diff --git a/extension.json b/extension.json
index e72129cc..9d19c5bd 100644
--- a/extension.json
+++ b/extension.json
@@ -15,6 +15,7 @@
 		"CategoryTree": {
 			"class": "MediaWiki\\Extension\\CategoryTree\\CategoryTreePage",
 			"services": [
+				"DBLoadBalancerFactory",
 				"SearchEngineFactory"
 			]
 		}
@@ -97,6 +98,7 @@
 			"services": [
 				"CategoryTree.CategoryCache",
 				"MainConfig",
+				"DBLoadBalancerFactory",
 				"LinkRenderer"
 			]
 		},
diff --git a/includes/ApiCategoryTree.php b/includes/ApiCategoryTree.php
index 8e202545..177f7041 100644
--- a/includes/ApiCategoryTree.php
+++ b/includes/ApiCategoryTree.php
@@ -88,7 +88,7 @@ class ApiCategoryTree extends ApiBase {
 
 		$depth = isset( $options['depth'] ) ? (int)$options['depth'] : 1;
 
-		$ct = new CategoryTree( $options, $this->getConfig(), $this->linkRenderer );
+		$ct = new CategoryTree( $options, $this->getConfig(), $this->dbProvider, $this->linkRenderer );
 		$depth = $ct->optionManager->capDepth( $depth );
 		$ctConfig = $this->configFactory->makeConfig( 'categorytree' );
 		$html = $this->getHTML( $ct, $title, $depth, $ctConfig );
diff --git a/includes/CategoryTree.php b/includes/CategoryTree.php
index dea3f2dd..dfae29a5 100644
--- a/includes/CategoryTree.php
+++ b/includes/CategoryTree.php
@@ -36,6 +36,7 @@ use MediaWiki\SpecialPage\SpecialPage;
 use MediaWiki\Title\Title;
 use Parser;
 use RequestContext;
+use Wikimedia\Rdbms\IConnectionProvider;
 
 /**
  * Core functions for the CategoryTree extension, an AJAX based gadget
@@ -48,21 +49,27 @@ class CategoryTree {
 	/** @var Config */
 	private $config;
 
+	/** @var IConnectionProvider */
+	private $dbProvider;
+
 	/** @var LinkRenderer */
 	private $linkRenderer;
 
 	/**
 	 * @param array $options
 	 * @param Config $config
+	 * @param IConnectionProvider $dbProvider
 	 * @param LinkRenderer $linkRenderer
 	 */
 	public function __construct(
 		array $options,
 		Config $config,
+		IConnectionProvider $dbProvider,
 		LinkRenderer $linkRenderer
 	) {
 		$this->optionManager = new OptionManager( $options, $config );
 		$this->config = $config;
+		$this->dbProvider = $dbProvider;
 		$this->linkRenderer = $linkRenderer;
 	}
 
@@ -150,7 +157,7 @@ class CategoryTree {
 			return '';
 		}
 
-		$dbr = MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->getReplicaDatabase();
+		$dbr = $this->dbProvider->getReplicaDatabase();
 
 		$inverse = $this->optionManager->isInverse();
 		$mode = $this->optionManager->getOption( 'mode' );
@@ -272,7 +279,7 @@ class CategoryTree {
 	 * @return string
 	 */
 	public function renderParents( Title $title ) {
-		$dbr = MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->getReplicaDatabase();
+		$dbr = $this->dbProvider->getReplicaDatabase();
 
 		$res = $dbr->select(
 			'categorylinks',
diff --git a/includes/CategoryTreePage.php b/includes/CategoryTreePage.php
index f7c9f803..ce4e903d 100644
--- a/includes/CategoryTreePage.php
+++ b/includes/CategoryTreePage.php
@@ -29,6 +29,7 @@ use MediaWiki\Html\Html;
 use MediaWiki\SpecialPage\SpecialPage;
 use MediaWiki\Title\Title;
 use SearchEngineFactory;
+use Wikimedia\Rdbms\IConnectionProvider;
 
 /**
  * Special page for the CategoryTree extension, an AJAX based gadget
@@ -38,6 +39,9 @@ class CategoryTreePage extends SpecialPage {
 	/** @var string */
 	public $target = '';
 
+	/** @var IConnectionProvider */
+	private $dbProvider;
+
 	/** @var SearchEngineFactory */
 	private $searchEngineFactory;
 
@@ -45,12 +49,15 @@ class CategoryTreePage extends SpecialPage {
 	public $tree = null;
 
 	/**
+	 * @param IConnectionProvider $dbProvider
 	 * @param SearchEngineFactory $searchEngineFactory
 	 */
 	public function __construct(
+		IConnectionProvider $dbProvider,
 		SearchEngineFactory $searchEngineFactory
 	) {
 		parent::__construct( 'CategoryTree' );
+		$this->dbProvider = $dbProvider;
 		$this->searchEngineFactory = $searchEngineFactory;
 	}
 
@@ -100,7 +107,7 @@ class CategoryTreePage extends SpecialPage {
 			$options[$option] = $request->getVal( $option, $default );
 		}
 
-		$this->tree = new CategoryTree( $options, $config, $this->getLinkRenderer() );
+		$this->tree = new CategoryTree( $options, $config, $this->dbProvider, $this->getLinkRenderer() );
 
 		$this->getOutput()->addWikiMsg( 'categorytree-header' );
 
diff --git a/includes/Hooks.php b/includes/Hooks.php
index 3f4ef52a..e4f38df7 100644
--- a/includes/Hooks.php
+++ b/includes/Hooks.php
@@ -44,6 +44,7 @@ use Parser;
 use PPFrame;
 use RequestContext;
 use Skin;
+use Wikimedia\Rdbms\IConnectionProvider;
 use Wikimedia\Rdbms\IResultWrapper;
 
 /**
@@ -68,21 +69,27 @@ class Hooks implements
 	/** @var Config */
 	private $config;
 
+	/** @var IConnectionProvider */
+	private IConnectionProvider $dbProvider;
+
 	/** @var LinkRenderer */
 	private $linkRenderer;
 
 	/**
 	 * @param CategoryCache $categoryCache
 	 * @param Config $config
+	 * @param IConnectionProvider $dbProvider
 	 * @param LinkRenderer $linkRenderer
 	 */
 	public function __construct(
 		CategoryCache $categoryCache,
 		Config $config,
+		IConnectionProvider $dbProvider,
 		LinkRenderer $linkRenderer
 	) {
 		$this->categoryCache = $categoryCache;
 		$this->config = $config;
+		$this->dbProvider = $dbProvider;
 		$this->linkRenderer = $linkRenderer;
 	}
 
@@ -203,7 +210,7 @@ class Hooks implements
 			$parserOutput->addModules( [ 'ext.categoryTree' ] );
 		}
 
-		$ct = new CategoryTree( $argv, $this->config, $this->linkRenderer );
+		$ct = new CategoryTree( $argv, $this->config, $this->dbProvider, $this->linkRenderer );
 
 		$attr = Sanitizer::validateTagAttributes( $argv, 'div' );
 
@@ -326,7 +333,7 @@ class Hooks implements
 		if ( $mode !== null ) {
 			$options['mode'] = $mode;
 		}
-		$tree = new CategoryTree( $options, $this->config, $this->linkRenderer );
+		$tree = new CategoryTree( $options, $this->config, $this->dbProvider, $this->linkRenderer );
 
 		$cat = $this->categoryCache->getCategory( $title );