at 190 million dollars per year, with an expected annual growth of approximately 11.4%.

The implantation of the ALBO-OS for the treatment of periodontal pockets with probing depth more than 5mm and alveolar ridge augmentation is considered an essential method for significant improvement of oral health for patients with advanced periodontitis. Following the main requirements for an ideal bone substitute for filling the periodontal pockets and alveolar sockets, such as its high porosity, satisfactory chemistry and surface topography characteristics, as well as desirable microstructure and mechanical properties, ALBO-OS shows numerous advantages compared with recently developed used bone grafts, particularly expressed in their excellent osteoconductive and osteoinductive properties, have been approved on a wide scale of animal assays.

Therefore, it will be applied in clinical trials for the healing of severe periodontitis disease when implantation of the bone substitute is required. Financial support of the study is provided by the sponsor's consortium, with ALBOS Ltd as the main sponsor. The recruitment site is the Home Health, Foča, Republic of Srpska, Bosnia and Herzegovina.

Inclusion Criteria in case of regenerative periodontal treatment:

• Informed consent has been signed
• Age 18 years and above
• Stable dose of current regular medication (specify type if needed) for at least 4 weeks before trial entry
• Acceptable laboratory analysis
• No systemic diseases which could influence the outcome of the therapy, or interfere in any way with treatment outcomes, such as they are: an acute or chronic infection (e.g., osteomyelitis) at the site of implantation, uncontrolled metabolic diseases such as diabetes, osteomalacia, disorders of the thyroid gland, or heavy disturbances in the liver or kidney
• Good compliance with individual plaque control following initial periodontal therapy
• Teeth to be involved should be vital (intact or with fillings but without the presence of caries lesion) with score 0 mobility
• The selected 2- or 3-wall intrabony defect depth, which ranges from 3-5 mm, as detected in diagnostic Panoramic Radiograph and clinical examination
• Selected pocket depth (PD) ≥ 5 mm and clinical attachment level (CAL) ≥ 3 mm at the site of the endosseous defect
• Angle radiographic bone defect ≤55 and ≥15
• The availability of program monitoring and maintenance of oral hygiene
• No history of periodontal therapy in the previous 6 months
• No history of antibiotics' intake or other medications affecting the periodontium in the previous 3 months
• Minimum number of teeth is 16 (50% of all teeth/mouth) to achieve a desirable treatment effect
• To preserve the dimensions of the bone of the alveolar ridge, in the indication of alveolus preservation, immediately after previous tooth extraction, in the case of planned installation of implants based on titanium alloys, it is necessary to preserve the alveolus for at least two months before implant installation

Exclusion Criteria in case of regenerative periodontal treatment:

• Pregnancy and lactation 6 months before the study and during the study
• Significant renal or hepatic impairment
• Scheduled elective surgery or other procedures requiring general anesthesia or local (oral) surgery during the trial
• Subject with a life expectancy of less than 6 months
• Periodontal treatment for the previous year
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial
• Participation in another research trial involving an investigational product of a similar type in the past 12 weeks

Eligibility criteria if ARP was indicated:

Inclusion criteria: age ≥18 years; good general health; non-smokers or light smokers (up to 10 cigarettes per day); no active periodontal disease; presence of single or multiple hopeless teeth; tooth/teeth to be extracted having at least one neighboring tooth and at least two socket walls with 3 mm of alveolar bone height; more than two residual teeth after extraction to be used as references during image superimposition.

Exclusion criteria: pregnancy or lactation; presence of systemic conditions and medications that alter bone metabolism (i.e. uncontrolled diabetes mellitus, renal or hepatic impairment, immunodeficiency, severe autoimmune diseases, malignancy, radiotherapy or chemotherapy in the past 5 years, intake of corticosteroids, bisphosphonates or other anti-resorptive drugs); active periodontal disease; heavy smoking (more than 10 cigarettes per day).