**2. Aim**

The aim of the paper was to assess the e ffectiveness of the activity of piperacillin and tazobactam combination in the form of an intrapocket-administered chemotherapy. Its influence on the course of treatment, microbiome of the pocket, healing rate, adverse e ffects or lack of thereof, is in comparison with the gold standard of periodontitis treatment—the SRP procedure.

### **3. Materials and Methods**

Ten patients aged 24 to 56 (the average age was 39.5, 5 males, 5 females) with general periodontitis (loss of CAL on interproximal surfaces, CAL in >30% of teeth, with moderately symmetric bone loss in pantomographic image) were qualified for the study. The patients were healthy nonsmokers who had not used antibiotics within the period of 6 months prior to the study, were not allergic to penicillin, and had at least 10 teeth in the jaw. The excluded criteria were also diabetes mellitus and hypertension. The second stage of periodontitis was diagnosed in 1 case, the third stage in 6 cases, and the fourth in 3 cases. Degree distribution was 7 from B and 3 from C. All these individuals provided written consent for the proposed treatment protocol. The study was granted approval KB-600/2019 by the Bioethical Committee of Wrocław Medical University.

The procedure would begin with providing instructions on oral hygiene (the obtained average API value was below 20%). Subsequently, machine SRP (ultrasonic scaling with subgingival tips) under nerve block anesthesia in the mandible was performed during two visits. Examination of clinical parameters was conducted by one standardized periodontist (TK). The examinations determined parameters such as bleeding on probing (BoP), clinical attachment location (CAL), and periodontal depth (PD) in six measurement points around each tooth, except for the third molars. Then, microbiological material was collected from two symmetric pockets with similar PD, located on both sides of the dental arch; sterile filter paper was placed in the pockets for 30 s, and the samples were then transferred to transport test-tubes. During the same visit, the periodontist (ASJ) conducted analogous SRP under anesthesia in the jaw. At the end of the visit, a third periodontist (JZ) introduced Gelcide into the periodontal pockets, in accordance with the instructions of the manufacturer, applying randomization to odd-numbered patients in the order of their applications on the left, and even-numbered patients on the right. The randomization was known to only one person (JZ). The patients were informed about the possibility of attending an additional follow-up visit, if any adverse e ffects associated with the conducted treatment were noticed. If no such e ffects occurred, the follow-up visits took place one, four, and eight weeks after the initial examination. Clinical examination was conducted again at the last follow-up visit, and the material for microbiological tests (TK) was collected from the same pockets.

During microbiological testing, the PET deluxe test was applied. The test uses the PCR method in real time that makes it possible to quantify the total bacterial count (TBC) in the pocket as well as the red-complex bacteria (*Porphyromonas gingivalis*—P.g., *Treponema denticola*—T.d., and oraz *Tannerella forsythia*—T.f.), *Aggregatibacter actinomycetemcomitans*—A.a.), orange-complex bacteria (*Fusobacterium nucleatum*—F.n., *Prevotella intermedia*—P.i., and *Micromonas micros*—P.m., *Eubacterium nodatum-E.n.*), and green-complex bacteria (*Capnocytophaga gingivalis*—C.g.).

Due to lack of normality of distribution of the analyzed variables, nonparametric tests were used in statistical analysis: the Mann–Whitney U test for nonrelated variables and the Wilcoxon T-test for related variables and for groups below 25 participants. *p* ≤ 0.05 was adopted as the significance level. The Statistica package, version 13.1, was used.
